EFFECTS OF WATER-STRESS ON PHOTOCHEMICAL FUNCTION AND PROTEIN-METABOLISM OF PHOTOSYSTEM-II IN WHEAT LEAVES
EFFECTS OF WATER-STRESS ON PHOTOCHEMICAL FUNCTION AND PROTEIN-METABOLISM OF PHOTOSYSTEM-II IN WHEAT LEAVES
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DOI：
10.1111/j.1399-3054.1995.tb05130.x
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发表时间：
1995-04-01
影响因子：
6.4
通讯作者：
LIANG, HG
中科院分区：
文献类型：
--
作者：
HE, JX;WANG, J;LIANG, HG
研究了渗透脱水对小麦(Triticum aestivum L.cv.用分离的类囊体膜和PSII膜研究了龙春10号对PSII的光化学功能和蛋白质代谢的影响。结果表明，PSII对水分胁迫具有较强的抗性，叶片轻度缺水对其活性没有明显影响。然而，极端胁迫条件，如相对含水量(RWC)降低40%或水势(Psi(W))降低1.8 Mpa，PSII的释氧量减少约50%，DCIP(2，6-二氯苯酚)光还原抑制约25%。此外，还发现PSII的电子供体DPC(2，2-二苯基碳酰二肼)不能逆转受抑制的PSII的DCIP光还原，这表明水分胁迫并不影响对PSII的电子给予。尿素-SDS-PAGE和免疫印迹分析表明，主要PSII蛋白的稳态水平，包括PSII反应中心的DI和D2蛋白，随着水分胁迫的增加而下降，这可能是由于加速了降解。体外翻译实验和叶绿体RNAs的定量分析表明，水分胁迫降低了叶绿体蛋白质的合成能力。结果表明，水分胁迫对PSII蛋白代谢的影响，特别是对反应中心蛋白的影响，可能是造成PSII光化学损伤的原因之一。
The effects of osmotic dehydration in wheat leaves (Triticum aestivum L. cv. Long chun No. 10) on the photochemical function and protein metabolism of PSII were studied with isolated thylakoid and PSII membranes. The results indicated that PSII was rather resistant to water stress as mild water deficit in leaves did not significantly affect its activity. However, extreme stress conditions such as 40% decrease in relative water content (RWC) or 1.8 MPa in water potential (Psi(w)) caused ca 50% reduction in O-2 evolution and ca 25% inhibition of DCIP (2,6-dichlorophenol indophenol) photoreduction of PSII. In addition, it was found that the inhibited DCIP photoreduction of PSII could not be reversed by DPC (2,2-diphenylcarbazide), a typical electron donor to PSII, suggesting that water stress did not affect electron donation to PSII. Urea-SDS-PAGE and western blot analysis showed that the steady state levels of major PSII proteins, including the DI and D2 proteins in the PSII reaction center, declined on a chlorophyll basis with increasing water stress, possibly as a result of increased degradation. In vitro translation experiments and quantitative analysis of chloroplast RNAs indicated that the potential synthesis of chloroplast proteins from their mRNAs was impaired by water stress. From the results it is concluded that the effects of water stress on PSII protein metabolism, especially on the reaction center proteins, may account for the damage to PSII photochemistry.