中国生态农业学报(中英文)

Advances in the study of endophytes effects on soil microflora

WU Jiarui, WANG Hongwei, XIE Xingguang, DAI Chuanchao

2014, 22(11): 1259-1266. doi: 10.13930/j.cnki.cjea.140737

Abstract(1429) PDF(2037)

Abstract:
Soil microflora is an important part of soil ecological environment. The stability of soil microflora plays an important role in plant growth. Except for the plant growth promoting ability, some endophytes also significantly impact soil microflora. In this review, quantities of studies are summarized and effects of endophytes on soil microflora and the regulatory mechanisms are also discussed. Endophytes not only improve soil microbial composition and biomass, but also enhance soil enzyme activities and the expression of related enzyme genes. The mechanisms of these effects mediated by endophytes are complex. Living in soil, endophytes occupy the same niches and struggle for the sources of carbon and nitrogen with soil microbes. Meantime, endophytes provide plenty of carbon and nitrogen sources for soil microbes by degrading litters in the soil. They also produce some antimicrobial active substances and organic acids to affect soil microbes. In addition, endophytes regulate soil microorganisms by promoting the release and degradation of complex organic compounds, such as ligin and phenolic allelochemicals. Furthermore, endophytes reduce the toxicity of heavy metal in soil. In addition, the application of endophytes is discussed. The deficiencies in the existing researches are pointed out and the further researches are also put forward.

Effects of long-term fertilization on soil fungi

WANG Yi, LI Ji, CAO Zhiping, YANG Hefa

2014, 22(11): 1267-1273. doi: 10.13930/j.cnki.cjea.140315

Abstract(1376) PDF(1569)

Abstract:
Fungi are critical for the decomposition of terrestrial organic matter and subsequent global carbon cycle. High microbial diversity is essential for efficient nutrient recycling in soils. To investigate the impacts of different application modes of fertilizers on fungal communities, a long-term fertilization experiment (of over 20 years of continuous fertilizer treatments) was conducted in North China. Soil samples were collected from 4 treatments: effective microorganisms compost (EM), traditional compost (OF), chemical fertilizer (CF) and unfertilized control (CK) from March to October in 2012. The T-RFLP analysis, which is a polymerase chain reaction (PCR)-fingerprinting method commonly used for comparative microbial community analysis, was used to analyze the soil samples. Because of differences in T-RFLP patterns, a series of analyses - diversity index analysis, principal component analysis (PCA) and redundancy analysis (RDA) - was used to further determine soil fungal diversity in different treatments. Several multi-variate statistical approaches were used to interpret and compare the changes in T-RFLP fingerprints derived from different communities. Then the principal component analysis (PCA) and redundancy analysis (RDA) were particularly used in determining the trends in T-RFLP data. The results showed that fungal community structures in EM and OF were different from those in CK and CF. The ranges of Shannon-Weiner diversity index and the Simpson index in the samples were 2.64-3.53 and 0.03-0.08, respectively, under fertilzation treatments. While the highest Shannon-Weiner diversity index was in October and at the 0-20 cm soil layer under OF and EM treatments, the lowest was in March and at the 0-20 cm soil layer under CK treatment. Also while the highest Simpson index was in March and at the 0-20 cm soil layer under CK treatment, the lowest was in October and at the 0-20 cm soil layer under OF and EM treatments. Based on the comprehensive evaluation indexes of fungal community using PCA of T-RFs peak area and Shannon-Weiner index, fungal community was higher in EM and OF than in CF and CK treatments. The high fungal diversities in EM and OF treatments occurred in March, June and October. PCA analysis indicated that soil fungi under EM, OF, CF and CK treatments formed independent community structures. The communities were adaptable to own specific soil environments to form the dominant population. Redundancy analysis showed that fungal community composition was significantly influenced by soil pH, organic matter, total nitrogen, available phosphorus and available potassium. The above findings contributed significantly to the understanding of the specific changes in soil fungal diversity and fungal community in response to different fertilization treatments. The addition of different organic fertilizers improved a range of soil properties related with microbial activities after 19 years of treatment. Also fungi community became more diverse after application of organic fertilizer. It was concluded that organic fertilizer application was best strategy for increasing diversity of soil fungi.

