干旱胁迫下外源NO对核桃幼苗生理特性的影响

Effects of Exogenous Nitrogen on Physiological Characteristics of Walnut Seedlings under Drought Stress

本研究以两年生核桃幼苗为供试材料,探讨外源NO对干旱胁迫下核桃幼苗生理的影响,为外源NO对植物抗旱性的影响和及水分管理提供理论依据。本研究根据试验地当地降雨量,对核桃幼苗控制灌水量进行干旱胁迫,并在胁迫结束后喷施不同浓度的NO供体SNP(0.2mmol/L,0.5mmol/L,1.0mmol/L,1.5mmol/L,2.0 mmol/L)。喷施结束后测定核桃叶片净光合速率(Pn)、气孔导度(Gs)、叶绿素(Chl)、可溶性糖(SS)、脯氨酸(Pro)、丙二醛含量(MDA)、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT),并分析各指标与核桃幼苗抗旱性能力之间的关系。通过主成分分析法对各项生理指标进行分析,得出不同浓度SNP抗旱性的排序为1.5 mmol/L>1.0 mmol/L>2.0 mmol/L>0.5 mmol/L>0.2 mmol/L。结果表明,干旱胁迫后,一定浓度外源NO处理缓解干旱对核桃叶片光系统的伤害,促进干旱胁迫后核桃叶片可溶性糖和脯氨酸的积累,降低丙二醛含量,提高叶片保护酶(CAT, SOD, POD)活性。研究结果说明干旱胁迫下核桃幼苗对外源喷施NO的生理响应,为外源NO提高苗木抗旱性的研究提供参考依据。

In this research, two-year-old walnut seedlings were used as materials to investigate the effects of exogenous NO on the physiological characteristics of walnut seedlings under drought stress, which provided a theoretical basis for the effects of exogenous NO on plant drought resistance and water management. In this study,according to the local rainfall of the experimental site, the drought control of the walnut seedlings was controlled,and the NO donor SNPs(0.2 mmol/L, 0.5 mmol/L, 1.0 mmol/L, 1.5 mmol/L, 2.0 mmol/L) were sprayed with different concentrations after the stress. After the spraying, the net photosynthetic rate(Pn), stomatal conductance(Gs),chlorophyll(Chl), soluble sugar(SS), proline(Pro), malondialdehyde content(MDA), superoxide dismutase(SOD),peroxidase(POD), catalase(CAT) and analysis of the relationship between various indicators and the ability of walnut seedlings to drought resistance. Through the principal component analysis method, the physiological indexes were analyzed, and the order of drought resistance of different concentrations of SNPs was obtained as1.5 mmol/L>1.0 mmol/L>2.0 mmol/L>0.5 mmol/L>0.2 mmol/L. The results showed that after drought stress, a certain concentration of exogenous NO treatment alleviated the damage of drought on the light system of walnut leaves, promoted the accumulation of soluble sugar and proline in walnut leaves after drought stress, decreased the content of malondialdehyde and increased the protective enzymes of leaves(CAT, SOD, POD) activity. The research results showed that the physiological responses of walnut seedlings to NO by drought stress could provide a reference for the study of exogenous NO to improve the drought resistance of seedlings.