Adaptive strategies of adult Platycladus orientalis and Robinia pseudoacacia to spring drought
In the present study,the effects of spring drought stress on morphology and physiological characteristics of leaves and roots of mature Platycladus orientalis and Robinia pseudoacacia were analyzed and the adaptive strategies of the two tree species under drought stress were compared.The results showed that the proline and soluble protein contents,and SOD and POD activities in leaves of P.orientalis were significantly lower than those in leaves of R.pseudoacacia (P<0.05),but the soluble sugar content and CAT activity in leaves of P.orientalis were significantly higher than those in leaves of R.pseudoacacia under spring drought stress (P < 0.05).Meanwhile,the difference in malondialdehyde content in leaves was not significant between P.orientalis and R.pseudoacacia (P>0.05).The proline and soluble protein contents,and POD and CAT activities in roots of P.orientalis were significantly lower than those in roots of R.pseudoacacia (P<O.05).However,the soluble sugar and malondialdehyde contents in roots of P.orientalis were significantly higher than those in roots of R.pseudoacacia (P<0.05).The specific leaf weight and root activity of P.orientalis were significantly higher than those of R.pseudoacacia (P<0.05).The root length density and root area index of R.pseudoacacia were significantly greater than those of P.orientalis (P<0.05).These results indicated that there were differences in permeating substance contents and antioxidative enzyme activities between P.orientalis and R.pseudoacacia under spring drought stress.The damages of spring drought to leaves were similar between P.orientalis and R.pseudoacacia,but the damages were more severe to the roots of P.orientalis.Adult P.orientalis mainly adopted drought-tolerance strategies,while mature R.Pseudoacacia mainly adopted drought-avoidance strategies under spring drought.
spring droughtadaptive strategymature treedrought tolerancedrought avoidance