Effects of shading on growth and physiological characteristics of Camellia japonica seedlings.

The effects of light transmittca degrees(100%,48.5%,22.4%) on the growth and physiological characteristics of Camellia japonica 'Helen Bower' were examined.The results indicated during the time from June to August,the plant height increased with the decrease in light transmittca degrees;but there was no significant difference in diameter.In high temperature stage in summer,the photosynthetic rate,stomatal conductance,intercellular space and concentration of CO2 were the highest under 48.5% transmittca degree.Under 22.4% degree,the stomatal conductance and intercellular space and concentration of CO2 decreased;the transpiration rate had no significant difference in three treatments.With the decrease of light intensity,the plants treated by shading showed that the water content of leaf increased and special leaf weight decreased remarkably.The contents of chlorophyll increased and leaf color greener,but soluble protein content and soluble sugar content decreased with the decrease in light transmittca degree.Therefore,48.5% light transmittca degree was advantageous to the growth and photosynthesis of C.japonica in high temperature stage in summer.