EFFECTS OF Ca(NO3)(2) ON GREENHOUSE PEPPER GROWTH DURING PLUM RAINY SEASON IN CHINESE YANGTZE RIVER DELTA

Summer plum rainy season of Chinese Yangtze river delta has a unique weather, during that time it is hot and wet with around average air temperature of 30 degrees C, severely inhibiting the productivity of greenhouse cultivation. Moreover, soil salinization, a problem more and more widely, faced by Chinese protected cultivation is caused by the enrichment of Ca(NO3)(2) (CN), but not NaCl. And literature worldwide lacks works on whatever the impacts of Chinese summer plum rainy season or CN on the growth and photosynthetic capacity of greenhouse plant. Therefore, the aim of this study was to explore the effect of CN on growth, photosynthetic capacity, and yield of peppers grown in greenhouse in summer plum rainy season of Chinese Yangtze river delta. In this work, a pot experiment was conducted to investigate the effects of different CN concentrations (0, 50, 100, 150, 200 mM) on flowering pepper grown in greenhouse under the summer plum rainy environment. Results showed that: the average fruit dry weight (DW) and fruit number of per plant treated with 50 mM CN were the highest, with 55.85% and 12.90%, respectively, higher than the control. Fv/Fm of plants exposed to 50 mM CN was stable all the time. After 35 d, Y(II), qL, ETR and NPQ of plants exposed to 50 mM CN were the highest, showing the best photosynthetic performance. The results indicate that in summer plum rainy season, yield of pepper and the stability of leaf photosynthetic structure would be effectively maintained by providing low concentration CN. Our results also suggested that the optimum CN concentration was 50 mM; Y (II), ETR, qL, and Fv/Fm can be used to estimate plant growth situation under different CN concentration during plum rainy season.