一氧化氮改善铁胁迫玉米光合组织结构及其活性

Nitric oxide improves photosynthetic structure and activity in iron-deficient maize

一氧化氮(NO)影响植物生长发育过程及其机制是近年来的研究热点,在植物生长发育的多个层面起着重要的作用。以硝普钠(SNP)为一氧化氮发生剂,液体培养20 d龄的玉米幼苗叶片为实验材料进行研究,结果表明,NO可完全逆转玉米幼苗由缺铁引起的脉间失绿现象,极显著地提高叶片叶绿素含量。电镜观察结果证实,NO促进了玉米叶片叶肉细胞和维管束鞘细胞中叶绿体的发育,叶绿体数量增多且体积增大,基质片层和基粒数量明显增多且结构完好。同时,NO促进了缺铁玉米类囊体膜色素蛋白复合体的装配并显著提高了光合链的电子传递速率,使叶片光合活性得到极显著增加。

Nitric oxide （NO） plays an important role in growth and development of plants. In this study, we used Sodium Nitroprusside （SNP） as NO donor to examine the positive effect of NO on photosynthetic structure and its activity in irondeficient maize grown in nutrient solution for 20 days. The results showed that NO could completely reverse the interveinal chlorosis induced by iron deficiency and increase chlorophyll content in the leaves of maize seedlings. Electro microscope analysis showed that NO promoted the chloroplast development, as indicated by increased number and size of chloroplast in both the mesophyll cell and bundle sheath cell of the leaves, and well-developed stroma lamellae and grana as well as increased numbers. Further studies showed that the assembly of protein complexes of thylakoid membranes was significantly promoted and the electron transfer rates in thylakoids were enhanced by NO treatment, so the photosynthetic activity of leaves was obviously increased.