Effects of light intensity on growth and physiological characteristics of Sedum sarmentosum during establishment stage

Effects of different light intensities (100%, 77%, 47% and 23% sunlight) on growth and physiological characteristics of Sedum sarmentosum during establishment stage were studied through artificially shading treatment. The results indicated that within the light intensity range in this experiment, S.sarmentosum could grow normally and showed good morphological plasticity. Low light intensity induced more new shoots and leaves, smaller diameter, longer shoot and internode. Compared with 100% sunlight, shading promoted plant dry matter accumulation and more energy distribution to the growth of stem. All these changes help capture more light to adapt to low light enviorenment. In addition, shading increased plant water content and soluble protein content, and reduced soluble sugar content. Photosynthetic pigment content increased significantly only on 23% sunlight condition which caused dramatic negative influence to root development, and slight decrease of plant dry weight contrasting to 47% sunlight. It suggested that moderate shading could accelerate covering rate in establishment, but light intensity lower than 23% was not recommended.