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.