Physiological And Ecological Characteristics Of Tamarix Shrubs In Lop Nor Region And Its Response To Environmental Factors

The whole life process of plant growth and development is influenced by many environmental factors,among which the water is one of the most important factors affecting plant growth and development.Located in the hinterland of Eurasia,Xinjiang is the arid center of Eurasia and China,while Lop Nur is the driest region.The Lop Nur area has sparse rainfall,low vegetation coverage,strong wind-sand activity,and generally heavy soil salinity.In this particular harsh environment,Tamarix shows the strong adaptability,and its unique physiological and ecological characteristics enable it to survive in the severe ecological environment.The Tamarix shrubs in arid region contains abundant climate and environment information,and are ideal object for studying climate and environment change in desert area.In this paper,Tamarix shrubs naturally grown in Lop Nor region were taken as research sample.Four areas were selected in the study area.The morphological characteristics of Tamarisk shrubs,such as plant height,basic diameter and coverage were measured and the physiological indexes of the chlorophyll,proline,soluble protein,malondialdehyde and other physiological indicators that may have obvious responses to the environment were determined,To study differences of physiologicaland ecological characteristics of Tamarix shrubs under different ecological environments in Lop Nor region and their responses to environmental factors,The results provide a theoretical basis for further understanding the ecological environment in Lop Nor region and improving the quality of regional ecological environment.The main conclusions are as follows:(1)The morphological characteristics of Tamarix shrubs in different areas of Lop Nur have obvious differences.In different regions,the change trend of plant height and basic diameter of Tamarix shrubs is:Hongliugou > Lower reaches of Peacock River > Hongliujing > Milan;The coverage is: Milan > Lower reaches of Peacock River > Hongliujing;Form the same sampling area,the Tamarix cones did not formed in Hongliugou area,while in the lower reaches of Peacock River,Milan,Hongliujing and other areas,the Tamarix shrubs on the small cones grew better than the large cones,and the Tamarix shrubs have died or were buried by the wind-sand on some tall cones.(2)The contents of chlorophyll,proline,and soluble protein of Tamarix shrubs were significantly different in different areas of Lop Nor region,The overall change trends is: Hongliujing > Lower reaches of Peacock River > Milan > Hongliugou.proline and soluble protein of Tamarix play the role of osmotic adjustment to ensure the normal growth of Tamarix in arid environment.The overall performance of malondialdehyde contents in the four regions is: Hongliugou > Lower reaches of Peacock River > Milan > Hongliujing.(3)Under the combined influence of climate environmental factors such as moisture,Tamarix cone size,sand source,and temperature,the morphological characteristics of the Tamarix shrubs showed different.In the Hongliugou area,there is good water condition all year round,lacks of sand source,and there is no Tamarix cones,Tamarix forests appear arborization;The lower reaches of Peacock River is affected by ecological transported water,the Tamarix grows best and dense,and the average plant height and basic diameter are larger than those in Milan and the Hongliujing areas;In Hongliujing area,there is abundant groundwater recharge.Although the soil has high salt content,as a salt-tolerant plant,the average plant height and basic diameter of Tamarix shrubs living here are also large;Due to the deep groundwater level,strong wind-sandy activity,and cones is moving strongly,Tamarix shrubs are fully developed,There are many small cones,and the average plant height and basic diameter are small.The coverage of Tamarix on cones is greatly affected by the volume of Tamarix cones and wind-sandy activity.(4)Temperature is the main reason for the difference of in chlorophyll content of Tamarix in Lop Nor region.The chlorophyll content is higher in Hongliujing area with a higher annual average temperature,and the chlorophyll content is the lowest in Hongliugou area with a lower annual average temperature.The difference in the content of proline and soluble protein in the four areas is the result of the interaction of various environmental factors.The content is higher in the Hongliujing area where the stress is the highest,and lowest in Hongliugou area where the living conditions are the best and the stress damage is the smallest;The environmental change has little effect on the Malondialdehyde content of the Tamarix shrubs,and the content change is relatively stable.(5)The proline and soluble protein of the Tamarix shrubs together play an osmotic adjustment role in coping with the arid environment of Lop Nur.From the degree of response under the stress,the content of proline is the most sensitive physiological characteristic,which can be used as an optimal index for studying the response of Tamarix shrubs to environmental factors in Lop Nor region.