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Measurement, spatial spillover and influencing factors of agricultural carbon emissions efficiency in China
WU Haoyue, HUANG Hanjiao, HE Yu, CHEN Wenkuan
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Effects of tillage and straw returning method on the distribution of carbon and nitrogen in soil aggregates
ZHANG Yuming, HU Chunsheng, CHEN Suying, WANG Yuying, LI Xiaoxin, DONG Wenxu, LIU Xiuping, PEI Lin, ZHANG Hui
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Relationship between policy incentives, ecological cognition, and organic fertilizer application by farmers: Based on a moderated mediation model
SANG Xiance, LUO Xiaofeng, HUANG Yanzhong, TANG Lin
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Spatio-temporal evolution of carbon stocks in the Yellow River Basin based on InVEST and CA-Markov models
YANG Jie, XIE Baopeng, ZHANG Degang
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Effects of straw returning and fertilization on soil bacterial and fungal community structures and diversities in rice-wheat rotation soil
ZHANG Hanlin, BAI Naling, ZHENG Xianqing, LI Shuangxi, ZHANG Juanqin, ZHANG Haiyun, ZHOU Sheng, SUN Huifeng, LYU Weiguang
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2013 Vol. 21, No. 3
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2013, 21(3): 267-273.
doi: 10.3724/SP.J.1011.2013.00267
Abstract:
Water shortage has been identified as a critical issue of sustainability in the North China Plain, a main grain production base in China. It has directly threatened agriculture production in the region and the country at large. Wheat (Triticum aestivum L.), a major cultivated crop in the world, has become an economically viable crop in North China. Breeding drought-tolerant wheat varieties has proven to be an effective approach to limit drought losses in the region. However, inadequate genetic diversity within the Triticum family has hindered progress in developing improved drought tolerant wheat varieties. Exploitation and application of tolerant alien genes from related wheat genera and species have been achieved through distant hybridization of wheat and specific wild grasses. An entire genomic DNA injection technology delimited species barrier and made it possible to transfer exotic genes into wheat from any related or non-related species. Transgenic wheat also opened up a new era of pyramiding drought-related genes of different origins to increase drought tolerance. Using these technologies as take-off point, this paper reviewed relevant progress in wheat drought tolerance improvement.
Water shortage has been identified as a critical issue of sustainability in the North China Plain, a main grain production base in China. It has directly threatened agriculture production in the region and the country at large. Wheat (Triticum aestivum L.), a major cultivated crop in the world, has become an economically viable crop in North China. Breeding drought-tolerant wheat varieties has proven to be an effective approach to limit drought losses in the region. However, inadequate genetic diversity within the Triticum family has hindered progress in developing improved drought tolerant wheat varieties. Exploitation and application of tolerant alien genes from related wheat genera and species have been achieved through distant hybridization of wheat and specific wild grasses. An entire genomic DNA injection technology delimited species barrier and made it possible to transfer exotic genes into wheat from any related or non-related species. Transgenic wheat also opened up a new era of pyramiding drought-related genes of different origins to increase drought tolerance. Using these technologies as take-off point, this paper reviewed relevant progress in wheat drought tolerance improvement.
2013, 21(3): 274-281.
doi: 10.3724/SP.J.1011.2013.00274
Abstract:
"Gangyou 527" (hybrid indica rice) and "Nongken 57" (conventional japonica) were used to study nitrogen utilization and yield under three nitrogen fertilizers (ammonium sulfate with ammonium/nitrate ratio of 100∶0, ammonium nitrate with ammonium/nitrate ratio of 50∶50 and sodium nitrate with ammonium/nitrate ratio of 0∶100) and four water stress (soil water potential of 0 kPa, 25 kPa, 50 kPa and 75 kPa) treatments for 14 consecutive days at the grain filling stage. The results showed a significantly higher increase in rice grain yield for ammonium/nitrate ratio of 50∶50 than 100∶0 under soil water potential of 25 kPa. When the proportion of ammonium nitrogen was ≥50%, further increase in the proportion of nitrate eased the adverse effects of severe soil moisture shortage on yield formation. Increase in the proportion of nitrate under soil water potential range of 0~ 25 kPa promoted nitrogen accumulation in the rice plant; which significantly different from that of pure nitrate treatment, but not significantly from that of pure ammonium treatment. The advantage of enhanced nitrate was not so obvious when soil water potential ≤ 50 kPa. On the contrary, increased ratio of ammonium greatly enhanced production. Nitrogen absorption by the rice plant before tillering increased with increasing proportion of ammonium nitrogen. However, appropriate increase in nitrate ratio to a certain proportion promoted growth at the mid-late stage of rice. It also enhanced the absorption rate of nitrogen and nitrogen accumulation in seed, which in turn increased nitrogen use efficiency. Moderate water stress promoted seed nitrogen absorption, promoted seed dry matter accumulation, improved grain nutrient content and enhanced grain harvest index. Yield response of hybrid indica rice "Gangyou 527" and conventional japonica rice "Nongken 57" to nitrogen utilization was basically the same under different nitrogen and water stress treatments at the grain-filling stage.
"Gangyou 527" (hybrid indica rice) and "Nongken 57" (conventional japonica) were used to study nitrogen utilization and yield under three nitrogen fertilizers (ammonium sulfate with ammonium/nitrate ratio of 100∶0, ammonium nitrate with ammonium/nitrate ratio of 50∶50 and sodium nitrate with ammonium/nitrate ratio of 0∶100) and four water stress (soil water potential of 0 kPa, 25 kPa, 50 kPa and 75 kPa) treatments for 14 consecutive days at the grain filling stage. The results showed a significantly higher increase in rice grain yield for ammonium/nitrate ratio of 50∶50 than 100∶0 under soil water potential of 25 kPa. When the proportion of ammonium nitrogen was ≥50%, further increase in the proportion of nitrate eased the adverse effects of severe soil moisture shortage on yield formation. Increase in the proportion of nitrate under soil water potential range of 0~ 25 kPa promoted nitrogen accumulation in the rice plant; which significantly different from that of pure nitrate treatment, but not significantly from that of pure ammonium treatment. The advantage of enhanced nitrate was not so obvious when soil water potential ≤ 50 kPa. On the contrary, increased ratio of ammonium greatly enhanced production. Nitrogen absorption by the rice plant before tillering increased with increasing proportion of ammonium nitrogen. However, appropriate increase in nitrate ratio to a certain proportion promoted growth at the mid-late stage of rice. It also enhanced the absorption rate of nitrogen and nitrogen accumulation in seed, which in turn increased nitrogen use efficiency. Moderate water stress promoted seed nitrogen absorption, promoted seed dry matter accumulation, improved grain nutrient content and enhanced grain harvest index. Yield response of hybrid indica rice "Gangyou 527" and conventional japonica rice "Nongken 57" to nitrogen utilization was basically the same under different nitrogen and water stress treatments at the grain-filling stage.
2013, 21(3): 282-289.
doi: 10.3724/SP.J.1011.2013.00282
Abstract:
Water and nitrogen (N) fertilizer have been identified as the two key factors that influence wheat root and shoot development. Root/shoot ratio and water use efficiency (WUE) of winter wheat were studied in the field and tub experiments at the Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences in the North China Plain. The field experiment involved with 5 irrigation treatments (with zero to 4 irrigations) during winter wheat growth period. The tub experiment involved 15 treatments of five levels of N (0 g·tub-1, 2 g·tub-1, 4 g·tub-1, 6 g·tub-1, 8 g·tub-1) and three levels of irrigation (with 140 mm, 210 mm, 280 mm irrigation), with 6 replicas of each treatment. The PVC tub used in this experiment was 1 m in depth and 20 cm in diameter. The bottom of each tub was sealed with plastic film and buried in the field. Field data showed that soil water content significantly influenced root and shoot biomass accumulation. The root/shoot ratio was not affected by irrigation when water content of the top 60 cm soil layer was above 60% of field capacity. Below this soil water level, root/shoot ratio increased with decreasing soil water content. The tub experiment showed that the root/shoot ratio was significantly driven by N dose and not by the combined effect of water and N. Root dry weight decreased and grain yield increased with increasing N dose under deficit water supply. Concurrently, WUE increased with increasing N dose. Under sufficient water supply, winter wheat yield initially increased with increasing N dose to a certain level, after which it no longer changed with increasing N dose. A threshold value for N dose was noted under sufficient water supply. While under deficit water supply, more N meant higher WUE by reduced root/shoot ratio. This study suggested that N and water regulated biomass allocation to the parts of the above-ground and below-ground systems of the plant that influenced grain production and WUE. Both experiments showed a negative correlation between root/shoot ratio and WUE. That implied that higher root/shoot ratio increased biomass allocation to root but at the same time reduced above-ground biomass and WUE.
