Abstract:

To explore the effect of calcium on increasing the productivity of Chinese fir plantations in the Southern forest region with low phosphorus, the hydroponic cultures with seven different Ca levels treatments were designed. A study was carried out on the different law of chlorophyll contents and chlorophyll fluorescence characteristics among different treatments during low phosphorus stress. The differences in chlorophyll contents of Chinese fir among different Ca levels treatments became significant gradually, with the prolonging of stress time. Compared with the phosphorus sufficiency group (CK), Ca had remarkable effects on delaying the degradation of chlorophyll and maintaining relatively high level of photosynthesis efficiency, especially Ca levels in treatment Ⅳ (2.0 mmol/L) and Ⅴ (1.0 mmol/L). Growing in treatment Ⅵ with no Ca and no P, PSⅡ reaction center of Chinese fir leaves were damaged most seriously. A certain concentration of Ca could effectively relieve the inhibitory effects of low phosphorus stress on Fm.