Research On Physiological Characters Of Nine Woody Plants Seedlings Under Waterlogging Stress

This paper dealt with the growth and physiological characters of1-year-old seedlings ofSapium sebiferum, Koelreuteria bipinnata var. integrifoliola, Broussonetia papyifera, Celtissinensis, Hibiscus mutabilis, Sapindus saponaria, Aesculus chinensis, Chaenomeles sinensis andEriobotrya japonica under different conditions of waterlogging stress. Some results had beengained as follows:1. After the course of waterlogging experiment, the seedlings of Koelreuteria bipinnata var.integrifoliola and Sapindus saponaria were all dead. The survival rates of the other7woodyplants were all100%, and there appeared hypertrophied lenticels and adventitious roots. Thoughseedlings of Koelreuteria bipinnata var. integrifoliola made their roots grow towards the surfaceof the ground, the amount of their adventitious roots were significantly less than the other7woody pants. The distribution of the hypertrophied lenticels of of Sapindus saponaria seedlingswere focused on the under-part of rhizome under the water surface. Sapium sebiferum, Celtissinensis and Eriobotrya japonica seedlings all survived, but the lower leaves were yellow andsome of them wilted. The surface of Eriobotrya japonica seedlings’ leaves mildewed, andChaenomeles sinensis seedlings’ leaves were water-soaked. Broussonetia papyifera, Hibiscusmutabilis and Aesculus chinensis seedlings were growing well, and there were no significantdifferences in external morphology compared with CK.2. At the early stage of waterlogging stress,9woody seedlings’ Pn, Gs and Ci had differentdegrees of decline. Compared with the trend of Pn and Gs, the change of Ci were more complex.Through the correlation analysis of Gs and Ci, the Pn decline of Celtis sinensis, Hibiscusmutabilis, Aesculus chinensis, Chaenomeles sinensis and Eriobotrya japonica was mainly due tostomatal limitation. The Pn decline of Broussonetia papyifera was mainly due to stomatallimitation, but there are also non-stomatal limitation. The Pn decline of Sapium sebiferum,Koelreuteria bipinnata var. integrifoliola and Sapindus saponaria was mainly due tonon-stomatal limitation which was because of the decrease in leaf photosynthetic capacity itself.3. Under waterlogging stress, Koelreuteria bipinnata var. integrifoliola and Sapindussaponaria seedlings’ SOD and POD activity decreased rapidly, which lead to the accumulation ofMDA and the increase of membrane relative conductivity. And the seedlings died at last. Sapiumsebiferum, Broussonetia papyifera, Celtis sinensis, Chaenomeles sinensis and Eriobotryajaponica seedlings’ POD activity were not maintained at a high level for a long time, whereChaenomeles sinensis and Eriobotrya japonica seedlings’ SOD activity also went overalldownward trend, and decreased significantly in the late waterlogging period. Which finally leadto the accumulation of MDA and the increase of membrane relative conductivity.4. By using principle component analysis and subordinative function, combined with theactual situation, the9woody plants according to their ability of waterlogging were divided into4groups. They are as follows: waterlogging resistance group (Hibiscus mutabilis, Aesculus chinensis), less waterlogging resistance group (Sapium sebiferum, Broussonetia papyifera, Celtissinensis), less waterlogging intolerance group (Chaenomeles sinensis, Eriobotrya japonica) andwaterlogging intolerance group (Koelreuteria bipinnata var. integrifoliola, Sapindus saponaria)...