Water and nitrogen (N) fertilizer have been identified as the two key factors that influence wheat root and shoot development. Root/shoot ratio and water use efficiency (WUE) of winter wheat were studied in the field and tub experiments at the Luancheng Agro-Ecosystem Experimental Station of Chinese Academy of Sciences in the North China Plain. The field experiment involved with 5 irrigation treatments (with zero to 4 irrigations) during winter wheat growth period. The tub experiment involved 15 treatments of five levels of N (0 g·tub-1, 2 g·tub-1, 4 g·tub-1, 6 g·tub-1, 8 g·tub-1) and three levels of irrigation (with 140 mm, 210 mm, 280 mm irrigation), with 6 replicas of each treatment. The PVC tub used in this experiment was 1 m in depth and 20 cm in diameter. The bottom of each tub was sealed with plastic film and buried in the field. Field data showed that soil water content significantly influenced root and shoot biomass accumulation. The root/shoot ratio was not affected by irrigation when water content of the top 60 cm soil layer was above 60% of field capacity. Below this soil water level, root/shoot ratio increased with decreasing soil water content. The tub experiment showed that the root/shoot ratio was significantly driven by N dose and not by the combined effect of water and N. Root dry weight decreased and grain yield increased with increasing N dose under deficit water supply. Concurrently, WUE increased with increasing N dose. Under sufficient water supply, winter wheat yield initially increased with increasing N dose to a certain level, after which it no longer changed with increasing N dose. A threshold value for N dose was noted under sufficient water supply. While under deficit water supply, more N meant higher WUE by reduced root/shoot ratio. This study suggested that N and water regulated biomass allocation to the parts of the above-ground and below-ground systems of the plant that influenced grain production and WUE. Both experiments showed a negative correlation between root/shoot ratio and WUE. That implied that higher root/shoot ratio increased biomass allocation to root but at the same time reduced above-ground biomass and WUE.
2013, 21(3): 290-296.
doi: 10.3724/SP.J.1011.2013.00290
Abstract:
Methane (CH4) and nitrous oxide (N2O) are tow potent greenhouse gases (GHGs) that have contributed to global warming. The emissions of these gases from rice paddies have been affected by several factors, including climate, soil property, water regime, fertilizers, etc. Although research has focused on CH4 and N2O emissions in rice paddies under various agro-management systems, little has been available on CH4 and N2O emissions from rice paddies under different paddy-upland crop rotation systems. To that end, a field experiment was conducted in the 2011 rice growth season to benefit scientific evaluation of GHG emissions and provide scientific strategies for developing rational measures to reduce GHGs emissions in paddy fields across China. Using static chamber/gas chromatographic techniques, the field experiment was conducted in Suzhou, Jiangsu Province simultaneously measured CH4 and N2O emissions under five paddy-upland crop rotation systems. The five systems included fallow-rice (control, CK), Chinese milk vetch-rice (T1), ryegrass-rice (T2), winter wheat-rice (T3) and rape-rice (T4). The results showed characteristics seasonal variations in CH4 emission under different paddy-upland crop rotation systems during rice growth season. Although CH4 emission initially increased, it eventually declined in the course of the rice growth season. Peak CH4 flux was during the early stage of rice growth. CH4 cumulative emission from transplanting to the critical stage of productive tillering accounted for 65%~81% of the total emission during the rice growth season. Peak N2O flux was only observed during midseason drainage period. Total CH4 and N2O emissions during the rice growth season were significantly influenced by paddy-upland crop rotation systems (P < 0.01). Total CH4 emission under different paddy-upland crop rotation systems was in following order: T1 (283.2 kg·hm 2) > CK (139.5 kg·hm2) > T3 (123.4 kg·hm2) > T4 (114.7 kg·hm2) > T2 (100.8 kg·hm2). Total N2O emission was in order of: T1 > T4 > T3 > T2 > CK, with respective means of 1.06 kg·hm2, 0.87 kg·hm2, 0.81 kg·hm2, 0.72 kg·hm2 and 0.53 kg·hm 2. Combined global warming potential (GWP) of CH4 and N2O under T1 was 7 396 kg(CO2)·hm2, significantly higher than CK, T2, T3 or T4. Compared with CK [3 646 kg(CO2)·hm2], T1 increased GWP by 103% while that of T2 [2 735 kg(CO2)·hm2] decreased by 25%. The pilot study suggested that Chinese milk vetch-rice rotation intensified greenhouse effects during rice growth season in the Taihu Lake Region.
Methane (CH4) and nitrous oxide (N2O) are tow potent greenhouse gases (GHGs) that have contributed to global warming. The emissions of these gases from rice paddies have been affected by several factors, including climate, soil property, water regime, fertilizers, etc. Although research has focused on CH4 and N2O emissions in rice paddies under various agro-management systems, little has been available on CH4 and N2O emissions from rice paddies under different paddy-upland crop rotation systems. To that end, a field experiment was conducted in the 2011 rice growth season to benefit scientific evaluation of GHG emissions and provide scientific strategies for developing rational measures to reduce GHGs emissions in paddy fields across China. Using static chamber/gas chromatographic techniques, the field experiment was conducted in Suzhou, Jiangsu Province simultaneously measured CH4 and N2O emissions under five paddy-upland crop rotation systems. The five systems included fallow-rice (control, CK), Chinese milk vetch-rice (T1), ryegrass-rice (T2), winter wheat-rice (T3) and rape-rice (T4). The results showed characteristics seasonal variations in CH4 emission under different paddy-upland crop rotation systems during rice growth season. Although CH4 emission initially increased, it eventually declined in the course of the rice growth season. Peak CH4 flux was during the early stage of rice growth. CH4 cumulative emission from transplanting to the critical stage of productive tillering accounted for 65%~81% of the total emission during the rice growth season. Peak N2O flux was only observed during midseason drainage period. Total CH4 and N2O emissions during the rice growth season were significantly influenced by paddy-upland crop rotation systems (P < 0.01). Total CH4 emission under different paddy-upland crop rotation systems was in following order: T1 (283.2 kg·hm 2) > CK (139.5 kg·hm2) > T3 (123.4 kg·hm2) > T4 (114.7 kg·hm2) > T2 (100.8 kg·hm2). Total N2O emission was in order of: T1 > T4 > T3 > T2 > CK, with respective means of 1.06 kg·hm2, 0.87 kg·hm2, 0.81 kg·hm2, 0.72 kg·hm2 and 0.53 kg·hm 2. Combined global warming potential (GWP) of CH4 and N2O under T1 was 7 396 kg(CO2)·hm2, significantly higher than CK, T2, T3 or T4. Compared with CK [3 646 kg(CO2)·hm2], T1 increased GWP by 103% while that of T2 [2 735 kg(CO2)·hm2] decreased by 25%. The pilot study suggested that Chinese milk vetch-rice rotation intensified greenhouse effects during rice growth season in the Taihu Lake Region.
