Study On The Effect Of Water Level Changes On The Physiology And Ecology Of The Submerged Plant Potamogeton Crispus

Water level changes are the normal state of wetland hydrology,which plays an important role in the growth of submerged plants.Submerged plants have different response mechanisms under different water levels.Studying the physiological and ecological characteristics of submerged plants under different water level changes will help us to provide a reference basis for selecting appropriate plants for the ecological restoration of degraded wetlands.In this study,exploring the response and adaptation mechanism of Potamogeton crispus to different water level changes,the effects of water level and its changes on P.crispus were taken as the main research content,which provides reference strategies for the restoration of wetland.The main results are as follows:（1）In different gradient water levels,the growth of P.crispus generally formed a change trend of first rising and then falling with the increase of water level.P.crispus grow best in the range of 105～120cm water level.In the range of 50～90cm water level,P.crispus grow greatly under water level stress,and the growth state is obviously poor.In the 135cm water level group,P.crispus grow slightly under high water level stress,and the plant height of the 120cm water level group grows rapidly and reaches the maximum during the whole experiment period.The growth indicators that leaf number and biomass under different water level gradients reached a high value at the water level of 105～120cm.The differences between physiological indicators such as photosynthetic pigment,SOD,POD,CAT,O₂^-,and MDA were small,and there was no obvious change.（2）Under the condition of rising water level,the overall growth trend of P.crispus increased with the increase of treatment intensity;Under the condition of falling water level,the overall growth trend of P.crispus increased first and then decreased with the increase of treatment intensity.It is embodied in morphological and physiological characteristics.The plant height,leaf number and biomass of P.crispus reached a high value in the 1.4-1.7 cm/d intensity treatment group under the condition of rising water level.The growth index of P.crispus reached a high value in the 1.4cm/d intensity treatment group under the water level drop condition,and the growth index had a significant downward trend in the 1.7cm/d intensity treatment group.However,whether it is rising or falling water level conditions,the common characteristics of the physiological characteristics of P.crispus are:the antioxidant system ability of P.crispus is limited by time,the ability to remove reactive oxygen species in the later stage of the test is weakened,the membrane peroxidation of the cells of P.crispus is serious,the leaves are yellow and rotten,and this feature is more obvious in the falling water level conditions,indicating that the rising water level conditions are more suitable for the growth of the P.crispus.（3）The morphological plasticity of P.crispus is shown that the plasticity of plant height was better than leaf number and leaf number is better than biomass,among which the water level of plant height plasticity was better than that of different gradients,the water level of different gradients of leaf number plasticity was better than the rising/falling water level,and the rising water level of biomass plasticity was better than that of different gradient water levels and better than the falling water level.The overall physiological plasticity was higher than the morphological plasticity,and the root vitality of plasticity was the highest.The morphological plasticity and physiological plasticity of P.crispus are different under different water level conditions,and the morphological characteristics of P.crispus are more affected by the change of water level and more obvious.