Study On Drought And Waterlogging Resistance Of Typical Plants In Yongding River Basin(Beijing Section)

The Yongding River is known as the "mother river" of Beijing.In recent years,the Yongding River has been degraded and the environment is harsh.Some rivers have been waterless for many years and the soil is seriously desertified.It has become a source of sand in Beijing.Through several field investigations and the search and reading of literature materials,four typical plants of Yongding River were selected for research,namely Tamarix,Imperatae,Lespedeza,and Sabina,at the same time,the adaptable strong Sedum lineare was selected as the introduced species.and the drought resistance and sorghum resistance of the five plants are studied.The plants suitable for planting in the Yongding River Basin are selected to improve the soil properties and improve the ecological environment.In this study,different water stress treatments(drought/flooding 0 d,drought/flooding 7 d,drought/flooding 14 d,drought/flooding 21 d,drought/flooding 28 d)were set up to observe the growth status and physiological indexes of plants.Determination of plant drought resistance and sorghum resistance by plant height,leaf chlorophyll content,superoxide dismutase(SOD)activity,and peroxide deuterase(POD)activity by external morphological changes.The component analysis method and the membership function value method in fuzzy mathematics are used to comprehensively evaluate plants,and the following results are obtained(1)Under drought stress,the plant's leaves gradually appear dry yellow and fall off phenomenon,the plant height growth of the five tested plants was inhibited to varying degrees.The growth of Lespedeza,Sedum lineare,Sabina and Imperalae was 76%,48.9%,48.4%,and 71.4%,respectively,under normal conditions,Tamarix appear dry under drought stress.Meanwhile,physiologically,the chlorophyll content of Lespedeza,Imperatae and Tamarix showed a trend of increasing first and then decreasing under drought stress,with an increase of 36.3%,10.4%and 10.11%respectively compared with the control group.The chlorophyll content of Sedum lineare showed a downward trend,reaching the lowest value at 28 days,which was 62.4%lower than that of the control.The chlorophyll content of Sabina is relatively flat during the whole drought stress.The activity of SOD and POD of the five tested plants increased first and then decreased.The SOD activity of Tamarix,Sedum lineare,Imperatae,Lespedeza and Sabina increased by 12.5%,4.6%,4.6%,33.5%and 13.01%,respectively.Compared with the control group,the POD activity of Tamarix,Sedum lineare,Imperatae,Lespedeza and Sabina increased by 11.88%,30.35%,17.6%,11.79%and 42.65%,respectively.(2)Under the stress of waterlogging,the leaves of plants gradually appear withered,yellow and falling off.The growth of plant height of the five tested plants is inhibited to varying degrees.The growth amounts of Lespedeza,Sedum lineare,Sabina,Tamarix and Imperatae are 45%,34%,38.7%,58.3%and 73.2%respectively under normal conditions.At the same time,under waterlogging stress,the chlorophyll content of Tamarix and Imperatae showed an increasing trend,which increased by 40.5%and 29.7%respectively compared with the control.The chlorophyll content of Sedum lineare showed a downward trend,which was 49%lower than that of the control.The chlorophyll content of Sabina and Lespedeza increased first and then decreased,which increased by 38.1%and 15.4%respectively compared with the control.In addition,the POD activity of Tamarix increased with the increase of waterlogging time,and the SOD and POD activity of the other four plants showed a trend of increasing first and then decreasing under waterlogging stress.Compared with the control group,the SOD activity of Tamarix,Sedum lineare,Imperatae,Lespedeza and Sabina increased by 41.72%,30.04%,34.69%,21.1%and 27.65%,respectively.Compared with the control group,the POD activity of Tamarix,Sedum lineare,Imperatae,Lespedeza and Sabina increased by 46.35%,36.4%,24.12%,25.35%and 11.32%,respectively.(3)This study used the methods of principal component analysis and membership function to comprehensively evaluate the five tested plants.The results of comprehensive evaluation indicated that the order of drought tolerance of five plants was:Lespedeza>Imperata>Tamarix>Sabina>Sedum lineare.The order of resistance to five plants from strong to weak is:Tamarix>Imperata>Lespedeza>Sabina>Sedum lineare.(4)The comprehensive evaluation and cluster analysis of the drought resistance and tolerance of five plant species were carried out.The results showed that the two plants of Tamarix and Imperata had strong drought and tolerance.It is recommended to plant Tamarix chinensis and Rhizoma Imperatae in Yongding River basin(Beijing section).