2013, 21(3): 297-307.
doi: 10.3724/SP.J.1011.2013.00297
Abstract:
Comprehensive studies on greenhouse gas emissions and the related global warming potential (GWP) under different agricultural management practices had the benefits of mitigated greenhouse gas emissions, reduced GWP and strengthened theoretical basis for measurements of greenhouse gas emissions. Based on experiment with four agricultural management patterns (T1: conventional pattern; T2: high-yield and high-efficiency pattern; T3: super-high-yield pattern; T4: super-high-yield, high-efficiency and soil fertility improvement pattern), N2O, CO2 and CH4 fluxes in winter-wheat fields were monitored from October 2009 to September 2011 using the static chamber method and the gas chromatographic technique. Total greenhouse gas emissions and GWP were then accordingly estimated. The results indicated that the winter-wheat field was the sources of N2O and CO2, but the sink of CH4. The effects of the different agricultural management patterns on the different greenhouse gas sources and sinks were different. High N application and sufficient irrigation increased the CO2 and N2O in the soil and strengthened the characteristics of soil as the emission source of CO2 and N2O. Meanwhile, CH4 oxidation in soils was restrained and soil characteristics as CH4 sink decreased. The carbon equivalent of emitted greenhouse gases in treatments T1, T2, T3 and T4 in 2009-2010 were respectively 8 880 kg(CO2)·hm-2, 8 372 kg(CO2)·hm-2, 9 600 kg(CO2)·hm-2 and 9 318 kg(CO2)·hm-2; and 13 395 kg(CO2)·hm-2, 12 904 kg(CO2)·hm-2, 13 933 kg(CO2)·hm-2 and 13 189 kg(CO2)·hm-2 in 2010-2011. Differences in greenhouse gas emissions among different treatments were caused by different fertilization and irrigation managements. Straw return or non-return largely led to the differences in greenhouse gas emissions between 2009-2010 and 2010-2011. GWP was relatively low while yield and input-output ratio relatively high in T2. Treatment T2 was therefore considered the optimal management mode for winter-wheat cultivation in the North China Plain.
Comprehensive studies on greenhouse gas emissions and the related global warming potential (GWP) under different agricultural management practices had the benefits of mitigated greenhouse gas emissions, reduced GWP and strengthened theoretical basis for measurements of greenhouse gas emissions. Based on experiment with four agricultural management patterns (T1: conventional pattern; T2: high-yield and high-efficiency pattern; T3: super-high-yield pattern; T4: super-high-yield, high-efficiency and soil fertility improvement pattern), N2O, CO2 and CH4 fluxes in winter-wheat fields were monitored from October 2009 to September 2011 using the static chamber method and the gas chromatographic technique. Total greenhouse gas emissions and GWP were then accordingly estimated. The results indicated that the winter-wheat field was the sources of N2O and CO2, but the sink of CH4. The effects of the different agricultural management patterns on the different greenhouse gas sources and sinks were different. High N application and sufficient irrigation increased the CO2 and N2O in the soil and strengthened the characteristics of soil as the emission source of CO2 and N2O. Meanwhile, CH4 oxidation in soils was restrained and soil characteristics as CH4 sink decreased. The carbon equivalent of emitted greenhouse gases in treatments T1, T2, T3 and T4 in 2009-2010 were respectively 8 880 kg(CO2)·hm-2, 8 372 kg(CO2)·hm-2, 9 600 kg(CO2)·hm-2 and 9 318 kg(CO2)·hm-2; and 13 395 kg(CO2)·hm-2, 12 904 kg(CO2)·hm-2, 13 933 kg(CO2)·hm-2 and 13 189 kg(CO2)·hm-2 in 2010-2011. Differences in greenhouse gas emissions among different treatments were caused by different fertilization and irrigation managements. Straw return or non-return largely led to the differences in greenhouse gas emissions between 2009-2010 and 2010-2011. GWP was relatively low while yield and input-output ratio relatively high in T2. Treatment T2 was therefore considered the optimal management mode for winter-wheat cultivation in the North China Plain.
2013, 21(3): 308-314.
doi: 10.3724/SP.J.1011.2013.00308
Abstract:
World agriculture currently faces great challenges in producing sufficient food while minimizing negative environmental effects of crop cultivation, requiring us to rethink current agricultural production processes. Traditional agricultural systems based on local species diversity and interactions have contributed to food and livelihood security throughout the world for centuries. As human population increased, however, traditional agricultural systems faced daunting challenges in food demand and supply due to the lower economic benefits of the systems. Thus improving the productivity of traditional agricultural systems in a sustainable way has been of great concerned to producers and decision-makers. To determine the feasibility of increasing traditional agricultural productivity without corresponding increase in negative environment impacts, two experiments were conducted at a traditional rice-fish co-culture site that had been operated for over 1 200 years in southern Zhejiang Province. In the first experiment, three treatments without pesticide, including rice monoculture (RM), rice-fish co-culture (RF) and fish monoculture (FM), were compared. In addition to measured rice yield (in RM and RF), fish yield (in RF and FM), and surveyed input-output economics, focus was put on total nitrogen (TN), total phosphorus (TP), total ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) in field water. Four fish density treatments, including with target fish yields in rice-fish co-culture fields of 750 kg·hm-2 (RF750), 1 500 kg·hm-2 (RF1500), 2 250 kg·hm-2 (RF2250) and 3 000 kg·hm-2 (RF3000), were designed in the second experiment. Rice and fish yields, input and output of economics, and TN, TP, NH4+-N and COD were measured in the field water. The first experiment showed no significant difference in rice yield between RM and RF. There was also no significant difference in fish yield between RF and FM in the experiment. However, total and net income of the system were higher in RF than in RM and FM. Field water contents of TN, TP, NH4+-N and COD were not significantly different between RF and RM. The second experiment showed that rice yield, fish yield, and total and net economic output increased with increasing fish stock density and fish feed input. Increase in fish stock density increased target yield of fish by 1 500 kg·hm-2 (50%), significantly increased net income of rice-fish co-culture systems by 25.2%~101.4%, and also increased COD, TN, TP and NH4+-N content in field water. When target yield was 3 000 kg·hm -2, TP and COD contents became significantly higher than in other treatments; which enhanced risk of environmental pollution. Economic analysis indicated that target fish yield of 2 250 kg·hm-2 gave higher economic income and with little impact on field water environment.
World agriculture currently faces great challenges in producing sufficient food while minimizing negative environmental effects of crop cultivation, requiring us to rethink current agricultural production processes. Traditional agricultural systems based on local species diversity and interactions have contributed to food and livelihood security throughout the world for centuries. As human population increased, however, traditional agricultural systems faced daunting challenges in food demand and supply due to the lower economic benefits of the systems. Thus improving the productivity of traditional agricultural systems in a sustainable way has been of great concerned to producers and decision-makers. To determine the feasibility of increasing traditional agricultural productivity without corresponding increase in negative environment impacts, two experiments were conducted at a traditional rice-fish co-culture site that had been operated for over 1 200 years in southern Zhejiang Province. In the first experiment, three treatments without pesticide, including rice monoculture (RM), rice-fish co-culture (RF) and fish monoculture (FM), were compared. In addition to measured rice yield (in RM and RF), fish yield (in RF and FM), and surveyed input-output economics, focus was put on total nitrogen (TN), total phosphorus (TP), total ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) in field water. Four fish density treatments, including with target fish yields in rice-fish co-culture fields of 750 kg·hm-2 (RF750), 1 500 kg·hm-2 (RF1500), 2 250 kg·hm-2 (RF2250) and 3 000 kg·hm-2 (RF3000), were designed in the second experiment. Rice and fish yields, input and output of economics, and TN, TP, NH4+-N and COD were measured in the field water. The first experiment showed no significant difference in rice yield between RM and RF. There was also no significant difference in fish yield between RF and FM in the experiment. However, total and net income of the system were higher in RF than in RM and FM. Field water contents of TN, TP, NH4+-N and COD were not significantly different between RF and RM. The second experiment showed that rice yield, fish yield, and total and net economic output increased with increasing fish stock density and fish feed input. Increase in fish stock density increased target yield of fish by 1 500 kg·hm-2 (50%), significantly increased net income of rice-fish co-culture systems by 25.2%~101.4%, and also increased COD, TN, TP and NH4+-N content in field water. When target yield was 3 000 kg·hm -2, TP and COD contents became significantly higher than in other treatments; which enhanced risk of environmental pollution. Economic analysis indicated that target fish yield of 2 250 kg·hm-2 gave higher economic income and with little impact on field water environment.
