Effects of Drought Stress on Photosynthetic Characteristic and Growth of Jatropha curcas L.Seedlings

Water-controlling pot experiment was carried out to study the effects of drought stress on photosynthetic characteristic and growth of Jatropha curcas L.seedlings.The results showed that leaf relative water content(LRWC),height growth(△H),basal diameter growth(△D),net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs) were decreased with the increment of stress time.The water use efficiency(WUE) was increased under mild and moderate drought stress,and dramatically reduced under severe drought stress.The intercellular CO2 concentration(Ci) was decreased under mild and moderate drought stress,and markedly increased under severe drought.This indicated that the decrease of photosynthetic capacity of J.curcas L.seedling under mild and moderate drought stress is mainly due to stomatal limitation,while that under severe drought stress is mainly due to non-stomatal limitation.J.curcas L.seedling could accommodate mild and moderate drought stress environment and sustain life by decreasing Pn and Tr,and increasing WUE,and the growth became weaker on those conditions;however,it could be seriously limited by soil moisture under severe drought stress.