Effects of light-regulation and intensity on the growth, physiological and biochemical properties of Aralia elata (miq.) seedlings

The effects of different shading treatments (i.e. 50%, 65%, and 80% shading) on the growth, physiological and biochemical properties of one-year-old Aralia elata seedlings were studied. Different simulated illumination conditions showed remarkable impact on the growth and physiological attributes of A. elata. Decrease in the simulated illumination intensity caused the growth of A. elata to increase gradually, reaching maximum growth under 65% shading on the 45th day. Chlorophyll a, chlorophyll b and total chlorophyll significantly reduced as compared to treatments under 80% shading. Chlorophyll contents of 50% and 65% shaded plants were markedly higher (p < .05) as compared to 80% shaded and control plants on the 45th day. The leaf protective enzyme activities and resistance indexes such as malonaldehyde and proline content prominently enhanced in 80% shading treatment compared to other shading treatments and the control group (no shading). Low light regime led to a decrease in the soluble sugar and protein content in A. elata. The soluble protein content was maximum under 65% shading i.e. 65% shading is more favorable for the normal growth and development of A. elata, while 80% shading has a lethal inhibitory effect on the growth of A. elata. Therefore, proper shading conditions should be handled wisely for optimum growth of A. elata seedlings. (C) 2018 SAAB. Published by Elsevier B.V. All rights reserved.