2013, 21(3): 315-323.
doi: 10.3724/SP.J.1011.2013.00315
Abstract:
Soil and water loss in sloping croplands has been a major environmental problem across the globe. It has been reported that 28% of soil loss was from sloping croplands that account for only 7% of cultivated land areas. In other words, sloping croplands have been the primary source of runoff and sediment. It is therefore urgent to develop strategies for controlling soil and water loss on sloping croplands across the globe. Although various soil protection techniques (e.g., terrace and contour tillage) have been used in sloping croplands in recent years, the effects of these techniques on soil and water loss remained limited. Conservation tillage with grass-hedge has been effective in reducing soil and water loss in sloping croplands especially in tropical and subtropical regions. These techniques have, however, not been adequately evaluated in North China, thus, which has led to limited adoption by local farmers in this region. In this study, the effects of conservation tillage with grass-hedge on soil, water, nitrogen and phosphorus loss were evaluated under simulated rainfall (rainfall intensity of 60 mm·h-1) from farmland on slopes with 5%, 10%, 15% and 20% gradients in the Changping District of Beijing, China. The results showed that conservation tillage with grass-hedge significantly limited soil, water, nitrogen and phosphorus loss and in the order as follows: conservation tillage with grass-hedge > conventional tillage with grass-hedge > conservation tillage without grass-hedge > conventional tillage without grass-hedge. Runoff under conventional tillage with grass-hedge, conservation tillage without grass-hedge, and conservation tillage with grass-hedge decreased by 56%, 44% and 68%, respectively, compared with conventional tillage without grass-hedge. Correspondingly, soil loss decreased by 66%, 49% and 82%; total nitrogen loss dropped by 56%, 43% and 66%; and total phosphorus decreased by 54%, 40% and 70%, respectively. These results suggested that the integration of conservation tillage and grass-hedge was more effective than sole application of either conservation tillage or grass-hedges in terms of soil, water and nutrient loss control. The results further showed that the effectiveness of conservation tillage and grass-hedge gradually decreased with increasing slope gradient. Although the results suggested that both conservation tillage and grass-hedge significantly limited soil and water loss, their effectiveness was limited under steep slope conditions. Some other engineering techniques (e.g., micro-basin, fish-scale pit, mulch or even landscape shaping) therefore needed to be used in combination in order to prevent soil and water loss under steep slope and intense rain conditions. It was, however, concluded that conservation tillage and grass-hedge were critical for controlled soil, water, nitrogen and phosphorus loss in sloping croplands. These finding was useful in the remediation of soil and water loss in sloping croplands in northern China and other similar landscape regions.
Soil and water loss in sloping croplands has been a major environmental problem across the globe. It has been reported that 28% of soil loss was from sloping croplands that account for only 7% of cultivated land areas. In other words, sloping croplands have been the primary source of runoff and sediment. It is therefore urgent to develop strategies for controlling soil and water loss on sloping croplands across the globe. Although various soil protection techniques (e.g., terrace and contour tillage) have been used in sloping croplands in recent years, the effects of these techniques on soil and water loss remained limited. Conservation tillage with grass-hedge has been effective in reducing soil and water loss in sloping croplands especially in tropical and subtropical regions. These techniques have, however, not been adequately evaluated in North China, thus, which has led to limited adoption by local farmers in this region. In this study, the effects of conservation tillage with grass-hedge on soil, water, nitrogen and phosphorus loss were evaluated under simulated rainfall (rainfall intensity of 60 mm·h-1) from farmland on slopes with 5%, 10%, 15% and 20% gradients in the Changping District of Beijing, China. The results showed that conservation tillage with grass-hedge significantly limited soil, water, nitrogen and phosphorus loss and in the order as follows: conservation tillage with grass-hedge > conventional tillage with grass-hedge > conservation tillage without grass-hedge > conventional tillage without grass-hedge. Runoff under conventional tillage with grass-hedge, conservation tillage without grass-hedge, and conservation tillage with grass-hedge decreased by 56%, 44% and 68%, respectively, compared with conventional tillage without grass-hedge. Correspondingly, soil loss decreased by 66%, 49% and 82%; total nitrogen loss dropped by 56%, 43% and 66%; and total phosphorus decreased by 54%, 40% and 70%, respectively. These results suggested that the integration of conservation tillage and grass-hedge was more effective than sole application of either conservation tillage or grass-hedges in terms of soil, water and nutrient loss control. The results further showed that the effectiveness of conservation tillage and grass-hedge gradually decreased with increasing slope gradient. Although the results suggested that both conservation tillage and grass-hedge significantly limited soil and water loss, their effectiveness was limited under steep slope conditions. Some other engineering techniques (e.g., micro-basin, fish-scale pit, mulch or even landscape shaping) therefore needed to be used in combination in order to prevent soil and water loss under steep slope and intense rain conditions. It was, however, concluded that conservation tillage and grass-hedge were critical for controlled soil, water, nitrogen and phosphorus loss in sloping croplands. These finding was useful in the remediation of soil and water loss in sloping croplands in northern China and other similar landscape regions.
2013, 21(3): 324-332.
doi: 10.3724/SP.J.1011.2013.00324
Abstract:
Vegetation communities have been noted to affect soil organic carbon content via the addition of outer soil organic matter that in turn contribute to the formation of soil aggregates. The fractions of organic carbon in soil aggregates under different vegetation communities (forest and steppe zones) in the hill-gully region on the Loess Plateau were studied in this paper to explore the effect of different vegetation communities on soil structure. The study showed that: (1) Total soil organic carbon content in the forest zone of the study area was higher than that in the steppe zone. The order of total organic carbon for the plant communities in the forest zone was: Quercus liaotungensis community > Robinia pseudoacacia community > Sophora viciifolia community. Also the order of total organic carbon for the plant communities in the steppe zone was: Hippophae rhamnoides community > Lespedeza davurica + Artemisia giraldii community > Artemisia sacrorum + L. davurica community. (2) The proportions of active to total organic carbon and that of humus to total organic carbon were similar under each vegetation zone. However, the proportion of active to total organic carbon was greater than that of humus to total organic carbon under each vegetation community. (3) The >0.25 mm aggregates under the forest zone was significantly higher than that under the steppe zone. The pattern of the various forms of organic matter in the soil particles suggested initial increase in organic carbon, followed by decrease or flat curve with increasing aggregate size. A large proportion of soil organic carbon existed in 2~0.25 mm and <0.25 mm aggregates. (4) Active organic carbon content was significantly spatially different under the steppe zone. Each form of organic carbon in the Q. liaotungensis community was also significantly spatially different. The <0.25 mm aggregate humus was greater than other aggregates in the Q. liaotungensis community. (5) Unlike the other vegetation communities, there was no significant difference in terms of soil organic carbon between the 0~10 cm and 10~20 cm soil layers in the H. rhamnoides community.
Vegetation communities have been noted to affect soil organic carbon content via the addition of outer soil organic matter that in turn contribute to the formation of soil aggregates. The fractions of organic carbon in soil aggregates under different vegetation communities (forest and steppe zones) in the hill-gully region on the Loess Plateau were studied in this paper to explore the effect of different vegetation communities on soil structure. The study showed that: (1) Total soil organic carbon content in the forest zone of the study area was higher than that in the steppe zone. The order of total organic carbon for the plant communities in the forest zone was: Quercus liaotungensis community > Robinia pseudoacacia community > Sophora viciifolia community. Also the order of total organic carbon for the plant communities in the steppe zone was: Hippophae rhamnoides community > Lespedeza davurica + Artemisia giraldii community > Artemisia sacrorum + L. davurica community. (2) The proportions of active to total organic carbon and that of humus to total organic carbon were similar under each vegetation zone. However, the proportion of active to total organic carbon was greater than that of humus to total organic carbon under each vegetation community. (3) The >0.25 mm aggregates under the forest zone was significantly higher than that under the steppe zone. The pattern of the various forms of organic matter in the soil particles suggested initial increase in organic carbon, followed by decrease or flat curve with increasing aggregate size. A large proportion of soil organic carbon existed in 2~0.25 mm and <0.25 mm aggregates. (4) Active organic carbon content was significantly spatially different under the steppe zone. Each form of organic carbon in the Q. liaotungensis community was also significantly spatially different. The <0.25 mm aggregate humus was greater than other aggregates in the Q. liaotungensis community. (5) Unlike the other vegetation communities, there was no significant difference in terms of soil organic carbon between the 0~10 cm and 10~20 cm soil layers in the H. rhamnoides community.
