Studies Of Water Stress On The Physiological Characteristic Of Pterocarya Stenoptera Seedlings From Different Provenances

The changes of morphological and physiological characteristics of Pterocarya stenoptera seedlings from Jiangning Jiangsu, Hefeng Hubei, Xiuning Anhui, Jiujiang Jiangxi, and Huoshan Anhui provenances were studied to reveal the physiological mechanisms of resistance to water-stress. The results were shown as follows:1. Effects of water stress on the external morphology of Pterocarya stenoptera seedlings were shown as: adventitious roots were produced on stems submerging in water under waterlogging stress, and the more the number of adventitious roots produced, the better the seedling grew. Wilting phenomenon appeared under drought stress. According to changes in the external morphology of Pterocarya stenoptera seedlings under water stress, Seedlings from Hefeng Hubei were the worst provenance in resistance to waterlogging and drought stress.2. The root vigor and root biomass of seedlings were declined under waterlogging stress, and photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate(Tr) of seedling leaves were reduced. The seedlings from Jiujiang Jiangxi and Jiangning Jiangsu provenance showed strongest resistance to submergence among five provenances.3. With the increasing time of stressing of waterlogging, the content of MDA in leaves of seedling form five provenances was shown a trend of increasing first and decreasing thereafter, contents of soluble sugar and proline in leaves gradually increased, and contents of soluble protein were maintained in a high level at the beginning of stress, then had a slow decline; the activity of SOD was the highest on the 6d of stress, and decreased gradually thereafter; the activity of POD decreased in the whole period of stress. There were no significant differences in physiological characteristics between surface and subsurface waterlogging stress.4. With the increasing time of stressing of drought stress, the content of MDA in leaves of seedlings form five provenance increased, the content of proline in the leaves had a rapid and continuous accumulation, soluble sugar contents, protein contents and POD activities remained at relatively high level, whose level remained unchanged basically, SOD activities declined and had a large decrease.