Effects of nitrogen fertilizer application and rhizobial inoculation on yield and water use efficiency of pea/maize intercropping system

WU Kesheng, SONG Shangyou, LI Long, SUN Jianhao, ZHAO Jianhua

2014, 22(11): 1274-1280. doi: 10.13930/j.cnki.cjea.140805

Abstract(1422) PDF(1369)

Abstract:
Pea/maize intercropping has been a vital crop production mode in irrigated areas of Hexi Corridor in Gansu Province. However, there some problems of heavy fertilization and symbiotic N₂ fixation neglect have persisted in local crop production in the region. Thus field trials were conducted in Wuwei City of Gansu Province in 2011 and 2012 to study the effects of nitrogen fertilization and rhizobial inoculation on crop yield and water use efficiency of pea/maize intercropping system. The work aimed to determine an optimal nitrogen fertilizer application and rhizobial inoculation so as to save fertilizer and increase yield of pea/maize intercropping system. The results showed that while nitrogen fertilization had not significant effects on pea yield, yields of monocropped and intercropped pea increased on average by 12.7% and 4.8%, respectively, after inoculation. Yield of intercropped pea increased by 61.1% on average compared to that of monocropped pea. Yield of monocropped pea was highest (2 735 kg·hm^-2) under nitrogen fertilizer rate of 75 kg·hm^-2 with inoculation. Under nitrogen fertilizer rate of 75 kg·hm^-2, pea yield increased by 22.8% on average after inoculation. The effect of nitrogen fertilization on maize yield was significant. Yield of monocropped maize under nitrogen fertilizer rate of 300 kg·hm^-2 was 14 394 kg·hm^-2 and yield of intercropped increased by 61.8% compared with that of monocropped maize. Yield of maize intercropped with rhizobium-inoculated pea belt increased by 3.3% on average, compared with that intercropped with non-inoculated pea belt. Land equivalent ratio was larger than 1 under different treatments. The water use efficiency of pea reduced with increasing nitrogen fertilizer application, with the maximum value (12.9 kg·mm^-1·hm^-2) appearing under zero-N fertilizer use. Water use efficiency of maize first increased and then latter decreased under increasing nitrogen fertilization rate, with the maximum value (25 kg·mm^-1·hm^-2) appearing under nitrogen fertilizer dose of 300 kg·hm^-2. From the above results, it was recommended that the rate of nitrogen fertilizer application in maize for high grain yield and high water use efficiency was 300 kg·hm^-2 in pea/maize intercropping system. Then the recommended rate of nitrogen fertilizer application in pea for high grain yield and high water use efficiency was 75 kg·hm^-2 in pea/maize intercropping system. In filed production, pea yield significantly increased by the inoculation of rhizobia.

Effect of fertigation on apple production in different ecological-regions orchards

LU Yongli, BAI Fenghua, YANG Xianlong, LI Ru, GAO Yimin, TONG Yan'an

2014, 22(11): 1281-1288. doi: 10.13930/j.cnki.cjea.140293

Abstract(1398) PDF(1229)

Abstract:
In order to explore the effects of fertigation on 'Fuji' apple production in different ecological regions of Shaanxi Province, two field experiments (each with three treatments) were conducted simultaneously in Weibei Dry-land and Guanzhong Plain. The treatments consisted of conventional fertilization treatment [NPK(C)] and fertigation treatment [NPK(F)] using the same fertilizer rates as the conventional treatment, and half-dose fertigation treatment [1/2NPK(F)] using 50% of fertilizer rates of the conventional treatment. The yield, fruit quality, fruit nutrient uptake, fertilizer utilization and economic benefits of apple were then determined and evaluated. The results showed that due to the differences in ecological conditions, soil types and fertility levels of orchards in different ecological regions, the fertigation effects on apple production were obviously distinct. In contrast with NPK(C) treatment, NPK(F) treatment increased apple yield by 13.0%, fruit firmness by 10.6%, sugar acid ratio by 19.1%, and apple fruit uptake of N, P and K nutrients respectively by 36.0%, 75.3% and 44.8% in apple orchards in Weibei dry-land. In addition, partial factor productivity (PFP) increased from 18.2 kg·kg^-1 to 36.3 kg·kg^-1 under NPK(F). However, no significant increases were noted in apple yield, fruit quality and fruit nutrient uptake under 1/2NPK(F) treatment in Weibei Dry-land. In orchards in Guanzhong Plain, apple yield under 1/2NPK(F) treatment increased by 26.2% and apple fruit uptake of N, P and K nutrients increased respectively by 41.8%, 98.9% and 58.9%, compared those under NPK(C) treatment. Meanwhile, PFP increased from 27.2 kg·kg^-1 to 68.7 kg·kg^-1. However, the increment in apple yield under NPK(F) treatment was merely 14.1%, the changes in fruit nutrients uptake were insignificant. As for the economic benefits, in comparison with NPK(C) treatment, NPK(F) treatment enhanced economic benefits by 15 500 Yuan·hm^-2 for orchards in Weibei Dry-land and 36 500 Yuan·hm^-2 for orchards in Guanzhong Plain. Economic benefits under 1/2NPK(F) treatment were increased by 2 100 Yuan·hm^-2 for orchards in Weibei Dry-land and 72 800 Yuan·hm^-2 for orchards in Guanzhong Plain, compared with those under NPK(C) treatment. In conclusion, fertigation management significantly increased yield and fruit quality of apple orchards in different ecological regions in Shaanxi Province. However, the effectiveness of fertigation management differed apparently due to differences in ecological conditions in different regions. Therefore, the use of optimal fertilizer application rates in fertigation management was strongly recommended. The specific conditions of orchards formed the basis of optimal fertilizer application rates for high yields, fruit qualities, fertilizer use efficiencies and economic benefits.

