高温胁迫对不同耐热型马铃薯块茎形成期生长和光合特性的影响

Growth and photosynthetic characteristics of different heat-sensitive potato genotypes during the tuberization stage under high-temperature stress

  • 摘要: 全球变暖对粮食生产的负面影响日益受到关注, 马铃薯是重要的粮菜兼用作物, 对高温敏感。探究耐热和热敏感型马铃薯资源在响应高温胁迫时的生理差异, 可为深入研究马铃薯耐热机制提供理论依据。本研究以耐热型品系‘滇187’(D187)和热敏感型品种‘青薯9号’(QS9)为材料, 在30 ℃高温胁迫处理2周后, 分析2个马铃薯材料在块茎形成期的植株形态和光合作用差异。在植株形态方面, 高温使马铃薯植株株高和节间长度显著(P<0.01)增加, 叶片直立, 叶片长度和面积缩小, 株型更为紧凑; 与QS9相比, D187叶片数和披垂角更为稳定。高温胁迫下马铃薯植株水分散失加快, 水分利用率降低, 对CO2吸收和低浓度CO2利用能力减弱, 呼吸作用消耗增加, 1,5-二磷酸核酮糖(RuBP)的再生能力减弱, 黑暗下的叶绿素荧光参数降低, 光下叶绿素荧光参数升高, 对有限强光的利用能力增强。高温胁迫下, D187叶片具有更高的净光合速率、水分利用效率、最大净光合速率、表观量子效率、羧化效率、最大羧化速率、最大电子传递速率, 更低的光补偿点和暗呼吸速率, 说明D187光合能力更强、弱光利用率更高、呼吸消耗更低、碳同化能力更强。D187的形态和光合作用指标中, 可塑性指数大于0.5的参数均多于QS9, 平均可塑性指数(0.448)高于QS9 (0.418), 说明耐热型马铃薯能够更好地通过调节植株形态和光合作用来适应高温环境。

     

    Abstract: The potato (Solanum tuberosum L.) is an important grain and vegetable crop. Global warming affects its growth and production owing to its high temperature sensitivity. Investigating the physiological differences between heat-tolerant and heat-sensitive resources can help rationalize the mechanism of high-temperature resistance in potatoes. The parameters related to the morphology and photosynthesis of the heat-tolerant line ‘Dian 187’ (D187) and the heat-sensitive cultivar ‘Qingshu 9’ (QS9) were measured and analyzed after two weeks of high-temperature stress at 30 ℃. Under high-temperature stress, the plant height and internode length were increased, the leaves were upright, the length and area of leaves were reduced, and the plant architecture was more compact. The extent of change in the leaf number and bend angle in D187 was greater than that in QS9. The high-temperature affected potato net photosynthetic rate, water use efficiency, maximum net photosynthetic rate, apparent quantum yield, carboxylation efficiency, maximum carboxylation rate, and maximum electron transport rate, which were lower in QS9 than those in D187 under high-temperature stress. Furthermore, D187 had a lower light compensation point and dark respiration rate than the heat-sensitive cultivar (QS9), and as a result of its strong adaptability, the number of indexes with phenotypic plasticity index exceeding 0.5 in D187 was more than that in QS9. The mean phenotypic plasticity index of morphology, photosynthesis, and yield was 0.448 in D187, which was higher than that in QS9 (0.418). Furthermore, under high-temperature stress, the ability to absorb CO2 and low-concentration CO2 utilization were weakened, along with the acceleration of water loss and the reduction of water use efficiency in potato plants. Consequently, respiratory consumption increased, and the regeneration abilities of ribulose 1,5-diphosphate (RuBP) and chlorophyll fluorescence parameters were reduced in the dark. In contrast, chlorophyll fluorescence parameters increased under light, and the utilization ability of limited light was also enhanced. Differences in morphology and photosynthetic self-adaptation abilities are the main reasons for the difference in high-temperature resistance between heat-tolerant and heat-sensitive resources, which will help clarify the mechanism of high-temperature adaptability in potato plants and provide references for the selection of cultivars with high-temperature resistance and innovation in cultivation techniques.

     

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