2013, 21(3): 333-339.
doi: 10.3724/SP.J.1011.2013.00333
Abstract:
Orobanche aegyptiaca is a national-class quarantine species in China which is seriously harmful to melons and other economic crops. In this study, four commercial potato varieties ("Xiabodi", "Qingshu 168", "Jizhangshu No.5" and "Kexin No.1") were planted at a pot experiment, and their rhizosphere soils and plant organs (roots, stems and leaves) sampled at different growth stages (seedling, blossoming and tuber forming stages). Allelopathy potential of extracts (methanol and distilled water) of the above samples was measured in terms of germination rates of O. aegyptiaca seeds treated. The potatoes varieties with O. aegyptiaca seed high germination rates were chosen to prevent and kill off O. aegyptiaca seeds on croplands. The results showed that potato stimulated O. aegyptiaca germination, and the allelopathy potential differed with potato variety. The germination rates of O. aegyptiaca seeds treated with extracts of potato rhizosphere soil increased with potato growth. This suggested that potato secreted O. aegyptiaca germination stimulants at certain period of growth which in turn reduced O. aegyptiaca seed bank in the soil. At seedling stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from potato roots was higher than those from the shoot system. Seeds treated with "Xiabodi" showed the highest germination rate (48.5%). At blossoming stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from stems was highest, followed by those treated with root extracts and leaf extracts. Seeds treated with "Jizhangshu No.5" had the highest germination rate (33.0%). At tuber forming stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from shoot system was higher than those from roots. Also seeds treated with "Xiabodi" gave the highest germination rate (51.2%). While the germination rate of O. aegyptiaca seeds treated with root extracts declined with increasing growth of potato, those treated with aerial part extract increased. This suggested that of O. aegyptiaca germination stimulants in potatoes gradually moved from the root to shoot system. The germination rate of O. aegyptiaca seeds induced by methanol extracts was higher than that induced by water extracts. In other words, methanol extracts had better effects as germination stimulants. Although artificially synthesized analogues had facilitated the germination of parasitic plant seeds, government protocols had limited their field application and dissemination. Other methods for controlling O. aegyptiaca seeds (e.g., artificial weeding, herbicide application, hybridization and transgenic method) for broomrape resistant cultivars had some disadvantages. Using potato to control O. aegyptiaca was therefore a promising strategy that not only reduced and eradicated parasitic weed seed deposition in soils, but also significantly reduced host broomrape damages. Root methanol extracts of "Xiabodi" at seedling stage induced higher germination rate (48.5%) of O. aegyptiaca seeds than other potato varieties. The parts from the shoot system at tuber formation stage also induced the highest germination rate (51.2%) of O. aegyptiaca seeds. Thus among the four potato varieties, "Xiabodi" had the highest allelopathic potential on O. aegyptiaca. Since potato was reproducible from tuber and reasonable quantities were obtainable in a short time, crop rotation was an adoptable method in areas with serious O. aegyptiaca damages. Specifically, "Xiabodi" has been planted for 5~8 years with returning straw to soil to not only reduce O. aegyptiaca seed bank in the soil, but also minimize O. aegyptiaca damages.
Orobanche aegyptiaca is a national-class quarantine species in China which is seriously harmful to melons and other economic crops. In this study, four commercial potato varieties ("Xiabodi", "Qingshu 168", "Jizhangshu No.5" and "Kexin No.1") were planted at a pot experiment, and their rhizosphere soils and plant organs (roots, stems and leaves) sampled at different growth stages (seedling, blossoming and tuber forming stages). Allelopathy potential of extracts (methanol and distilled water) of the above samples was measured in terms of germination rates of O. aegyptiaca seeds treated. The potatoes varieties with O. aegyptiaca seed high germination rates were chosen to prevent and kill off O. aegyptiaca seeds on croplands. The results showed that potato stimulated O. aegyptiaca germination, and the allelopathy potential differed with potato variety. The germination rates of O. aegyptiaca seeds treated with extracts of potato rhizosphere soil increased with potato growth. This suggested that potato secreted O. aegyptiaca germination stimulants at certain period of growth which in turn reduced O. aegyptiaca seed bank in the soil. At seedling stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from potato roots was higher than those from the shoot system. Seeds treated with "Xiabodi" showed the highest germination rate (48.5%). At blossoming stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from stems was highest, followed by those treated with root extracts and leaf extracts. Seeds treated with "Jizhangshu No.5" had the highest germination rate (33.0%). At tuber forming stage of potato, the germination rate of O. aegyptiaca seeds treated with 10-fold diluted methanol extracts from shoot system was higher than those from roots. Also seeds treated with "Xiabodi" gave the highest germination rate (51.2%). While the germination rate of O. aegyptiaca seeds treated with root extracts declined with increasing growth of potato, those treated with aerial part extract increased. This suggested that of O. aegyptiaca germination stimulants in potatoes gradually moved from the root to shoot system. The germination rate of O. aegyptiaca seeds induced by methanol extracts was higher than that induced by water extracts. In other words, methanol extracts had better effects as germination stimulants. Although artificially synthesized analogues had facilitated the germination of parasitic plant seeds, government protocols had limited their field application and dissemination. Other methods for controlling O. aegyptiaca seeds (e.g., artificial weeding, herbicide application, hybridization and transgenic method) for broomrape resistant cultivars had some disadvantages. Using potato to control O. aegyptiaca was therefore a promising strategy that not only reduced and eradicated parasitic weed seed deposition in soils, but also significantly reduced host broomrape damages. Root methanol extracts of "Xiabodi" at seedling stage induced higher germination rate (48.5%) of O. aegyptiaca seeds than other potato varieties. The parts from the shoot system at tuber formation stage also induced the highest germination rate (51.2%) of O. aegyptiaca seeds. Thus among the four potato varieties, "Xiabodi" had the highest allelopathic potential on O. aegyptiaca. Since potato was reproducible from tuber and reasonable quantities were obtainable in a short time, crop rotation was an adoptable method in areas with serious O. aegyptiaca damages. Specifically, "Xiabodi" has been planted for 5~8 years with returning straw to soil to not only reduce O. aegyptiaca seed bank in the soil, but also minimize O. aegyptiaca damages.
