Study On Major Characters And The Origin Of Pinus Densiflora Var. Zhangwuensis

This paper focuses on physiological characters and origin of Pinus densiflora Var. zhangwuensis using traditional genetic breeding techniques and molecular marker methods (RAPD and SSR). Determination of physiological indices shows that water contents in tender leaves of the tree is range from 53.3% to 73.3%, in which free water is 37.5% to 67.7% and bound water is 5.6% to 15.8%, and the ratio of both is 12.09 to 2.37. The daily evaporation rate of the plant changed remarkable in each season, in June and Aug., it is doublet while in Oct. it is singlet, the maximum value of evaporation rate appears in July and its tendency in the whole year is singlet. Comparing to f'imis sylvestris var. mongolica in similar environment, trees of Pinus densiflora Var. zhangwuensis own 1.53 times of chlorophyll than that in f'imis sylvestris var. mongolica, meanwhile, they have not only lower evaporation intensity and rate of water loss, but also higher water and organic materials storage. Using random-amplified poly-morphic DNA (RAPD) and microsatellite DNA (SSR) methods, possible origin of Pinus densiflora Var. zhang\vuensis was analyzed. Fingerprint of Pinus densiflora Var. zhangw'iiensis shows specific features varying with other species such as f'inns densiflora, Pinus tahiilaeformis and Pinus. sylvestris var. mongolica. In clustering map of RAPD, distance from Pinus densiflora Var. zhang\viiensis and Pinus densiflom is nearer than Pinus labiilaeformis and Pinus sylvestris var. mongolica. This leads to speculation that Pinus densiflora Var. zhangwuensis is probably the variant of Pinus densiflora or hybrid of Pinus densiflora and Pinus tabulaeformis. The genetic distance among three species implies that Pinus densiflora makes higher contribution to the hybrid. SSR analysis shows that Pinus densiflora Var. zhangwuensis maybe is the hybrid of Pinus tabulaeformis . The paper also studies the major hereditary character of Fl generation of Pinus densiflora Var. zhangwuensis. Segregation characters such as growth potential, needle length and color, appears in Fl, but most plants of Fl was in middle type Phenotypes of segregation characters, such as needle length, plant height, basal diameter, are in normal distribution, which indicates that they are controlled polygenetic. These four quantity characters varies greatly, the needle length ranges from 65 mm to 15mm, the plant height is from 100mm to 32mm and extremum of basal diameter is from 3.7mm to 1.0mm. Color of Fl plants segregates into four types, including violet, green, violet with green andgreen with violet. According to characters of Fl plants, origin of Pinus densiflora Var. zhangwuensis can be referred to. Based on this study, temporary conclusion is drawn that Pinus densiflora Var. zhangwuensis is originates from natural hybridization of Pinus densiflora and Pinus tabulateformis.