两种基因型小麦光合作用对NaHSO_3响应的差别(英文)

Difference in Response of Photosynthesis to Bisulfite Between Two Wheat Genotypes

两种不同基因型小麦京 41 1 (J41 1 ,北京地区高产小麦品种 )和小偃 5 4 (X5 4 ,一种远源杂交品种 )的光合作用对低浓度NaHSO3处理的响应不同。NaHSO31mmol/L处理能够提高京 41 1在CO2 浓度为 3 5 0和 90 0 μL/L的空气中的净光合速率 ;而对小偃 5 4 ,在这两种情况下的净光合速率均无明显影响。以往的研究表明NaHSO3促进光合作用的原因类似于PMS(phenazinemethosulfate) ,都是增加了ATP的合成。此文再次证明并发现经过NaH SO31mmol/L处理后 ,京 41 1叶片作用光关闭后叶绿素荧光瞬时上升的幅度提高 ,远红光后P70 0 +(reactioncenterchlorophyllofPSI)再还原的半时间缩短 ,表明NaHSO3可以促进小麦京 41 1中围绕PSI循环电子传递及其耦联的磷酸化。然而 ,NaHSO3对小偃 5 4的作用光关闭后叶绿素荧光瞬时上升的幅度及远红光后P70 0 +再还原的半时间均无明显影响。与小麦京 41 1相比较 ,小偃 5 4的作用光停止后叶绿素荧光瞬时上升的幅度增大 ,而且其在远红光后P70 0 +再还原的半时间更短 ,表明小偃 5 4的循环电子传递的能力远高于京 41 1的。两种不同基因型小麦对NaHSO3的响应不同很可能是由于二者在循环电子传递能力上有很大的差别。

Two wheat genotypes, Jing 411(J411, a high-yield cultivar cultivated around Beijing area) and Xiaoyan 54 (X54, a wheat cultivar formed by crossing Triticum aestivum L. with Elytrigia elongatiformis), were found to give different responses of photosynthesis to treatment with low concentration of sodium bisulfite (NaHSO 3). Bisulfite 1 mmol/L increased net photosynthetic rate (Pn) in wheat J411 under CO 2 concentrations of both 350 and 900 μL/L, but there was no significant enhancement of Pn in wheat X54 under either condition. In previous studies the effects of bisulfite in increasing Pn in wheat J411 and rice have been shown to be similar to that of PMS, both through an increase in the supply of ATP and this has been confirmed and investigated in the present study in wheat J411. In parallel with the increases in Pn and ATP content, the post-illumination transient increase in chlorophyll fluorescence was enhanced and the half-time of re-reduction of P700 + after illumination with far-red light was significantly shortened in leaves of wheat J411 after treatment with bisulfite 1 mmol/L, indicating that cyclic electron flow around PSI and the coupled photophosphorylation (PSP) were accelerated. In contrast, bisulfite had no effect on either the post-illumination transient increase in chlorophyll fluorescence or the half-time of re-reduction of P700 + after a far-red light in wheat X54. It was also found that the intensity of the post-illumination transient increase in chlorophyll fluorescence was much higher, and the half-time of re-reduction of P700 + was much shorter in wheat X54 than those in J411, suggesting that wheat X54 had higher intrinsic cyclic electron transport around PSI than that in J411. Basing on these results, it is suggested that the enhancement of Pn in higher plants by low concentrations of bisulfite solution might be due to the stimulation of cyclic electron flow around PSI and hence the PSP coupled to it. The difference in response to bisulfite between the two wheat genotypes could be attributed to the significant difference in rate of intrinsic cyclic electron transport around PSI between them.