外源一氧化氮对玉米幼苗抗低温胁迫的影响

利用盆栽试验,用不同浓度的外源NO处理低温胁迫下的玉米幼苗,研究外源NO对玉米幼苗抗低温胁迫的影响。结果表明:低温明显抑制了玉米幼苗的生长,与常温对照相比,玉米幼苗叶片相对含水量下降了46.7%,叶绿素含量降低了19.19%,细胞膜的通透性增大,相对电导率增加了44.2%,丙二醛(MDA)含量增加了35.1%,可溶性蛋白含量下降了22.0%,可溶性糖含量下降了72.3%;适当浓度的外源NO可缓解低温胁迫造成伤害,其中浓度为0.10 mmol·L-1SNP处理效果最明显,与低温对照相比,MDA含量和相对电导率分别减少了24.4%和11.1%,相对含水量、叶绿素含量、可溶性蛋白和可溶性糖含量分别增加了40.2%、11.0%、19.25%、123.0%;外源NO能有效改善低温胁迫下玉米幼苗的光合作用,其净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)均较低温胁迫条件下未加NO处理有明显的增加,细胞间隙CO2浓度(Ci)则明显下降。表明适当浓度的外源NO可以缓解低温胁迫对玉米幼苗生长的抑制效应。

Effects of exogenous nitric oxide on low temperature stress of maize seedlings

This study aims to evaluate the effects of exogenous NO on low temperature stress of maize seedlings under low temperature stress by pot experiment.The results showed that low temperature significantly inhibited the growth of maize seedlings.The relative water content,chlorophyll content,soluble protein content,soluble sugar content were decreased by 46.7％,19.19％,22.0％,72.3％,respectively under low temperature stress.The cell membrane permeability was increased,with the relative conductivity and malondialdehyde (MDA) content increased by 44.2％ and 35.1％.The appropriate concentration of exogenous NO can alleviate the damage caused by low temperature stress,especially at the concentration of 0.10 mmol· L-1 SNP.Under this optimization treatment,MDA content and relative conductivity were decreased by 24.4％ and 11.1％ but the relative water content,chlorophyll content,soluble protein and soluble sugar were increased by 40.2％,11.0％,19.25％ and 123.0％,respectively.The photosynthesis of maize seedling was effectively improved by exogenous NO under low temperature stress.Compared with the condition of without NO treatment,the net photosynthetic rate (Pn),stomatal conductance (Gs),transpiration rate (Tr) were significantly increased under low temperature stress,but the CO2 concentration (Ci) was obviously declined.These results suggested that appropriate application of exogenous NO could relieve the inhibitory effect of maize seedling growth under low temperature stress.