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叶绿素缺乏的大麦突变体的光合作用和叶绿素荧光

谭新星, 许大全, 汤泽生

中科院上海植物生理研究所.上海 200032；四川师范学院生物系.四川,南充 637002

摘要

和早熟3号大麦(野生型)(DG)相比,黄化大麦(突变体)(LG)叶片Chl含量低,而Chl a/b 较高;光合速率低,表观量子效率低,而饱和光强较高,气孔导度较高;荧光参数Fo低,而PSⅡ的光化学效率(Fv/Fm)以及T_(1/2)、Fm/Fo、#phi#e均高。以单位叶绿素计算,黄化大麦的PSⅡ电子传递活性和全链电子传递活性较高,而PSⅠ电子传递活性较低。推测黄化大麦PSⅡ的光化学效率增高可能是由于其PSⅡ向PSⅠ传递的激发能较少,是对Chl含量低的一种补偿。

关键词： 光合作用; 叶绿素荧光; PSⅡ光化学效率; 叶绿素缺乏的突变体; 大麦

Leaf photosynthesis and chlorophy11 fluorescence in a chlorophy11-deficient mutant of barley

Tan Xinxing, Xu Daquan, Tang Zesheng

Shanghai Institute of Plant Physiology,The Chinese Academy of Sciences.Shanghai 200032；China

Abstract

A comparative study of barley leaf photosynthesis and chlorophy11 fluorescence was made between a Chl-deficient mutant (with light green leaf,LG) and its wild-type (dark green leaf,DG) in order to further explore the regulatory mechanism of photosynthesis.As compared with DG,LG had a lower net photosynthesis rate (Pn) and apparent quantum yield (AQY), but a higher stomatal conductance, indicating that the lower Pn of LG may result from lower Chl (Chl a and Chl b) content, but not from lower stomatal conductance.PSⅡ photochemical efficiency (Fv/Fm) was about 10% higher in LG than in DG, which is different from the chlorophy11 b-less mutant of barley reported by Leverenz et al. (1992). Furthermore, LG had higher Chl a/Chl b ratio, a relative larger PQ pool, as indicated by fluorescence parameter T_(1/2), and a higher PSⅡ electron transport (H_(2)O_(2)→DMBQ) rate as well as whole chain electron transport (H_(2)O_(2)→MV) rate, but a lower PSⅠ electron transport (DCPIP→MV) rate when expressed in unit Chl(Table 4). From these results, it is deduced that the higher PSⅡ photochemical efficiency in LG results from the less excittation energy transfer from PSⅡ to PSⅠ, which may compensate the lower light harvest capacity due to Chl deficiency.High light (about 1 700#mu#mol photons m~(-1)s~(_1)) treatment resulted in a smaller decrease of Fv/Fm in LG than in DG, indicating that the mutant is less sensitive to photoinhibition conditions, Which is contrary to that of chlorophy11-deficient mutant of soybean reported by Xu et al.(1993).

Key words: Photosynthesis;Chlorophyll fluorescence;PS Ⅱ photochemical efficiency;Chlorophyll-deficient mutant;Barley

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引用本文：

谭新星, 许大全, 汤泽生. 叶绿素缺乏的大麦突变体的光合作用和叶绿素荧光[J]. 生理学报 1996; 48 (1): .

Tan Xinxing, Xu Daquan, Tang Zesheng. Leaf photosynthesis and chlorophy11 fluorescence in a chlorophy11-deficient mutant of barley. Acta Physiol Sin 1996; 48 (1): (in Chinese with English abstract).