干旱胁迫对不同生态型大豆生理生化特征的影响

为了研究干旱胁迫对大豆生理生化特征和产量的影响，选用22份不同生态型大豆品种为研究材料，用盆栽称重法与大田试验结合的方法，研究花期不同生态型大豆抗旱生理生化特征。结果表明：干旱胁迫下，不同生态型大豆品种的叶片相对含水量、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性、叶绿素a含量、总叶绿素含量和净光合速率都有一定程度的降低，与大豆品种的抗旱性均呈正相关，表现为抗旱性强的品种下降幅度较小，而抗旱性弱的品种下降幅度较大；而丙二醛含量、相对电导率和可溶性糖都有一定程度的增加，与抗旱性均呈极显著负相关，表现为抗旱性强的品种增加的幅度较小，而抗旱性弱的品种则相反；脯氨酸含量与抗旱性呈极显著正相关，表现为抗旱能力强的品种脯氨酸含量增加幅度大。这一结果说明，在干旱胁迫环境下，水分亏缺降低了大豆叶片相对含水量，膜脂过氧化伤害加重，引起丙二醛的累积，相对电导率升高，游离脯氨酸及可溶性糖含量升高，而丙二醛含量的升高导致保护酶活性降低，同时水分亏缺导致叶绿素含量降低，净光合速率下降，最终导致产量下降。

Influence of Drought Stress on Physiological and Biochemical Characteristics of Different Eco-types of Soybeans

In order to study influence of drought stress on physiological, biochemical and yield of soybean, 22 different eco-types soybean cuhivars were used as materials to test drought-resistant characteristics and physiological response in the conditions of pot experiments and field tests with normal water supply and water stress. The result showed that, among the 22 cultivars, ＇Jinda74＇ had the strongest drought resistance and ＇Bianjing＇ had the weakest drought resistance. Under water stress, relative water content, activity of POD and SOD, chlorophyll a content, total chlorophyll content and net photosynthetic rate declined. The cuhivars with strong drought resistance had a smaller decline ranges than the weak. The indexes were positively correlated with drought resistance, the correlation coefficient were respectively r=0.8455, r=0.9764, 1=0.8776, 1=0.9118,r=-0.8803, r=0.8312. MDA content, relative conductivity and soluble sugar content increased. The cultivars with strong drought resistance had smaller increasing rages while the cultivars with weak drought resistance had greater increasing rage. These indexes were negatively correlated with drought resistance, the correlation coefficient were respectively r=-0.7847, r=-0.8726, r=-0.7025. Under drought stress, Pro has a very significant positive correlation （1=0.8117） with drought resistance, it had a larger increase in stronger drought resistance varieties. The results indicated that water deficit caused RWC in soybean leaves reduced, lipid peroxidation damage increased, MDA accumulation, RC increased, Pro and SS increased. MDA content was responsible for declining activity of protecting enzymes. At the same time, water deficit resulted in declining content of chlorophyll, photosynthetic rate and biomass. The stronger drought-resistant cultivars not only have higher yield under normal water supply but also get a stable yield under drought stress.