Effects of inter-planting forage with tea on yield and soil fertility

HUANG Dongfeng, WANG Limin, LI Weihua, QIU Xiaoxuan, LUO Tao, WENG Boqi

2014, 22(11): 1289-1293. doi: 10.13930/j.cnki.cjea.140538

Abstract(1250) PDF(1148)

Abstract:
Studies on low-layer forage inter-planting with tea plants in China have been relatively late and considered less significant in classical research. Low-layer inter-planting models of forages in tea gardens are needed for in-deep understanding of economically viable forage-tea production. Comparison of none-forage interplant model in a field trial with three types of forages (bahiasgrass, white clover and amarillo) inter-planting in tea gardens for 3 years was carried out to determine the effects of tea yield and basic soil fertility. The results of the study showed that the three types of interplant models increased tea yield by 6.48%-20.26% and harvested fresh forage by 1 352-4 023 kg·hm^-2·a^-1. Compared with the first year of the experiment, the decreasing ranges of loss thickness of surface soil in tea gardens over the three years of experiment were respectively 25.0%-30.6%, 33.3%-38.9% and 53.3%-60.0%. Furthermore, basic soil fertility improved by three years of forage inter-planting. For example, soil fertility indexes of pH, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen and available phosphorus increased respectively by 9.64%-11.76%, 8.23%-76.13%, 13.59%-245.63%, 3.41%-210.51%, 1.37%-9.65%, 69.63%-109.33% and 11.40%-34.20%. The results of the study also showed that inter-planting white clover or amarillo in tea gardens were better than inter-planting bahiasgrass in terms of increased tea yield or improved basic soil fertility. The two types of forages were worthy of widespread inter-planting modes in tea gardens in the study area and beyond.

Effects of different governance patterns of small watershed on fractal features of soil micro-aggregates in the hilly areas of central Sichuan Basin

YAN Jianmei, HE Lianjun, HE Binghui, TIAN Taiqiang

2014, 22(11): 1294-1300. doi: 10.13930/j.cnki.cjea.140556

Abstract(1096) PDF(1175)

Abstract:
The exploration of the fractal features of soil micro-aggregates under different governance patterns of small watershed can provide scientific basis for vegetation restoration and for soil and water loss control in the hilly areas of Sichuan Hilly Basin. Thus this paper analyzed the composition and fractal features of soil micro-aggregates and its relationship with soil physicochemical properties. The results showed that soil micro-aggregates of 0.01-0.05 mm size were dominant aggregates in 0-10 cm soil layer (28.63%) and 10-20 cm soil layer (28.04%). This was followed by soil micro-aggregates of 0.001-0.005 mm size for 0-10 cm soil layer (25.90%) and 10?20 cm soil layer (26.33%). Significant differences were observed among different patterns of governance. The range of fractal features of soil micro-aggregates was 2.643-2.717. The sequence of fractal features of soil micro-aggregates for different governance patterns was conservation forest < orange forest < walnut forest < bare-land < slope-terrace < grading of slope land. Linear relation between fractal features and composition of soil micro-aggregates was observed. Fractal features of soil micro-aggregates showed significant positive correlations with available K and total K. However, negative correlations were noted between fractal features of soil micro-aggregates and total soil porosity, alkali-hydrolyzable N, total N and organic matter. The fractal features of soil micro-aggregates better reflected the physicochemical properties of soils in the hilly areas of central Sichuan Basin. Woodland was the best mode for vegetation restoration and controlling soil and water loss in the basin.

Research on soil water dynamics of farmland in Mu Us Sand Land

BAO Han, HOU Lizhu, SHEN Jiangen, ZHENG Han, ZHANG Xin

2014, 22(11): 1301-1309. doi: 10.13930/j.cnki.cjea.140222

Abstract(1233) PDF(1397)

