Effects Of Water Stress On Growth And Physiological Characters Of Sapium Sebiferum Roxb.

Sapium sebiferum Rox b. is a kind of fast-growing woody oil-bearing plant, which has the very high economic and ornamental value. The wetland and coastal interval account great proportion of the land area in our country. To study water-stress of sapium is essential to establish various sapium plantations.This paper dealt with the growth and physiological characters of 1-year-old seedlings of four provenances of Sapium sebiferum Rox b. (Tongxiang, Lanxi, Jiangxi, Fujian) under 4 conditions of water logging and flooding stress, some results had been gained as follows:1. Treatment B accelerated the growth of provenances of Sapium sebiferum Rox b. from Tongxiang, Lanxi, Jiangxi, but seriously inhibited the growth of Fujian. Under treatment C&D, there were no significant difference with control from out features in Tongxiang&Lanxi, and there appeared hypertrophied lenticels and adventitious roots at their stem base,but the leaves of Jiangxi&Fujian appeared purple splash and then fell off, the growth stagnated and dead, C&D treat seriously inhibited the increase of biomass to each provenances.2. With prolonged waterlogging, chlorophyll content, Pn and Gs gradually decreased in different degrees, but the changes of Ci were complex. Analysing the relationship between Gs and Ci, we concluded that the main cause for decrease of Pn in Tongxiang&Lanxi was the reduction of stomatal conductance under flooding and waterlogging stress, but for Jiangxi&Fujian, the main cause was non-stomatal limitation in the end of the treatment.3. Compared with control, flooding and waterlogging stress brought great changes in leaf plasm membrane permeability, protective enzymes activity, ROS and accumulation of MDA. The SOD activity of Tongxiang&Lanxi kept a high level while the values went down gradually of Jiangxi&Fujian under the stress. All provenances in all treatments had a lower POD activity and declined rapidly while the content of MDA, generation rate of O2-·, content of H2O2 increased with the elongation of time-course of waterlogging treatment.4. During the waterlogging, soluble protein increased firstly and then decreased, the content of proline was variance but lower than control, soluble sugar kept a high level in leaf of Tongxiang&Lanxi. However, soluble protein and soluble sugar showed a downtrend while content of proline higher than control of Jiangxi&Fujian.We compared with the activity of LDH and ADH between different provenances, concluded that provenances of Tongxiang & Lanxi can get necessary energy by both high level of ethanol fermentation and lactate fermentation under hypoxic stress whereas the leading pathway to get enough energy was lactate fermentation in the fist stage of waterlogging in Jiangxi & Fujian.5. By using principle component analysis and subordinative function to make comprehensive evaluation to different provenances ,the sequence of resisting to flooding stress was ranked as follows:Lanxi>Tongxiang>Jiangxi>Fujian.