Effects of shading on Capsicum chinense Jacq. seedlings in summer and autumn.

[Objective] The proper shading rate and timing for Capsicum chinense Jacq. cultivation in tropical area were explored to provide references for its production in Hainan Province. % Method ] Four shading rates of 30% (T3), 50 % (T5), 70% (T7) and 90% (T9) were set with no shading as the control to explore effects of different shading rate on Capsicum chinense Jacq. seedlings in summer and autumn in tropical area based on the analysis on morphological indexes, seedling index, chlorophyll content, soluble protein and Fv/Fm. [Result]The results showed that morphological indexes, seedling index, chlorophyll content and Fv/Fm declined with increased shading rate. Pn was the biggest in T3 during peak time of photosynthesis, demonstrating an inhibitory effect in photosynthesis caused by excessive or less PPFD. Plant height, stem diameter, photosynthetic product, seedling index, chlorophyll content, soluble sugar and Fv/Fm in CK were significantly higher than those in T5, T7 and T9 (P<0.05,the same hereinafter). Relative permeability of plasma in T5, T7, T9 and CK was significantly higher than that in T3 while proline was significantly lower in T5, T7, T9 and CK than that in T3. [Conclusion]A shading net with shading rate of 30% is recommended at noon to alleviate high light intensity damage in Capsicum chinense Jacq. and cultivate vigorous seedlings in summer and autumn. [ABSTRACT FROM AUTHOR]