Abstract:

Spraying 1-2 mmol/L solution of NaHSO3 on rice (Oryza sativa L.) leaves resulted in the enhancement of net photosynthetic rate for more than three days. It was also observed that NaHSO3 application caused increases both in ATP content in leaves and the millisecond-delayed light emission of leaves. The increase in net photosynthetic rate caused by NaHSO3 treatment was similar to that by PMS (phenazine methosulfate) treatment. The grain yield of treated rice was enhanced approximately by 10% after duplicated application of NaHSO3 in milk-ripening stage. It is suggested that the enhancement of photosynthesis by NaHSO3 treatment resulted from the effect of increasing ATP supplement. Concomitant with an increase in the photosynthetic rate and ATP content in leaves, the transient increase in chlorophyll fluorescence after the termination of actinic light, which could be used as an index of the cyclic electron flow, was also enhanced by low concentration of NaHSO3 treatment. Basing on these results it is proposed that the increase in rice photosynthesis caused by low concentrations of NaHSO3 could be due to the stimulation of the cyclic electron flow around PSⅠwhich in turn the enhancement of the coupled photophosphorylation and photosynthesis.

低浓度NaHSO ₃促进田间水稻的光合磷酸化和光合作用
王宏炜¹ 魏家绵¹  沈允钢^1* 张荣铣² 杨图南³

（1. 中国科学院上海生命科学研究院植物生理研究所，上海00032；2.  南京农业大学水稻研究所，南京210095； 3. 江苏丘陵地区镇江农业科学研究所，江苏212400）

摘要：用1～2 mmol/L NaHSO3喷施于水稻(Oryza sativa L.)叶面可以提高叶片的光合速率,并能持续3 d以上.在此条件下,光下叶片中的ATP含量明显增高,叶片的叶绿素毫秒延迟荧光加强,反映与光合磷酸化活力有关的跨类囊体膜质子梯度增加.乳熟期喷施2次1 mmol/L NaHSO3后,水稻产量提高约10%.研究表明NaHSO3的主要作用和PMS(phenazine methosulfate)促进光合速率的原因可能类似,都是增加了ATP的供应.与此同时,观察到低浓度NaHSO3可促进水稻中反映循环电子传递的叶绿素荧光在作用光关闭后的短时上升.以上现象表明低浓度NaHSO3的促进作用很可能是通过促进围绕PSⅠ的循环电子传递及其耦联的光合磷酸化而促进水稻光合作用的.

关键词： 循环电子传递；毫秒延迟荧光；光合磷酸化；叶绿素荧光在作用光关闭后的短期上升

Key words: cyclic electron transport, millisecond delayed light emission, photophosphorylation, post-illumination transient increase in chlorophyll fluorescence