Effects of different levels of NO donor (sodium nitroprusside, SNP) pretreatments and PEG-6000 treatment on the leaf relative water content, chlorophyll content, net photosynthesis rate, lipid peroxidation and cell protective enzyme activity in Elaeagnus mollis seedling leaves under water stress were studied. The results showed that exogenous NO had a remarkable positive effect on leaf relative water content and could increase chlorophyll content. Lower concentrations of NO (0.1, 0.2, 0.4 and 0.6 mmol · L-1SNP) could increase photosynthesis rate, but hihger concentrations of NO (0.8 and 1.0 mmol · L-1 SNP)had adverse effects. Exogenous NO could decrease MDA content and relative leakage ratio. With the increase of SNP level, POD activity in leaves showed an increasing trend, while CAT activity first increased and then decreased, and higher than CAT activity of the control. It is obvious that exogenous NO could retard the accumulation of active oxygen through inducing POD and CAT activities of leaves, alleviate the hurt of water stress to E. mollis seedlings, and increase its drought-resistant capacity.%研究了NO供体硝普钠(Sodium nitroprusside,SNP)预处理和PEG-6000渗透液处理对水分胁迫下翅果油树幼苗叶片相对含水量、叶绿素含量、净光合速率、膜脂过氧化和保护酶活性的影响.结果表明:外源NO能提高翅果油树幼苗叶片的相对含水量,缓解水分胁迫下叶片的水分丢失,提高其叶绿素含量;低浓度外源NO(0.1、0.2、0.4、0.6 mmol·L-1SNP)能促进叶片的光合速率,高浓度(0.8、1.0 mmol·L-1SNP)则明显抑制光合速率.外源NO使各处理组叶片丙二醛含量和相对电导率均降低;随着SNP浓度的升高,各处理组POD活性呈逐渐上升趋势,而CAT活性先上升后下降,且均高于对照.外源NO可通过诱导叶片POD和CAT活性的升高来延缓活性氧的积累,从而减轻水分胁迫对翅果油树的伤害,增强树木的耐旱能力.
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