Recovery of the Photosynthetic Apparatus in Bean Plants after High- and Low-temperature Induced Photoinhibition *
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چکیده
The recovery after photoinhibition in 20-day-old bean plants (Phaseolus vulgaris L.) induced by 4 h treatment with low (12°C), normal (24°C) and high (42°C) temperatures under high (1000 μmol.m–2.s–1) and low (100 μmol.m–2.s–1) photon flux density (PFD) was studied. The changes in the photosynthetic apparatus were analysed using chlorophyll fluorescence measurements. The ratios Fv/Fm measured by PAM fluorimeter were used as characteristics of quantum efficiency of photosystem II. Data showed that both high and low temperatures enhance the photoinhibition manifested as Fv/Fm decrease. At all temperatures investigated this decrease was due in greater extent to Fm decrease while the increases in Fo were insignificant. Different pattern of photosynthetic apparatus recovery after photoinhibition at various temperatures was observed, suggesting that different mechanisms of photoinhibitory injury predominate in these cases.
منابع مشابه
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تاریخ انتشار 2000