Abstract:
Soil water is a key parameter in the interactions among the earth, atmosphere and hydrological cycle. Understanding soil water dynamics is critical in studying biophysical processes of the land surface. The Mu Us Sandy Land (MUSL) in northwest China is a dominant semi-arid climate region with scarce precipitation and surface water resources and groundwater as the main sources of water. Thus as water is the main factor restricting the development of the agriculture in MUSL region, it is vital to study soil water dynamics in farmlands to guide local agricultural production. Previous studies on soil water dynamics in MUSL and shrub areas of the region failed to take into account soil water dynamics during spring maize growing season, which is the main cultivation period in MUSL region. Therefore in this study, mainly based on field experiments, we examined soil water dynamics during spring maize season in MUSL by analyzing observed data for groundwater, soil water content, soil water potential, irrigation, rainfall, evaporation and maize transpiration. The results showed that groundwater clearly hydraulically correlated with soil water. Also significant correlations were observed between groundwater and soil water content at different depths, especially at 40-60 cm depth with a correlation coefficient >0.8. Besides, groundwater drawdown lowered soil water stable layer position and weakened hydraulic connections among layers, which limited soil water preservation. Meanwhile increasing maize water demand and declining groundwater table increased vertical variation in soil water content. Based on the field data for soil water content and soil water potential, we noted that the soil water dynamics tracked a curve of weak, strong and weak again during the period from seedling stage to dough stage. Also while about 20 cm soil depth was the main maize water absorption layer, the soil layer of 30-40 cm depth was relatively dry. Irrigation was applied only under water stress. Our study showed that it was possible to determine whether irrigation was needed or not during maize growth by analyzing soil water contents at the 30 cm and 40 cm soil depths. When soil water potential at the 10 cm depth dropped to ?0.18 bar, crop physiological processes induced hydraulic lift by maize root. By characterizing soil water dynamics during spring maize season in MUSL farmlands, our study provided essential reference database for agricultural water use along needed theoretical basis for water management in MUSL region.

Comprehensive evaluation of soil erosion durability of bio-banks on slope lands in purple hilly areas

WU Lili, ZHANG Renzhi, KANG Lijun

2014, 22(11): 1310-1317. doi: 10.13930/j.cnki.cjea.140343

Abstract(1536) PDF(1204)

Abstract:
Using bio-banks on sloppy farmlands in purple hilly areas as the study objects, this paper conducted a comprehensive evaluation of the durability of soil erosion of different kinds of bio-banks. The paper used data from field surveys and indoor analyses to explore the anti erodibility of four types of bio-banks of mulberry, Chinese prickly ash, alfalfa and natural grass on sloppy farmlands in purple hilly areas. The result showed that: 1) bio-banks effectively increased soil moisture and organic matter content, and better improved soil structure. The bio-banks with woody plants showed more obvious effects than those with herbaceous plants. 2) Among the four indicator categories of evaluation of soil erosion durability, water stable aggregate indicators had the highest variability - with range of 46.84%-22.81% and average of 31.10%, followed by micro-aggregate indicators - with range of 41.08%-20.55% and average 30.97%, and then organic matter content - with average of 17.11%; 3) Principal component analysis suggested that the 13 indicators characterizing the durability of soil erosion in the study area were optimized into four indicators - >0.5 mm water stable aggregate content, aggregate dispersion rate, water stable index and <0.001 clay particle content; 4) The comprehensive index of the durability of soil erosion of four bio-banks on sloppy farmland was ranked as follows - Chinese prickly ash bio-bank > mulberry bio-bank > alfalfa bio-band > natural grass bio-bank. And their erosion durability was ranked as: Chinese prickly ash bio-bank > mulberry bio-bank > alfalfa bio-bank > natural grass bio-bank. The results laid the basis for improving the evaluation indicator system of the durability of soil erosion at local, regional and global scales, and choice of water and soil conservation measures.

Contributions of aboveground litter to soil respiration in coniferous and deciduous plantations

ZHAO Xin, ZHANG Wanjun, SHEN Huitao, AI Zhipin, LIAN Shiqi, LIU Changbai

2014, 22(11): 1318-1325. doi: 10.13930/j.cnki.cjea.140458

Abstract(1259) PDF(1359)

