低温对弱光影响甜椒光合作用的胁迫效应

以弱光耐受性不同的甜椒(Capsicumannuum L.)幼苗为材料,研究弱光低温逆境下及其恢复过程中叶片光合特性、PSⅡ光化学活性和吸收光能分配的变化。结果表明,弱光低温及弱光适温处理均导致甜椒净光合速率(Pn)、PSⅡ光化学效率(ФPSⅡ)和光化学猝灭系数(qP)明显下降,PSⅡ光化学反应中心能量(P)显著减少,天线耗散(D),尤其是反应中心能量耗散(Ex)显著增加。弱光低温或弱光适温处理下Pn的下降是非气孔限制的结果,低温降低了植株的弱光耐受性。光温逆境解除后,甜椒光合碳同化的恢复滞后于PSⅡ光化学效率的恢复,并且弱光下不同试材对低温的耐受性有所不同。

EFFECTS OF LOW TEMPERATURE ON PHOTOSYNTHESIS OF SWEET PEPPER UNDER LOW LIGHT

The changes of photosynthetic characters including photosynthetic gas exchange,chlorophyll fluorescence and absorbed light allocation in seedlings of different sweet pepper under low light and lower temperature stress and their recovery were studied.The result showed that in sweet pepper plants treatment with lower temperature(15℃/8℃) or optimal temperature(25℃/15℃) under low light,the net photosynthetic rate(Pn),actual photochemical efficiency of PSⅡin the light(Ф_(PSⅡ)),photochemical quenching(qP) and excitation energy to PSⅡphotochemistry(P) decreased,but antenna heat dissipation(D) and excessive energy(Ex) increased.The decrease of Pn under low light and lower temperature or optimal temperature was consider as a result of non-stomata restriction.The lower temperature reduced the tolerance-low-light of photosynthesis of sweet pepper leaves.Without low light and lower temperature stress,the carbon assimilation recovery of sweet pepper was found distinctly slower than photochemical efficiency of PSⅡ recovery.It also indicated that the tolerant capability of photosynthesis to low temperature and/or low light was different in different sweet pepper varieties.