Comparative Physiological Studies On Alternanthera Philoxeroides And Orgza Sativa Under Osmotic Stress

Among all kinds of biotic and abiotic stresses, drought and salinity are the most serious ones which limit plant growth and crop yield in agriculture and their damages to crops exceed the sum of the other natural stresses. Drought stress and salinity stress belong to the osmotic stress. It is important to enhance the resistance of plants and crops to the stressed environment, especially to the drought and salt stresses. On the one hand it is helpful to develop the stressed environmental agriculture, on the other hand it may use the resistance plant in respect of friendly ecological environment.Alternanthera philoxeroides which is resistant to osmotic stress and Orgza sativa were used as the materials for these experiments. The physiological indexes including proline, betaine, MDA, SOD, POD, CAT, T-AOC and the histological structure changes in the leaves and roots of Alternanthera philoxeroides and Orgza sativa under the stresses were observed and analyzed.The results showed that the contents of osmolytes in Alternanthera philoxeroides such as proline and betaine increased obviously along with the time of osmotic treatment, while no obvious changes were detected in Orgza sativa. The activities of anti-oxidases of Alternanthera philoxeroides were much higher than that of Orgza sativa, the activities of SOD, POD and CAT increased significantly in Alternanthera philoxeroides, while they changed a little in Orgza sativa. The damages of the leaves and roots tissues in Alternanthera philoxeroides were lighter than that observed in Orgza sativa under osmotic stress. Influences of salt stress to Alternanthera philoxeroides and Orgza sativa were silimar to that of drought stress. Results obtained in present studies provide useful information to study resistant genes of plants and crops.