Abstract:
Aboveground litter is of great importance in the study of carbon cycle in terrestrial ecosystem. However, current understandings of the contribution of aboveground litter to soil respiration are far too limited. In order to investigate the degree of contribution of aboveground litter to soil respiration, three treatments of non-litter (NL), cover litter (CL) and the control (C, natural litter cover) were set up in ten-year old Pinus tabulaeform and Populus plantations in Beijing-Tianjin sandstorm source area. Each treatment was replicated three times in galvanized sheet irons of size of 40 cm × 40 cm × 9 cm, 4 cm of which was above ground surface. Polyvinyl chloride (PVC) collars (with 10 cm inside diameter) were installed in each plot for soil respiration measurements. The field experiments were conducted from March 2013 to November 2013 and measurements taken only on days without precipitation and/or high winds to minimize equipment damage and measurement error. Soil respiration rates (R_s) were measured approximately once a month during the period of the experiment using Li-6400 portable CO₂ infrared gas analyzer (IRGA) equipped with Li-6400-09 chamber (Li-COR IC., LiColn, NE, USA). R_s was continuously measured in three cycles at each collar and the three measurements averaged for the collar mean. Soil temperature was monitored simultaneously along soil respiration using a thermocouple penetration probe inserted in the soil to the depth of 5 cm in the vicinity of the respiration chamber. Soil moisture in the top soil layer (0-5 cm) was monitored using the oven-dry method. Results showed that soil respiration was significantly different among different treatments (P < 0.05). The mean soil respiration rates (R_s, μmol·m^-2·s^-1) under P. tabulaeform and Populus plantations in the NL, CL, C treatments were respectively 2.28, 2.81, 2.55, and 2.13, 2.62, 2.32., indicating that CL > C > NL. Soil respiration was positively correlated with soil temperature at 5 cm soil depth (R² = 0.54 to 0.88, P < 0.05), but not with soil moisture at 5 cm soil depth. The order of sensitivity to temperature of soil respiration (Q₁₀) was NL < CL < C. The contribution rates of aboveground litter to soil respiration under P. tabulaeform and Populus plantations were 20.78% and 20.75%, respectively, suggesting little difference in litter contribution to soil respiration between P. tabulaeform and Populus. The results of the study could have significant implications for future study on soil respiration and the estimation of carbon sequestration of young coniferous and deciduous plantations in the Beijing-Tianjin sandstorm source area.

Effect of low temperature stress on physiological characteristics of flag leaf and its relationship with grain yield during panicle primordium differentiation stage of early rice

SUN Qing, YANG Zaiqiang, GAO Lina, YIN Jianmin, WANG Xuelin, LI Lingli

2014, 22(11): 1326-1333. doi: 10.13930/j.cnki.cjea.140520

Abstract(1470) PDF(1538)

Abstract:
The effects of low temperature stress on physiology and yield characteristics of early rice in Jiangxi Province as driven by artificial environmental controls were studied in this paper. The paper also analyzed the relationship of physiological characteristics and yield components with yield of early rice under low temperature (22 ℃/17 ℃) in the study area with gray correlation analysis. The normal daytime temperature in the region was 30 ℃ and that of night time was 25 ℃. With prolonged low temperature treatment, chlorophyll a, chlorophyll b and carotenoids contents of early rice leaves rose initially and dropped later. Maximum photosynthetic rate, light saturation point and initial light use efficiency tracked a downward trend according to photosynthetic light response curves. Light compensation point was apparently on the rise. Fluorescence parameters of qP, ETR, F_v/F_m had an early-increasing/later-decreasing tendency. Conversely, qN reached its maximum value after low temperature stress for 6 d. While activities of SOD, POD and contents of MDA and soluble protein had an early rise and later drop, CAT activity followed a declining trend. Yield, spike length, seed setting rate, spike rate, grain weight and other yield traits followed a decreasing tendency. Based on gray correlation analysis, in relation to yield, the rank of correlation degree was as follows: grains per panicle > spike length > secondary branch number > primary branch number > 1000-kernel weight > CAT, and the correlation degrees of these traits were all greater than 1. The physiological traits, such as initial light use efficiency, light saturation point, ETR, F_v/F_m, chlorophyll a/chlorophyll b also had greater correlation with early rice under low temperature. These physiological traits could be used as indicators to evaluate early rice yield under low temperature stress.

Effects of sucrose on rice root adaptability and phosphate transporter gene expression under phosphorus stress

SU Jun, ZHANG Wujun, DU Lin, SONG Yana, FU Yanping

2014, 22(11): 1334-1340. doi: 10.13930/j.cnki.cjea.131137

Abstract(1758) PDF(1150)

Abstract:
Phosphate is one of the most important essential elements for plant growth and development. Although soils are normally rich in phosphorus, most phosphorus compounds exist as either insoluble inorganic phosphate (Pi) or organic phosphate and rice Pi availability is extremely low particularly in acidic paddy fields. Breeding low phosphorus tolerance plants has been the most fundamental method for meeting phosphours deficiency and improving fertilizer use efficiency. It is important to highlight the adaptation mechanism of plants to low soil phosphorus availability. Thus the aim of this work was to understand the role of sucrose in regulating rice seedling response to phosphorus stress. Rice (Oryza sativa L.) cultivar ('Minhui86') was grown for 35 days under normal phosphate (85 mg·L ^-1 KH₂PO₄) without sucrose (PS-), normal phosphate with 3% sucrose (PS+), no phosphate without sucrose (P-S-) and no phosphate with 3% sucrose (P-S+). The morphological and physiological responses of rice to phosphorus deficiency and the expression of acid phosphatase 1 gene (OsSAP1) and 11 of phosphate transporter genes (OsPTs) under low phosphorus stress were analyzed. The results showed that rice seedling root growth in sucrose conditions had striking changes in morphology and architecture under low phosphorus stress. The root changes included increases in both total and lateral root numbers, length of root and root/shoot ratio. Analysis of acid phosphatase activity indicated that root-secreted acid phosphatase was depressed under PS condition, while activity of acid phosphatase in plant cell improved. Among 11 high affinities phosphate transporter genes (OsPTs), 4 of them, OsPT2, OsPT3, OsPT4, OsPT6, were expressed predominantly in root and displayed sensitivity to exogenous sucrose under low phosphorus stress. This suggested that sucrose likely played a role in maintaining phosphorus absorption and homeostasis by regulating phosphate transporter.

