| Through the analysis the characteristic of sandy desertification land climate, distribution of Cyberspace and sandy vegetation types and distribution in Poyang Lake District, that ecological restoration of sand in Poyang Lake have accumulated certain amount of work in scientific research, demonstrate project and preferential policies, however there are some problem exist in exchanges and cooperation, protection and management, scientific guidance, etc. Those problems are major factors of limiting vegetation recovery. Pinus elliottii had been found as pioneer plant suitable for sandy land ecosystem reconstruction. It had been widely naturalized in sandy land owning to the feature of drought resistance, adapted to poor nutrients environment and the strong sand-fixing capacity. Through the analysis of the Bio-ecological Characteristics and biological adaptation for sandy land of P. elliottii, there are some problem exist in the risk of exotic species invasion, the harmful of single-species planting, the threat of plant disease and insect pest, the lack of mycorrhiza, etc. Those problems are major factors of limiting P. elliottii used in sandy land recovery. Based on this, The artificial water stress treatment was conducted with polyethylene glycol (PEG-6000) hypertonic solution, so that we can find the response of seeds of Pinus elliottii to water stress and drought-resistant mechanism. Adopt new techniques of vegetation restoration to establish demonstration zones. Make an investigation on the growth of P. elliottii, propose the restoration of sandy land vegetation measures. The results indicate that:(1)With water stress increased, P. elliottii seed germination rate, relative germination rate, germination potentiality, germination index, seedling shoot length and root length, biomass had a decreasing tendency in different degrees;(2)By established linear regression equation of seed germination under water stress, we can predict the drought tolerance critical value is-0.68MPa and limited value is-1.14MPa; When the concentration of PEG-6000 decrease to -0.8MPa, the P. elliottii seed can not sprout into seedlings, aimed to adapt to drought environment, under -1.07Mpa the biomass decreased to 0 directly;(3)The water stress had great impact on seed germination of P. elliottii early and will delay its germination time ranging from 1d-8d, respectively; The root of P. elliottii had a more stable growth under light water stress, showing adaptability to drought;(4)Through the analysis of field tests we can find soil water and nutrients were limiting factors of the P. elliottii growing on sandy soil. The P. elliottii one seedling age is not recommended to be planted on Poyang Lake sandy soil, because P. elliottii one seedling age showed that worse in resistance to adversity, only have the survival rates of 30%, the P. elliottii two seedling age can reach the survival rates of 80%. So plant P. elliottii two seedling age can get better performance on sandy soil.(5)The average height of the survive P. elliottii one seedling age were 32.8cm, 2 times higher than primary planted by investigation. whether P. elliottii can survive was a key problem about vegetation restoration of Poyang Lake sandy soil;(6)Raised concepts of construction of vegetation restoration demonstration: raising seedling around demonstration zone, not only we can study the growing dynamics of P. elliottii, but also can prompted P. elliottii to adapt the local environment, give a high survival rate and cut down expenses.(7)Comprehensively applying various vegetation restoration measures to establish demonstration of Duchang Xian so that the P. elliottii growing well and reflect the function of vegetation restoration. The average height of P. elliottii one seedling age can reach 70.8cm, the survival rates of 3500 per hectare. P. elliottii have development of feasibility and applicability on vegetation restoration of Poyang Lake sandy soil. |
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