The Response Of Plant Propagation Bank To Water-level Change In The Wetland Of Poyang Lake

So far, as one of the world’s three bigecosystem, wetland ecosystem gave birth to a lot of plants and animals and microbes, wetland vegetation is the main producer of the wetland ecosystem. The role of palnt propagation bank(seed bank and bud bank) in the abolishment, succession and restoration of wetland vegetation has always been concerned in wetland science. Research on the responses of strategy and mechanism of plant propagation library to water level changes is the hot issue in the field of ecology. Water resources and hydrological changes periodically play an important role in the germination and growth of wetland palnt propagation bank, the response procedures and response mechanism of wetland palnt propagation bank to the water level changes is different, thus formed the different vegetation types. The dynamic change of wetland palnt propagation bank can insight into the succession of wetland plant community, and it will help manage ecological functions and process,answer hydrological process, ecosystem structure and provide scientific basis for its protection. This study selected the high fluctuation in water level of poyang lake wetland as the research object and carries on the preliminary study. Through the response strategy of wetland plant propagation bank to water level change, to research soil seed bank and bud bank through four or five transects along water gradient in three sample,the results are as follows:1) Through the seedling germination experiment, soil seed Banks were germination 20 families, 36 genera and 49 kinds, the dominant families including compositae, polygonaceae, cyperaceae, cruciferae, scrophulariaceae and gramineae. The huge numbe of soil seed Banks is 17328.6±1675.3 seeding / m2, the density of soil seed bank between the different water district is significant differences. Different levels of soil seed bank density of high and low order as: 0-5 cm(7821.4±801.7 seeding/m2) > 5-10 cm(5488.1 ±591.3 seeding/m2) > 10-15 cm(4019.0±541.0 seeding/m2).2) Through quadrat investigation and laboratory simulation research, bud bank has identified 6 families, 12 genera and 16 species, the dominant family including water turtle, cyperaceae, polygonaceae, and gramineae.The density of bud bank is 798.0±73.5 buds/m2, the density of bud bank between the different water district is significant differences, bud bank along the water gradient is increased first and then reduce.3) Based on the research of the wetland palnt propagation bank spatial distribution, found that the pecies composition and size of soil seed Bank and bud bank in the different water area have significant differences. The change of hydrological conditions directly affect the spatial distribution and size of wetland plant communities, the hydrological cycle is the main reason to cause soil seed Bank and bud bank form a cluster distribution.4) By gradient simulation, found that the water level are influence Poyang lake wetland soil seed bank and bud bank are obvious, the wetland palnt propagation bank based of flooded and bare has significant effect of response.Longer hydrological cycle will affect the growth of wetland palnt propagation bank base and germination, especially the water level rises, the submerged plant blooms, and the water level zones C may evolved into the submerged plant communities.