ABA modulates root growth through regulating auxin in Arabidopsis thaliana

YUAN Bingjian, ZHANG Senlei, CAO Mengmeng, WANG Zhijuan, LI Xia

2014, 22(11): 1341-1347. doi: 10.13930/j.cnki.cjea.140240

Abstract(1471) PDF(2162)

Abstract:
As sessile organism, plants exhibit an amazing developmental plasticity in adapting to changing growth conditions in response to environmental stimuli. As an important organ of plants, roots variously make active changes in the face of different stimuli. It is well known that ABA (abscisic acid) is an important molecule that inhibits root growth. ABA receptor PYR1/PYL mediates ABA signaling transduction by binding with PP2C proteins and activating kinases SnRK2s. However, little is known about how ABA regulates root growth and plastic development. In order to understand the mechanism underlying root growth inhibition by ABA, the effects of ABA on the size and activity of root meristem, meristematic cell cycle, and auxin amount and distribution patterns were analyzed with Arabidopsis thaliana as materials. The results showed that ABA inhibited the growth of primary roots and reduced the size of meristems of primary roots. The inhibition effect of ABA on pyr1/pyl1/pyl2 root growth reduced, which showed that ABA receptor PYR1/PYL was involved in the inhibition of root growth. Further analysis showed that ABA treatment blocked G2/M-phase transition during cell division with the accumulation of cyclin proteinCYCB1;1::GUS expression. In addition, we noted that the amounts and distribution patterns of auxin in the roots changed with treatment of ABA. The results suggested that ABA inhibited the growth of roots by modulating synthesis and auxin response which in turn influenced cell division in root meristem.

Relationships among weed suppression effect, allelopathy and agronomic characteristics of Oryza longistaminata and related descendants

XU Gaofeng, SHEN Shicai, ZHANG Fudou, ZHANG Yuhua

2014, 22(11): 1348-1356. doi: 10.13930/j.cnki.cjea.140535

Abstract(1321) PDF(1239)

Abstract:
Rice allelopathy has been a new environmentally-safe way in paddy weed management that has met the needs of sustainable agriculture. This study explored the linkages among field weed suppression effects, allelopathy and agronomic characteristics of Oryza longistaminata and its related descendants. It critically exploited and utilized the important aspect of allelopathic genes of wild resources of rice germplasm. In the paper, wild rice (O. longistaminata) with allelopathic potential and 'RD23' (O. sativa cultivar) without allelopathic potential and their F1 (RD23 × O. longistaminata) and F2 descendants were used in indoor assay and pot cultivation experiment in greenhouse to determine the effect of allelopathy and agronomic characters on weed suppression effects to barnyard grass. The results showed that weed suppression effects of strong allelopathic potential rice were significantly higher than those of rice with weak allelopathic and non-allelopathic potential at a rhizosphere distance of 0?3 cm under pot culture conditions. However, strong allelopathic potential rice not always had higher weed inhibition effects with increasing rhizosphere distance. When rhizosphere distance was greater than 3 cm, rice with strong tillering ability, fast growth and long upright stems had stronger weed inhibition effects under pot culture conditions irrespective of the allelopathic potential of the tested rice materials. Density control effect of rice seedlings aged 60 days was lower than those aged 30 days at rhizosphere distance of 0?3 cm. However, biomass control effect and plant height inhibition rate were greater for seedlings aged 60 days. With increase of rhizosphere distance, not significant difference was noted between seedling with two ages, except density control effect at rhizoshpere distance of 3?6 cm. Correlation analysis of allelopathy synthesis effects with density control effect, biomass control effect and plant height inhibition rate depicted weakening correlation with increasing rhizosphere distance of the tested rice materials, but with significant correlation at 0?3 cm rhizosphere distance. Although no correlation was noted between plant height, tiller number and density control effect, but biomass control effect and plant height inhibition rate was positively correlated with plant height and tiller number of the tested rice materials. The study suggested that field weed suppression effect of O. longistaminata and its F1 (RD23 × O. longistaminata) and F2 accessions depended on allelopathy, seedling age, plant height, tiller number and other factors of the rice field. Allelopathy was an important factor at 0-3 cm rhizosphere distance and 30 days of rice seeding age.

