Study On Salt Tolerance Of Main Afforestation Tree Species In North Of The Taklimakan Desert

In this paper, we get proper salt water drip irrigation amount of some main afforestation tree species under salt stress, and evalue salt torlerance of some main afforestation tree species by some commom physiology indexes, which can provide the theory basis and the technology support for the establishment of the oases protective system in the saline land in arid , semi-arid area where freshwater resources are gradually short- supplied. Besides, and further know about salt mechanism of plant and provides the theory basis for recovery of degeneration vegetation and development of ecological industry in arid area, and also increase kinds of salt plant at the same time, which have important practical significance to improve the local partal ecological environment, maintain biodiversity and improve salinized soil, by the salt water drip irrigation amount study, shelter belt study and natural Populus euphratica mixed Community study in Yuli, xinjiang, the main conclusion of the entirele study as follows:(1) In the study that salt water irrigation amount of different plants by drip irrigation, we try to find the appropriate amount of salt water drip irrigation for five different plants by determining their growth of main morphological indexes in different levels of salt water irrigation amount (3000, 4500, 6000 m³Â·hm^-2 every year) at nursery in Yuli, Xinjiang , including height, ground diameter, crown width and total dry biomass. The results showed that the suitable salt water drip irrigation for Populus×xiaozhuanica"Zhongtian"and A. canescen is 4500 m³Â·hm^-2, and that of Tamarix ramosissima, Populus alba×Populus albavar var. pyramidal and Populus euphratica Oliv.is 6000 m³Â·hm^-2. At surface (0⁵ cm), soil water content was lowest and soil salt content was highest, and with the depth of soil, soil water content is more, buts oil salt content is less. When the depths of soil exceed 10 cm, the soil water and salt content did not change significantly.(2) In the preliminary study about salt tolerance of three Populus plants at seedling stage in shelter belt in north of Yuli, Xinjiang, five physiology indexes, that is leaf proline content, K⁺/Na⁺, Cl^-, SOD, MDA, were chosen to evaluate comprehensively salt tolerance of three Populus plants at seedling stage by hierarchical cluster and subordinate function, the results showed that salt tolerance of Populus alba L.var.pyramidalis was highest among Populus alba L.var.pyramidalis, Populus euphratica Oliv. and Populus alba×Populus alba var. pyramidalis Bunge., and salt tolerance of P. euphratica was similar to that of P. alba×P. alba var. pyramidalis Bunge. Otherwise, we could find that leafδ¹³C value was low when the salt tolerance was high for three Poplus trees.(3) In the study about salt tolerance of Populus euphratica Oliv. and Tamarix spp., we chose five physiology indexes, that is leaf proline content, K⁺/Na⁺, Cl^-, SOD, MDA, to evaluate comprehensively salt tolerance of P. euphratica and Tamarix spp. in natural Populus euphratica mixed community in Yuli by subordinate function, the preliminary conclusion is that the salt torlerance of P. euphratica is similar to that of Tamarix spp., and the first is higher.