外源抗坏血酸对臭氧胁迫下水稻光合及生长参数的影响

为研究臭氧浓度变化对水稻生长的影响及外源抗坏血酸的防护作用,在田间原位条件下,利用开顶式气室(OTCs)研究了外源抗坏血酸对O3胁迫下水稻光合及生长参数的影响.结果表明:在O3胁迫下,叶片的光合色素含量、气体交换参数、净同化率、相对生长速率及粒/叶面积(cm2)均显著下降;喷施外源抗坏血酸后,叶绿素a含量、叶绿素a/叶绿素b以及水稻叶片的光合速率、蒸腾速率显著升高,而叶绿素b含量和气孔导度变化不显著;外源抗坏血酸对O3胁迫下水稻的净同化率、相对生长速率及粒/叶面积(cm2)影响比较显著,特别是粒/叶面积(cm2)的提高有利于水稻源、库协调发展,为提高水稻产量和改进品质奠定了物质基础.

Effect of exogenous ascorbic acid on photosynthesis and growth of rice under O3 stress

To clarify the effect of changing troposphere ozone (O₃) concentration on rice growth and inhibiting effect of exogenous ascorbic, the effect of exogenous ascorbic acid (ExAsA) on rice photosynthesis and growth under O₃ stress was investigated using open-top chamber (OTC) in rice field. Analysis shows that photosynthetic pigment contents, gas exchange parameters, net assimilation rate (NAR), relative growth rate (RGR), and grain/leaf area ratio of rice notably decrease under O₃ stress. Chlorophyll a (chl a) level, chl a/chl b ratio, photosynthetic rate (Pn), and transpiration rate (Tr) significantly increase, whereas chl b and stomatal conductance (Gs) have no obvious change after ExAsA application. The effect of ExAsA on NAR, RGA, and grain/leaf area ratio is notable under O₃ stress, and is especially remarkable for grain/leaf area ratio. This demonstrates beneficial effect on coordinated development of source and sink, which forms the basis for improving rice yield and quality.