外源NO对Pb²⁺胁迫下桢楠生理特性的影响

Effect of Exogenous NO on Physiological Characteristics of Phoebe zhennan on Pb²⁺ Stress

摘要: 本试验探究了在Pb²⁺胁迫下，不同浓度的外源NO (nitric oxide)供体SNP (亚硝基铁氰化钠)溶液对桢楠(Phoebe zhennan)幼苗叶片生理特性的影响。结果表明，900 mg/L的Pb(NO₃)₂会使桢楠小苗叶片中MDA含量显著的升高(P < 0.05)，可溶性蛋白质和叶绿素含量，POD和SOD活性显著的降低(P < 0.05)，同时也使桢楠小苗叶片的光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用效率(WUE)和胞间CO₂浓度(Ci)和气孔限制值(Ls)下降。施用0.25 mmol/L SNP溶液后，MDA含量和气孔限制值(Ls)发生了显著的降低(P < 0.05)，可溶性蛋白和叶绿素含量，POD和SOD活性以及光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、水分利用效率(WUE)和胞间CO₂浓度(Ci)也发生了显著的提高(P < 0.05)。综合比较得出，0.25 mmol/L的SNP溶液是提高桢楠幼苗抗Pb²⁺胁迫能力的最佳处理。

Abstract: This paper explored the influence of different concentrations of exogenous NO donor SNP on physiological characteristics of Phoebe zhennan on Pb²⁺ stress. The results showed that the contents of MDA in leaves of Phoebe zhennan increased significantly (P < 0.05); the activities of POD and SOD, soluble protein and relative chlorophyll contents decreased obviously (P < 0.05), while the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), water use efficiency (WUE), intercellular CO₂ concentration (Ci) and stomatal limitation value(Ls) decreased under 900 mg/L Pb(NO₃)₂ at the same time．The contents of MDA and stomatal limitation value (Ls) of Phoebe zhennan seedlings were decreased significantly (P < 0.05) with adding 0.25 mmol/L sodium nitroprusside (SNP, nitric oxide donor), which stimulated greatly the contents of soluble protein, relative chlorophyll and the activities of POD, SOD at the same time, while raised the values of the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), water use efficiency (WUE), intercellular CO₂ concentration (Ci) significantly (P < 0.05). In conclusion, the most pronounced treatment concentration of SNP was 0.25 mmol/L.