Physiological response of Alopecurus aequalis leaf to water extracts from allelopathic wheat (Triticum aestivum L.) root tissues

QIU Qiujin, LI Yuanping, WANG Wei, CHEN Shan, XIAO Qingtie, ZHENG Xinyu, WANG Jingyuan, LIN Ruiyu, LIN Wenxiong

2014, 22(11): 1357-1363. doi: 10.13930/j.cnki.cjea.140470

Abstract(1590) PDF(1195)

Abstract:
In order to illustrate the physiological mechanism of weed suppression ability of allelopathic wheat (Triticum aestivum L.), two strong allelopathic wheat accessions ('115/Qinghai' and '92L89') and one weak allelopathic accession ('Kang10103') were used in hydroponic culture experiments. Alopecurus aequalis seedlings were cultured in the hydroponic culture solutions with 0.2%, 0.5% and 1.0% of roots water extracts of the above three wheat accessions. The fresh weights, contents of chlorophyll (SPAD value), soluble proteins, methane dicarboxylic aldehyde (MDA), flavonoids, total phenols and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of A. aequalis seedlings were determined after cultured for 21 days. The results showed significant differences in weed suppression ability among wheat accessions and concentrations of roots water extracts. Strong allelopathic wheat accessions had higher inhibitory rates to A. aequalis seedlings than weak allelopathic wheat accessions. The inhibitory rate to A. aequalis seedling fresh weight of different wheat root water extracts within designed concentrations was in the order of '115/Qinghai' (24.7%-74.3%) > '92L89' (15.7%-71.6%) > 'Kang10103' (13.8%-61.4%). Wheat accessions with extract concentrations of 0.2%, 1.0% and 5.0% had inhibitory rates of 13.8%-24.7%, 41.7%-66.4% and 61.4%-74.2%, respectively. The contents of chlorophyll decreased with increasing extract concentration while the contents of soluble protein, MDA, flavonoids, and activities of SOD, POD and CAT increased with decreasing extract concentration. Strong allelopathic wheat accessions had higher stimulation effects on physiological indexes than weak wheat accessions. In addition, total phenol content of A. aequalis seedling treated with 1.0% water extract of '115/Qinghai' wheat and 5.0% water extracts of the three wheat accessions were higher than the control. Thus allelopathy effects of wheat root water extracts enhanced enzyme activities, stimulated metabolism of anti-oxidatives, accompanied stronger lipid peroxidation, degraded leaf chlorophyll and inhibited growth of A. aequalis seedling.

Allelopathic effects of fresh parsley root acetone extracts on Fusarium oxysporum f. sp. cucumberinum and allelochemicals identification

GAO Xiaomin, WANG Jugang, LI Jie, MA Liguo, HAO Jing, YUN Xingfu

2014, 22(11): 1364-1371. doi: 10.13930/j.cnki.cjea.140582

Abstract(1225) PDF(1466)

Abstract:
In field production of cucumber (Cucumis sativus), it is relatively difficult to control wilt caused by Fusarium oxysporum. However, the extent of infection is reduced by crop rotation with parsley (Apium graveloens). To identify inhibitory allelochemicals released into the soil by parsley crop, acetone extracts from fresh parsley roots were examined after a repeated series of purification (four cycles) in column chromatography (10 mm × 300 mm) using a column with silicone coating. We used a bioassay that incorporated the various column fractions into PDA medium and co-cultured the plates with F. oxysporum f. sp. cucumberinum. By measuring colony diameter and spore germination rate, we screened the best fractions in terms of allelopathic inhibition effect and identified further allelochemicals of the fourth chromatography using GC-MS. Optimal fractions (RA3246, RA3344, RA9889 and RA91064) obtained from the fourth cycle of chromatography showed considerable allelopathic effect. The allelopathic inhibition effects of the four optimal fractions on hypha growth compared with the fourth cycle tomographic acetone (the control, ACK4) respectively were 28.69%, 37.83%, 42.44% and 33.83%, while spore germination inhibition rate were respectively 50.72%, 50.66%, 55.02% and 59.37%. Further identified were organic acids, phenols, alcohols, esters, heterocyclic organic matter, 6 forms of N compounds and 12 forms of allelochemicals in the GC-MS analysis. These included 3-Hydroxymandelic acid, thioglycolic acid, 2,4-Di-tert-butylphenoc, 2-Dodecanol, 2-Propenoicacid, 2-methyl-, tridecylester, 2-dimethylcyclohexylamine ester, dodecyl acrylate, 2-Propenoic acid, 2-methyl-pentadecyl ester, 3,4-epoxytetrahydrofuran, hexadecyldimethylamine, (Z)-octadec-9-enamide and dibutylcyanamide. The results provided the needed theoretical basis for the prevention and control of Fusarium wilt of cucumber by using extracts of parsley.

