Effects of salt stress on the structure and function of the photosynthetic apparatus in Cucumis sativus and its protection by exogenous putrescine
Effects of salt stress on the structure and function of the photosynthetic apparatus in Cucumis sativus and its protection by exogenous putrescine
复制标题
盐胁迫对黄瓜光合器官结构和功能的影响及外源腐胺的保护
DOI：
10.1111/j.1399-3054.2012.01623.x
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发表时间：
2012-11-01
影响因子：
6.4
通讯作者：
Yuan, Ling-Yun
中科院分区：
文献类型：
--
作者：
Shu, Sheng;Guo, Shi-Rong;Yuan, Ling-Yun
为了阐明多胺（PAs）在光合机构中的生理意义，研究了盐胁迫下叶面施腐胺（Put）和不施腐胺（Put）对黄瓜光合机构结构和功能的影响。75 mM NaCl盐胁迫7 d导致光合作用严重降低。快速叶绿素荧光瞬态分析表明，盐胁迫抑制了PSII光化学的最大量子产率（Fv/Fm），主要是由于PSII受体侧的损伤。此外，盐胁迫降低了活性反应中心的密度，降低了结构性能。显微分析表明，盐胁迫导致叶绿体包膜破坏，质体舌数量增加，类囊体膜畸变。此外，盐胁迫导致类囊体膜内源PAs含量降低，尤其是亚精胺和精胺的共轭和结合形式。然而，施用8 mM Put可缓解盐胁迫导致的净光合速率（Pn）和PSII实际效率（FPSII）的下降。在类囊体膜中加入更多的PAs，克服了盐胁迫对盐胁迫植物叶片光合器官结构和功能的破坏作用。对照植株施用后，既不增加类囊体膜PAs含量，也不影响光合作用。这些结果表明叶绿体中的PAs在保护类囊体膜免受盐胁迫的有害影响方面起着至关重要的作用。此外，目前的结果表明，盐诱导的光合作用功能障碍很大程度上可归因于光合机构中PAs的损失。
With the objective to clarify the physiological significance of polyamines (PAs) in the photosynthetic apparatus, the present study investigated the effects of salt stress with and without foliar application of putrescine (Put) on the structure and function of the photosynthetic apparatus in cucumber. Salt stress at 75 mM NaCl for 7 days resulted in a severe reduction of photosynthesis. The fast chlorophyll afluorescence transient analysis showed that salt stress inhibited the maximum quantum yield of PSII photochemistry (Fv/Fm), mainly due to damage at the receptor side of PSII. In addition, salt stress decreased the density of active reaction centers and the structure performance. The microscopic analysis revealed that salt stress-induced destruction of the chloroplast envelope and increased the number of plastoglobuli along with aberrations in thylakoid membranes. Besides, salt stress caused a decrease in the content of endogenous PAs, conjugated and bound forms of spermidine and spermine in particular, in thylakoid membranes. However, applications of 8 mM Put alleviated the salt stress-mediated decrease in net photosynthetic rates (Pn) and actual efficiency of PSII (FPSII). Put increased PAs in thylakoid membranes and overcame the damaging effects of salt stress on the structure and function of the photosynthetic apparatus in salt-stressed plant leaves. Put application to control plants neither increased PAs in thylakoid membranes nor affected photosynthesis. These results indicate that PAs in chloroplasts play crucial roles in protecting the thylakoid membranes against the deleterious influences of salt stress. In addition, the present results point to the probability that the salt-induced dysfunction of photosynthesis is largely attributable to the loss of PAs in the photosynthetic apparatus.