| With the present broadly applied high-quality triploid Chinese white poplar for afforestation, pulp and construction as data, this paper explores systematically factors affecting the breeding and extensive reproduction system in poplar tissues and establishes fast high-frequency regeneration system of triploid Chinese white poplar. The research employs cultivation and dissemination of Agrobacterium tumefaciens to establish high-efficiency heredity conversion system. It leads Anti-PLDy in the system for the expression of the gene and acquires salt-resisting transgenosis plant. Concrete operations are as follows:1. Establish High-frequency Regeneration System of Triploid Chinese White PoplarSelect the third to fifth blades of the plant to cut the surface and then induces them on MS medium to produce callus. Indicated by the analysis of the breeding conditions of the tissue, proper hormone potency and proportioning are the key to acquisiton of high-efficiency regeneration system and appropriate physico-chemical conditions are of importance to regeneration, subculture and extensive reproduction of the plant as well. Apply such factors as hormone potency and proportioning, agar potency, dark disposal in orthogonal test. Take root-striking rate, sprouting rate, plant height and blade number as detection index to find out the high-efficiency regeneration conditions. Result shows: Callus of the plant's blade of water planting, when led in MS induction medium for sprout differentiation, can reach sprouting rate of over 90%; transfer regenerated sprout into grown sprout medium to accelerate its growth, then within two weeks or so the sprout can grow to 5-7cm; at this point transfer the plant into root-striking medium, in 7-10 days root-striking rate can reach 90-100%. Dark disposal at initial stage does not have much effect on regeneration frequency of the plant.2. Establish High-efficiency Heredity Conversion System of Chinese White Poplar On the basis of establishment of poplar blade callus high-frequency regenerationsystem, carry on the study of poplar heredity conversion, mediated and induced by Agro-bacteriunm tumefaciens. Many factors as optimum conversion state, kan selection pressure, heredity conversion method, disposal period and screening method are all in this study. As indicated, proper activation of Agrobacterium tumefaciens with PLI>y- 4 9 -before conversion, application of bacterium liquid diluted by surface active agent of certain potency in addition to the use of 15% sucrose, overnight stay on filter paper of blade disseminated by Agrobacterium tumefaciens with no washing, and following replacement of regeneration medium with filter paper soaked by regeneration liquid medium can improve conversion frequency in an effective way.3. Qualify Hereditary Value of Transgenosis PlantWith unconversed plant as negative tester and plasmid promoter and part of the sequence in Anti-PLDy as model plate to synthetise specific primer, checked by PCR. Result shows: Extended strip in transgenosis plant agrees with target strip in plasmid while no strip extended in unconversed plant; this indicates PLDy of external source Further PCR-Southem test also tells extension of external source gene is thue to believe.4. Test Salt Tolerance of Transgenosis PlantReplace resistance conversion plant to MS medium added with 0.3-1% NaCI and have salt-resistance screening, unconversed plant as tester. Findings tell: Affer successiver subscreening in 3 months, with the increase of screetng potency, yellowing rate of the plant rises while that of conversion plant drops noticeably in comparison with unconcersed one. This shows the salt toberance of transgenosis plant improves in distinct degree. Hence the thesis-Gene PLD can change physiological function of a plant in the way of affecting its signal transfer system-is verified.
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