Evaluation and changing characteristics of fertilizer input in different agricultural systems in the Three Gorges Reservoir Area

ZHONG Jianbing, SHAO Jing'an, XIE Deti, NI Jiupai

2014, 22(11): 1372-1378. doi: 10.13930/j.cnki.cjea.140340

Abstract(1211) PDF(929)

Abstract:
As environmental issues have become increasingly prominent in rural development, researches on investment in different agricultural systems and the transformation processes of agricultural products are critical in resolving non-point source pollution issues of rural environment. They also contribute to the development of targeted programs for controlling non-point source pollution. In this paper, the PRA (Participatory Rural Appraisal) method was used to assess fertilizer input of different modes of management of agriculture in the Three Gorges Reservoir Area of Chongqing. Based on the investigated materials and the results of comprehensive assessment of the research area, agricultural production and operation modes were divided into general farmers (GF), big farming households (BF), company enterprises (CE), big breeding households (BB), big farming and breeding households (FB) and co-operative farmers (CF). By accounting for fertilizer input per unit land area in different agricultural operation modes, the distinct variation characteristics of the quantity and structure of fertilizers were identified in the research area. The results showed that: 1) The total amount of fertilizer consumption increased from 1997 to 2011, while the total amount of compound fertilizer grew significantly in recent years. 2) Although different agricultural operation modes had different structures of fertilizers, there were some internal similarities existed among GF, BB and FB and also among BF, CE and CP. While GF, BB and FB farmers used large proportions of conventional fertilizers, BF, CE and CP farmers used more emerging fertilizers like organic fertilizer, K fertilizers, etc. 3) The structures of fertilizer in the research area were dominated by conventional fertilizers, with significantly higher N and P input per unit land area under GF and BF than under CE, BB, FB and CP. 4) The variations in planting structures were due to variations in agricultural operation modes. GF, BB, and FB modes were mainly of traditional crops like corn, rice, sweet potato and irish potato, showing a small but comprehensive characteristics. While BF, CE and CP had the great breakthrough in terms of technological support, commercial production operations in some areas turned to the production of distinct crops. The order of fertilizer input per unit land area for different corps of the agricultural operating modes in the Three Gorges Reservoir Area of Chongqing was corn > vegetables > potatoes > other crops > sweet potatoes > fruit garden > paddy.

Spatialization and analysis of agricultural output value in Xinjiang

SHAO Shuangshuang, SHI Qingdong, LIU Man, TANG Cunshi

2014, 22(11): 1379-1384. doi: 10.13930/j.cnki.cjea.140611

Abstract(1283) PDF(1412)

Abstract:
Spatialization of agricultural output value is a form of spatial statistics critical for analyzing agricultural output value. As a key agricultural province in China, there is the necessity to analyze the factors affecting the spatial distribution characteristics and output value of agriculture in Xinjiang Uygur Autonomous Region. This is critical for adjusting agricultural structure towards high productivity. To analyze agricultural output value on geo-administrative distribution, this paper established a multi-variate regression model with county-based areas of land use types and river lengths as independent variables in combination with area weighted method to spatialize agricultural output value in Xinjiang at 1.0 km spatial resolution. The results of analysis of agricultural output value of Xinjiang in 2012 showed that (1) agricultural output value was closely related to areas of total cultivated land, forest land, grassland and length of local rivers. (2) The suitability of multi-variate regression simulation of agricultural output value was satisfactory with the linearity between the predicted and actual values up to 0.82. (3) The results of the spatial simulation suggested that the overall level of agricultural output value was low in Xinjiang, which was less than 5 000 Yuan per km². High value areas were concentrated in the Ili Region, Tuscaloosa Area, the north slope of Tianshan Mountain, and the upper and middle reaches of Tarim River. The areas with low values were mainly in the south of Taklimakan Desert. The whole distribution of agricultural output value was in zonal or sheet-like pattern. Most of the high value areas were belonged to the sheet-like pattern. The feature of zonal distribution was closely associated with local rivers and roads, but more especially with local river. Zonal distribution areas were mainly along the Tarim River Basin, Kongquehe River, Yeerqiang River Valley and Ili River Valley. The paper further analyzed the relationship between the main roads and agricultural output value. It was noted that the nearer to the roads, the higher were the agricultural output values. (4) The relationship between rivers and agricultural output values illustrated that water resources were the restricting factors of perfect agricultural development in arid areas. (5) The factors affecting the simulation accuracy included the inherent objective conditions of Xinjiang, human factors, regional differences and internal differences in production capacity of land use. Compared with previous studies, this paper considered on-the-ground conditions in arid areas and highlighted the importance of water resources in agricultural development and productivity. This had a real practical value for structural adjustment and optimization of agricultural industry in Xinjiang.

2014 Vol. 22, No. 11