Physiological Properties and Growth of Cinnamomum camphora Saplings under Drought Stress and Rewatering
A pot experiment was conducted to investigate the effects of continuously drought stress(stopped watering for 0 d,2 d,4 d,…16 d,respectively) and rewatering on the growth and physiological properties of Cinnamomum camphora.The results showed that:(1) The diameter increment (Zd) and the height increment(Zh) were both inhibited under drought stress,Leaf relative water content(LRWC) under mild and moderate drought(stopped watering for 2-8 d and soil volumetric water content(SWC) decreased to 7％) were not significantly lower than that in control (D0),but significantly lower than those under severe drought(stopped watering for more than 10 d and soil volumetric water content decreased to 3％).(2)The concentration of O; and H2O2 significantly increased under severe drought stress.(3)The activities of superoxide dismutase(SOD) and peroxidase(POD) were promoted significantly during mild and moderate drought stress while catalase(CAT) activity increased significantly in severe drought stress,After rewater ing for 48 h,the activities of these three enzymes decreased.(4)The contents of malondialdehyde(MDA) and proline(Pro) increased significantly under severe drought.(5)The contents of soluble protein(SP) increased dramatically under mild drought,while that of soluble sugar(SS) raised significantly under moderate drought.Both of them then did not decreased,after rewatering for 48 h.The study suggests that C.camphora saplings under mild drought maintained normal growth through ROS scavenging system and osmotic adjustment,while suffered from moderate and severe drought stress,the water physiology became deteriorated,membrane system was injured,enzyme activities affected,and at last the morphological growth and aboveground biomass were depressed by the drought stress.
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