2013, 21(3): 340-346.
doi: 10.3724/SP.J.1011.2013.00340
Abstract:
Ecological environment and agricultural sustainability in present days China have been threatened by soil salinity. Plant roots have been the first to feel adverse soil stress conditions through different physiological processes. Study of alfalfa response to salt stress has mainly focused on the above-ground system or on the growth and physiological response to single salt stress. Alfalfa root response to complex saline-alkali stress has been rarely reported. The primary aim of this study was to determine the response of alfalfa root to saline-alkali conditions. The study also explored alfalfa growth and adaptation characteristics under complex saline-alkali stress conditions and provided theoretical bases for alfalfa cultivation in saline-alkali field. The Medicago sativa L. cv. "Gannong No.3" was investigated under complex saline-alkali stress conditions at seeding growth stage. 20 different alkali-saline stress conditions simulated saline-alkali soil conditions obtained by mixing two neutral (NaCl and Na2SO4) and alkaline (NaHCO3 and Na2SO3) salts in different proportions [A (NaCl︰Na2SO4 in 1︰1 ratio), B (NaCl︰Na2SO3 in 1︰1 ratio), C (NaCl︰Na2SO4︰NaHCO3︰Na2SO3 in 1︰1︰1︰1 ratio), D (Na2SO4︰Na2SO3 in 1︰1 ratio) and E (NaHCO3︰Na2SO3 in 1︰1 ratio)] and concentrations (25 mmol·L-1, 50 mmol·L-1, 100 mmol·L-1 and 150 mmol·L-1). To understand alfalfa root growth characteristics in mixed salt stress conditions, total root length, root surface area, average root diameter, root volume and root tip number were analyzed. The results showed that salt concentration was the main driving factor of alfalfa root growth. There was obvious negative effect of the saline-alkali conditions on root tip number and insignificant effect on average root diameter. As treatment concentration increased, total root length and root surface area initially increased followed by a decrease. At low concentration of ≤50 mmol·L-1, total root length under A (25 mmol·L-1) and B (50 mmol·L -1) treatments respectively increased by 50.7% and 37.9% over CK (0 mmol·L -1). At a concentration of 150 mmol·L -1, total root length under treatments A, B, C, D and E respectively dropped by 26.6%, 37.7%, 51.6%, 37.0% and 55.7% compared with CK; all of which were significantly lower than the CK. Root surface area under treatments A, C and D increased at 25 mmol·L-1 concentration by 21.1%, 43.4% and 12.7% over CK. At 150 mmol·L -1 concentration, root surface area under treatment E dropped by 49.6% over CK. This suggested that low saline-alkali stress (≤50 mmol·L-1) conditions promoted or insignificantly influenced alfalfa seedling root growth. However, high saline-alkali stress (≥50 mmol·L -1) conditions inhibited alfalfa seedling root growth. Increasing alkaline salt under high salt concentration increased alfalfa root growth inhibition.
Ecological environment and agricultural sustainability in present days China have been threatened by soil salinity. Plant roots have been the first to feel adverse soil stress conditions through different physiological processes. Study of alfalfa response to salt stress has mainly focused on the above-ground system or on the growth and physiological response to single salt stress. Alfalfa root response to complex saline-alkali stress has been rarely reported. The primary aim of this study was to determine the response of alfalfa root to saline-alkali conditions. The study also explored alfalfa growth and adaptation characteristics under complex saline-alkali stress conditions and provided theoretical bases for alfalfa cultivation in saline-alkali field. The Medicago sativa L. cv. "Gannong No.3" was investigated under complex saline-alkali stress conditions at seeding growth stage. 20 different alkali-saline stress conditions simulated saline-alkali soil conditions obtained by mixing two neutral (NaCl and Na2SO4) and alkaline (NaHCO3 and Na2SO3) salts in different proportions [A (NaCl︰Na2SO4 in 1︰1 ratio), B (NaCl︰Na2SO3 in 1︰1 ratio), C (NaCl︰Na2SO4︰NaHCO3︰Na2SO3 in 1︰1︰1︰1 ratio), D (Na2SO4︰Na2SO3 in 1︰1 ratio) and E (NaHCO3︰Na2SO3 in 1︰1 ratio)] and concentrations (25 mmol·L-1, 50 mmol·L-1, 100 mmol·L-1 and 150 mmol·L-1). To understand alfalfa root growth characteristics in mixed salt stress conditions, total root length, root surface area, average root diameter, root volume and root tip number were analyzed. The results showed that salt concentration was the main driving factor of alfalfa root growth. There was obvious negative effect of the saline-alkali conditions on root tip number and insignificant effect on average root diameter. As treatment concentration increased, total root length and root surface area initially increased followed by a decrease. At low concentration of ≤50 mmol·L-1, total root length under A (25 mmol·L-1) and B (50 mmol·L -1) treatments respectively increased by 50.7% and 37.9% over CK (0 mmol·L -1). At a concentration of 150 mmol·L -1, total root length under treatments A, B, C, D and E respectively dropped by 26.6%, 37.7%, 51.6%, 37.0% and 55.7% compared with CK; all of which were significantly lower than the CK. Root surface area under treatments A, C and D increased at 25 mmol·L-1 concentration by 21.1%, 43.4% and 12.7% over CK. At 150 mmol·L -1 concentration, root surface area under treatment E dropped by 49.6% over CK. This suggested that low saline-alkali stress (≤50 mmol·L-1) conditions promoted or insignificantly influenced alfalfa seedling root growth. However, high saline-alkali stress (≥50 mmol·L -1) conditions inhibited alfalfa seedling root growth. Increasing alkaline salt under high salt concentration increased alfalfa root growth inhibition.
2013, 21(3): 347-355.
doi: 10.3724/SP.J.1011.2013.00347
Abstract:
To make full use of salt water resources in minimizing the severity of scarcity of fresh water resources in the Low Hebei Plain, the impacts of salt water irrigation on wheat yield and selected leaf physiological indices were analyzed. The indices included relative electrical conductivity, MDA (malondialdehyde) content, Pro (proline) content, and concentrations of K+, Ca2+ and Na+, as well as K+/Na+ ratio. And their relationships with salt tolerance of wheat varieties were discussed too. The analysis was based on data from a long-term field trial of salt water irrigation. In the trial, the split-plot design was used with irrigation water salinity as main plots and wheat variety the sub-plots. The results showed that cell membrane permeability, MDA content, Pro content and Na+ concentration increased in leaves with increasing salinity of irrigation water. However, K+/Na+ ratio and Ca2+ concentration declined for increasing salinity treatments. Based on yield and salt tolerance index analysis, the "Shijiazhuang 8" variety was more salt-tolerant than "Heng 4399". For the physiological indices, "Shijiazhuang 8" cell membrane was more stable than "Heng 4399" cell membrane. For "Heng 4399", membrane permeability increased sharply at a irrigation water salinity of 2 g·L-1. Sharp increase in membrane permeability of "Shijiazhuang 8" was only noted at a irrigation water salinity of 4 g·L-. In comparison with "Heng 4399", salt tolerance characteristics of "Shijiazhuang 8" were related to its ability to maintain higher levels of K+ and K+/Na+ and lower levels of Pro, however, it was less related with Na+ and Ca2+ concentrations. For MDA level, "Shijiazhuang 8" was lower during reviving and booting periods compared with "Heng 4399", but higher during heading and milking periods. Yields of both "Shijiazhuang 8" and "Heng 4399" decreased significantly when irrigation water salinity was above 4 g·L-1, but the decrease was always less in "Shijiazhuang 8" than in "Heng 4399" under similar treatments. With the continuous use of saline water irrigation, it was necessary to keep irrigation water salinity under 4 g·L-1. Also choosing salt tolerant varieties was very critical for high harvest in the Low Hebei Plain.
To make full use of salt water resources in minimizing the severity of scarcity of fresh water resources in the Low Hebei Plain, the impacts of salt water irrigation on wheat yield and selected leaf physiological indices were analyzed. The indices included relative electrical conductivity, MDA (malondialdehyde) content, Pro (proline) content, and concentrations of K+, Ca2+ and Na+, as well as K+/Na+ ratio. And their relationships with salt tolerance of wheat varieties were discussed too. The analysis was based on data from a long-term field trial of salt water irrigation. In the trial, the split-plot design was used with irrigation water salinity as main plots and wheat variety the sub-plots. The results showed that cell membrane permeability, MDA content, Pro content and Na+ concentration increased in leaves with increasing salinity of irrigation water. However, K+/Na+ ratio and Ca2+ concentration declined for increasing salinity treatments. Based on yield and salt tolerance index analysis, the "Shijiazhuang 8" variety was more salt-tolerant than "Heng 4399". For the physiological indices, "Shijiazhuang 8" cell membrane was more stable than "Heng 4399" cell membrane. For "Heng 4399", membrane permeability increased sharply at a irrigation water salinity of 2 g·L-1. Sharp increase in membrane permeability of "Shijiazhuang 8" was only noted at a irrigation water salinity of 4 g·L-. In comparison with "Heng 4399", salt tolerance characteristics of "Shijiazhuang 8" were related to its ability to maintain higher levels of K+ and K+/Na+ and lower levels of Pro, however, it was less related with Na+ and Ca2+ concentrations. For MDA level, "Shijiazhuang 8" was lower during reviving and booting periods compared with "Heng 4399", but higher during heading and milking periods. Yields of both "Shijiazhuang 8" and "Heng 4399" decreased significantly when irrigation water salinity was above 4 g·L-1, but the decrease was always less in "Shijiazhuang 8" than in "Heng 4399" under similar treatments. With the continuous use of saline water irrigation, it was necessary to keep irrigation water salinity under 4 g·L-1. Also choosing salt tolerant varieties was very critical for high harvest in the Low Hebei Plain.
