Research On Anatomical Structure And Ecological Adaptability Of Dominant Plants In Poyang Lake Wetland

The Poyang Lake wetland is perennially in the state of droughts and floods.When adapting to this environment, the morphological and anatomical character oftheir vegetative organs can not only adjust to drought conditions but also survive inwaterlogged environment. This paper aims to conduct a comparative study on themorphological and anatomical character of roots, stems and leaves of the16dominantplants which spread on high level waterside of Poyang Lake wetland, and explore theadaptability of certain dominant plants to Poyang Lake wetland environment by waterstress experiment. Main results are concluded as follows:1. Productive tissues and mechanical tissues of roots, stems and leaves ofdominant plants in Poyang Lake wetland developed to different degrees. Theyshowed strong drought resistance of the plants.2. Conducting tissues are relatively developed. Because of the differentdistribution of the dominant plants in Poyang Lake wetland and different moistureconditions they are in, there are huge disparities on develpment lecels of conductingtissues. Among all these plants, the number of vascular bundles of Poaceae and someCyperaceae plants are the biggest. Vascular bundles number inside stems of somedominant plants and the distribution of elevation are of negative corelation while thenumber and soil moisture content are of positive corelation. The number of vesselsand air cavities as well as distribution of elevation are both of positive corelation.3. During the process of adapting to the environment of Poyang Lake wetland,aeration tissues formed in leaves, stems and roots of the dominant plants that arecollected for the study, and then developed into an air channel connecting leaves,stems and roots of the plant, going top-down through the plant to make sure airtransported and stored in the plant. Aeration tissues in leaves are consisted of aircavities of mesophyll cells and spongy tissues and tiny air cavities in the vascularbundles. Aeration tissues in stems are more developed. They are consisted ofmedullary cavities, air cavities that scattered in parenchymatous tissues and aircavities in vascular bundles. Aeration tissues in roots are mainly consisted of air cavities beneath parenchymal cells in mesothelium. It is revealed by the study thatproportion of air cavities in stems and roots of dominant plants is closely related tothe moisture content of the soil where they distribute.4. Coefficient of variation of their leaves, stems and roots is relatively large.Main reason of that is the distribution elevation, water content of the ground anddifferences between species. However, the indexes are related, which meansmorphological and anatomical character of each vegetative organ of the plantobviously coevolved during the process of adapting to the special environment ofPoyang Lake wetland.5. Except for Polygonum criopolitanum, which are drowned in the experiment,with the increasing time of waterlogging, length, number, diameter of air cavity anddiameter of medullary cavity in stems of other dominant plants change to varyingdegrees. The overall scale of air cavities tends to increase with the increasing time ofwaterlogging. They are of positive correlation. The thickness of some mechanicaltissues, including collenchyma tissues in leaves, stems and roots decrease with theincreasing time of waterlogging. In responding to that, the conducting tissues of someCyperaceae and Poaceae plants, become more developed in order to transport morewater inside the plant. Thus it can be seen that by adjusting protective, mechanical,conducting, and aeration tissues, morphological and anatomical structure of thedominant plants in Poyang Lake wetland can help them fully adaptable to thewaterlogged condition.