Abstract:

There were four doublets in the Mössbauer spectrum of cucumber ( Cucumis sativus L.) photosystemⅡ (PSⅡ) particles. According to the value of isomer shift and quadrupole splitting, they represented oxidized cytochrome b559 (Cyt-b559), reduced Cyt-b559, Fe3+-quinone (Q) complex, and Fe2+-Q complex respectively. After water-stress, the electron transport rate between QA (primary quinone electron acceptor of PSⅡ)/QB(secondary quinone electron acceptor of PSⅡ) was affected and the absorption doublets of Fe2+ disappeared, suggesting that the reduced Cyt-b559 and Fe2+-Q complex had been oxidized. The results indicated that water-stress had changed the redox status of iron in the iron-quinone complex. Iron took part in electron transport through the change from a state of reduction to oxidation.

干旱胁迫对黄瓜PSII颗粒铁组分Mossbauer谱的影响
曾福礼¹ 吴劲松¹ 张丽静¹ 王建波² 周荣洁² 张明凤^3*

（兰州大学，生物系1，物理系2，化学系3，兰州730000）

摘要：黄瓜（Ｇｃｕｍｉｓ ｓａｔｉｖｕｓ Ｌ）叶片ＰＳⅡ颗粒的Ｍｏｓｓｂａｕｅｒ谱呈现４套双峰，依它们的化学位移相四敬矩劈塑数值，分别属于氧化态Ｃｙｔ－ｂ５５９，还原态Ｃｙｌ－ｂ５５９、Ｆｅ３＋－Ｑ画物和Ｆｅ２＋－Ｑ复合物。干埋胁迫旱影响ＱＡ／ＱＢ中铁（Ｆｅ）参与电子传递的速率，使ＰＳⅡ颗粒的Mｏｓｓｂａｕｅｔ谱中Ｆｅ２＋的吸收双峰消失，即还原态Ｇ７ｙｔ－Ｂ５５９转变为氧化态Ｃｙｔ－ｂ５５９Ｆｅ２-Q复合物转变为Fe3+-Q复合物。结果干旱胁迫改变了铁醌复合物中的铁存在状态，使铁具有氧化6还原态变化，从而参与电子传递。

关键词： 黄瓜；PSII颗粒；Mossbauer谱；Fe-Q复合物；干旱胁迫

Key words: cucumber, PSⅡ particles, Mö, ssbauer spectrum, Fe-quinone complex, water stress