2013, 21(3): 356-364.
doi: 10.3724/SP.J.1011.2013.00356
Abstract:
To explore the mechanism of heavy metal metabolism in plants under heavy metal stress, maize tolerance to cadmium (Cd) was investigated as a test case. Maize seedling was germinated under different Cd concentrations (5~100 μmol·L-1) and the processing time was studied. The parameters of maize seedling, Cd content and distribution in different tissues, High Performance Liquid Chromatography-Mass Spectrometry spectra (HPLC-MS), Nuclear Magnetic Resonance spectra (1H NMR) and amino acids contents were investigated. The results showed that under Cd stress <50 μmol·L-1, maize germination was significantly enhanced. When, however, Cd stress exceeded 50 μmol·L-1, maize germination was inhibited. Cd was unevenly distributed in the fresh endosperm, root, stem and bud tissues in the order of endosperm > radicle > stem > burgeon. HPLC-MS and 1H NMR analyses indicated Cd chelation in maize in the form of phytochelatin (PC). Total protein amino acid content analysis showed that nutrient absorption and synthesis were to some extent affected by Cd stress. Cd accumulation and transmission process in maize seedling was such that while a large amount of Cd was adsorbed on maize endosperm, limited Cd was directly adsorbed on radicle surface. Cd existed in both free and phytochelatin forms in the maize plant. Cd interacted with various cell proteins and was transmitted among cytosol, vacuole, cell plasmodesmata and other seedling organelles. Cd was transmitted to burgeon through the radicle and stem and the transfer process was driven mainly by concentration gradient. The process likely followed along a concentration gradient facilitated by diffusion, and the rationality of which was proven by the experiment.
To explore the mechanism of heavy metal metabolism in plants under heavy metal stress, maize tolerance to cadmium (Cd) was investigated as a test case. Maize seedling was germinated under different Cd concentrations (5~100 μmol·L-1) and the processing time was studied. The parameters of maize seedling, Cd content and distribution in different tissues, High Performance Liquid Chromatography-Mass Spectrometry spectra (HPLC-MS), Nuclear Magnetic Resonance spectra (1H NMR) and amino acids contents were investigated. The results showed that under Cd stress <50 μmol·L-1, maize germination was significantly enhanced. When, however, Cd stress exceeded 50 μmol·L-1, maize germination was inhibited. Cd was unevenly distributed in the fresh endosperm, root, stem and bud tissues in the order of endosperm > radicle > stem > burgeon. HPLC-MS and 1H NMR analyses indicated Cd chelation in maize in the form of phytochelatin (PC). Total protein amino acid content analysis showed that nutrient absorption and synthesis were to some extent affected by Cd stress. Cd accumulation and transmission process in maize seedling was such that while a large amount of Cd was adsorbed on maize endosperm, limited Cd was directly adsorbed on radicle surface. Cd existed in both free and phytochelatin forms in the maize plant. Cd interacted with various cell proteins and was transmitted among cytosol, vacuole, cell plasmodesmata and other seedling organelles. Cd was transmitted to burgeon through the radicle and stem and the transfer process was driven mainly by concentration gradient. The process likely followed along a concentration gradient facilitated by diffusion, and the rationality of which was proven by the experiment.
2013, 21(3): 365-374.
doi: 10.3724/SP.J.1011.2013.00365
Abstract:
As a major starch-based raw material for fuel ethanol production, sweet potato [Ipomoea batatas (L.) Lam.] is a critical industrial material and a new energy resource. The development of new sweet potato varieties with high starch yield has been a key element of sweet potato research. To improve breeding efficiency of sweet potato varieties with high starch yield, short breeding cycle and valuable index supply for early selection of high starch yield sweet potato breed, this study used the Unweighted Pair Group and PSC- (Pair Similarity Coefficient) based Arithmetic Average Method to classify 48 main sweet potato germplasm resources in terms of starch yield, morphological traits and synthetic enzyme activity. Then correlation analysis was used to assess the relations of starch yield with agronomic traits and starch synthetic enzyme activity at different times. The results showed significant variations in agronomic traits of different sweet potato varieties/lines and periods. Cluster results indicated that agronomic traits in 100 days after planting were most relevant with starch yield. Among the agronomic traits, starch yield was significantly negatively correlated with plant branch (r = 0.428) and significantly positively correlated with dry matter rate (r = 0.423) in 100 days after planting. No significant correlation existed between starch yield and maximum vine length, root tuber number per plant or root tuber fresh weight per plant. It was possible to use plant branch and dry matter in 100 days after planting as indexes in early selection of high starch yield sweet potato breed. The cluster results for key starch synthesis enzymes (ADPG-PPase, SS and SPS) activities at different times were significantly different. The cluster results showed key starch synthesis enzymes activities in 50 days after planting was most relevant with starch yield. Among the enzymes activities in 50 days after planting, starch yield was negatively correlated with ADPG-PPase activity (r = 0.163), and positively correlated with SS (r = 0.101) and SPS (r = 0.016) activities; all of which were insignificant. Because of the weak correlation and tedious determination process, it was not possible to use the activities of ADPG-PPase, SS and SPS as physiological indexes in early selection of high starch yield sweet potato breed. Results of the starch yield and agronomic traits analyses provided valuable reference for screening breeding materials in developing new high starch yield varieties. On the basis of existing studies on agronomic traits, it was possible to use high dry matter rate and lower plant branch within 100 days after planting as reference indexes in early generation in breeding sweet potato high starch yield varieties.
As a major starch-based raw material for fuel ethanol production, sweet potato [Ipomoea batatas (L.) Lam.] is a critical industrial material and a new energy resource. The development of new sweet potato varieties with high starch yield has been a key element of sweet potato research. To improve breeding efficiency of sweet potato varieties with high starch yield, short breeding cycle and valuable index supply for early selection of high starch yield sweet potato breed, this study used the Unweighted Pair Group and PSC- (Pair Similarity Coefficient) based Arithmetic Average Method to classify 48 main sweet potato germplasm resources in terms of starch yield, morphological traits and synthetic enzyme activity. Then correlation analysis was used to assess the relations of starch yield with agronomic traits and starch synthetic enzyme activity at different times. The results showed significant variations in agronomic traits of different sweet potato varieties/lines and periods. Cluster results indicated that agronomic traits in 100 days after planting were most relevant with starch yield. Among the agronomic traits, starch yield was significantly negatively correlated with plant branch (r = 0.428) and significantly positively correlated with dry matter rate (r = 0.423) in 100 days after planting. No significant correlation existed between starch yield and maximum vine length, root tuber number per plant or root tuber fresh weight per plant. It was possible to use plant branch and dry matter in 100 days after planting as indexes in early selection of high starch yield sweet potato breed. The cluster results for key starch synthesis enzymes (ADPG-PPase, SS and SPS) activities at different times were significantly different. The cluster results showed key starch synthesis enzymes activities in 50 days after planting was most relevant with starch yield. Among the enzymes activities in 50 days after planting, starch yield was negatively correlated with ADPG-PPase activity (r = 0.163), and positively correlated with SS (r = 0.101) and SPS (r = 0.016) activities; all of which were insignificant. Because of the weak correlation and tedious determination process, it was not possible to use the activities of ADPG-PPase, SS and SPS as physiological indexes in early selection of high starch yield sweet potato breed. Results of the starch yield and agronomic traits analyses provided valuable reference for screening breeding materials in developing new high starch yield varieties. On the basis of existing studies on agronomic traits, it was possible to use high dry matter rate and lower plant branch within 100 days after planting as reference indexes in early generation in breeding sweet potato high starch yield varieties.
