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Diurnal and seasonal variations of non-photochemical quenching of chlorophyll fluorescence in sweet viburnum leaves

Wu Hai, Zhang Shuyuan, Xu Daquan, Guo Lianwang, Shen Yungang

Northwest Plateau Institute of Biology,The Chinese Academy of Sciences,　Xining 810001, Qinghai； China

Abstract

Diurnal and seasonal changes innon-photochemical quenching of chlor-ophyll fluorescence in sweet viburnum were observed with a modulated　fluorimeter,in order to explore the regularities of the radiationless energy dissipation under natural conditions.On clear days,non-photochemical quenching (q_(E)) and its slowly-relaxing component(q_(E-slow)) rose with an increase of sunlight intensity, and reached their maxima at noon, then declined with the decrease of sunlight intensity.On cloudy days,however,the changes of q_(E) and q_(E-slow) were not significant.The q_(E) and q_(E-slow) measured in winter were higher than those measured in spring and autumn. The q_(E) and q_(E-slow) measured at both high and low temperatures were higher than those measured at optimum temperature. These results indicate that the predominant factors causing the diurnal and seasonal changes in non-photochemical quenching of chlorophyll fluorescence in sweet viburnum are sunlight intensity and air temperature,respectively.

Key words: Chlorophyll fluorescence;Non-photochemical quenching;Diurnal variation;Seasonal variation;Radiationless energy dissipation;Sweet viburnum

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Citing This Article：

Wu Hai, Zhang Shuyuan, Xu Daquan, Guo Lianwang, Shen Yungang. Diurnal and seasonal variations of non-photochemical quenching of chlorophyll fluorescence in sweet viburnum leaves. Acta Physiol Sin 1997; 49 (2): (in Chinese with English abstract).