2013, 21(3): 375-385.
doi: 10.3724/SP.J.1011.2013.00375
Abstract:
Fruit number per plant (FNP) is an important yield component of tomato plants. To quantitatively analyze the relationship between FNP of different protected tomato varieties and local environmental conditions, field experiments were carried out in Suoshi Village, Nanjing, in 2009, 2010, and 2011, respectively, involving tomato varieties and fertilizer and water uses. The "American mole 1" (B1, early maturing), "Chaoshijifanqiedawang" (B2, late maturing), and "American 903" (B3, medium maturing) tomato varieties were adopted as experimental materials in the study. In accordance with the processes of dynamic balance and self-regulation of buds, flowers, and fruit number per plant of various protected tomatoes varieties, the flower and fruit abscission number, bud number per plant, and FNP models were built by analyzing the relationships among the number of bud, flower abscission, fruit abscission, FNP, and local environmental factors. The effects of temperature, light, nitrogen, and water were introduced into the developed models. The models were validated using independent experimental datasets. The results showed the root mean squared error (RMSE), mean absolute error (Xde), and determinant coefficient (R2) for the simulated and measured values of bud number per plant to be 2.452 (n=24), 1.851, and 0.976 for B1; 1.820 (n=24), 1.422, and 0.948 for B2; and 1.849 (n=24), 1.464, and 0.949 for B3; respectively. Also the RMSE, Xde and R2 for flower abscission number per plant were 0.712 (n=16), 0.662, and 0.786 for B1; 0.730 (n=17), 0.662, and 0.965 for B2; and 1.229 (n=16), 1.091, and 0.952 for B3; respectively. The RMSE, Xde, and R2 for fruit abscission number per plant were 0.391 (n=15), 0.342, and 0.849 for B1; 0.439 (n=15), 0.346, and 0.966 for B2; and 0.318 (n=15), 0.288, and 0.961 for B3; respectively. Then the RMSE, Xde, and R2 for FNP were 0.839 (n=27), 0.712, and 0.934, respectively. It was noted that the simulated values agreed well with the measured ones. This suggested that FNP of different protected tomato varieties under different water and fertilizer conditions were well simulated by the developed models in this study.
Fruit number per plant (FNP) is an important yield component of tomato plants. To quantitatively analyze the relationship between FNP of different protected tomato varieties and local environmental conditions, field experiments were carried out in Suoshi Village, Nanjing, in 2009, 2010, and 2011, respectively, involving tomato varieties and fertilizer and water uses. The "American mole 1" (B1, early maturing), "Chaoshijifanqiedawang" (B2, late maturing), and "American 903" (B3, medium maturing) tomato varieties were adopted as experimental materials in the study. In accordance with the processes of dynamic balance and self-regulation of buds, flowers, and fruit number per plant of various protected tomatoes varieties, the flower and fruit abscission number, bud number per plant, and FNP models were built by analyzing the relationships among the number of bud, flower abscission, fruit abscission, FNP, and local environmental factors. The effects of temperature, light, nitrogen, and water were introduced into the developed models. The models were validated using independent experimental datasets. The results showed the root mean squared error (RMSE), mean absolute error (Xde), and determinant coefficient (R2) for the simulated and measured values of bud number per plant to be 2.452 (n=24), 1.851, and 0.976 for B1; 1.820 (n=24), 1.422, and 0.948 for B2; and 1.849 (n=24), 1.464, and 0.949 for B3; respectively. Also the RMSE, Xde and R2 for flower abscission number per plant were 0.712 (n=16), 0.662, and 0.786 for B1; 0.730 (n=17), 0.662, and 0.965 for B2; and 1.229 (n=16), 1.091, and 0.952 for B3; respectively. The RMSE, Xde, and R2 for fruit abscission number per plant were 0.391 (n=15), 0.342, and 0.849 for B1; 0.439 (n=15), 0.346, and 0.966 for B2; and 0.318 (n=15), 0.288, and 0.961 for B3; respectively. Then the RMSE, Xde, and R2 for FNP were 0.839 (n=27), 0.712, and 0.934, respectively. It was noted that the simulated values agreed well with the measured ones. This suggested that FNP of different protected tomato varieties under different water and fertilizer conditions were well simulated by the developed models in this study.
2013, 21(3): 386-392.
doi: 10.3724/SP.J.1011.2013.00386
Abstract:
To determine the distribution characteristics of landscape patterns in mountain regions, the case of Qixia City was investigated and a geological database built for grid datum using the 2003/2010 land use/landscape pattern map, DEM map, soil map, etc. of Qixia City. These data were processed in ARCGIS and CANOCO environments on Windows 4.5 platform. CCA (canonical correlation analysis) ranking method was used in the study to comparatively analyze changes in landscape pattern and environmental factors in different years in Qixia City. The results showed that percent cumulative variances of landscape-environment relation were respectively 98.8% and 98.7% in 2003 and 2010, indicating a decreasing trend. However, correlation analysis between landscape and environment showed a higher coefficient for 2003 than for 2010. Meanwhile total eigen-values of the ordination axes were 0.572 and 0.808, respectively. Different environmental factors had different impacts on landscape pattern with time. There was little change in land use/landscape pattern between 2003 and 2010. In addition, the other six land use types were not obviously different, except for unused land. There were similar regularities in the relationship between landscape pattern and environmental factors for 2003 and 2010. The main factors with major impact on landscape were sunshine hours, slope gradient and altitude. Water surface and build-up land were in areas with higher sunshine hours, lower altitudes and gentler slopes. However, unused land and grassland were mainly in the other areas. Through land use/landscape pattern and environmental factor relationship, this paper determined land use/landscape pattern distribution characteristics in Qixia City. This study therefore provided theoretical basis for adjustments in agricultural land structure and in the general land use structure for optimized land use in the study area and beyond.
To determine the distribution characteristics of landscape patterns in mountain regions, the case of Qixia City was investigated and a geological database built for grid datum using the 2003/2010 land use/landscape pattern map, DEM map, soil map, etc. of Qixia City. These data were processed in ARCGIS and CANOCO environments on Windows 4.5 platform. CCA (canonical correlation analysis) ranking method was used in the study to comparatively analyze changes in landscape pattern and environmental factors in different years in Qixia City. The results showed that percent cumulative variances of landscape-environment relation were respectively 98.8% and 98.7% in 2003 and 2010, indicating a decreasing trend. However, correlation analysis between landscape and environment showed a higher coefficient for 2003 than for 2010. Meanwhile total eigen-values of the ordination axes were 0.572 and 0.808, respectively. Different environmental factors had different impacts on landscape pattern with time. There was little change in land use/landscape pattern between 2003 and 2010. In addition, the other six land use types were not obviously different, except for unused land. There were similar regularities in the relationship between landscape pattern and environmental factors for 2003 and 2010. The main factors with major impact on landscape were sunshine hours, slope gradient and altitude. Water surface and build-up land were in areas with higher sunshine hours, lower altitudes and gentler slopes. However, unused land and grassland were mainly in the other areas. Through land use/landscape pattern and environmental factor relationship, this paper determined land use/landscape pattern distribution characteristics in Qixia City. This study therefore provided theoretical basis for adjustments in agricultural land structure and in the general land use structure for optimized land use in the study area and beyond.
Editor-in-chief：LIU Changming
Competent Authorities：Chinese Academy of Sciences
Sponsored by：Institute of Genetics and Developmental Biology, Chinese Academy of Sciences; China Ecological Economics Society
Organizer：Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
ISSN 2096-6237
CN 13-1432/S
- Chinese core periodicals
- Core Chinese Sci-Tech Periodicals
- China's Top Science and Technology Periodicals
- Covered by Chinese Science Citation Database (CSCD)
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