The authors investigated the genetic diversity of 29 natural populations representing Pinus yunnanensis Franch. and its two close relatives, P. densata Mast. and P. kesiya Royle ex Gordn. var. langbianensis (A Chey.) ...The authors investigated the genetic diversity of 29 natural populations representing Pinus yunnanensis Franch. and its two close relatives, P. densata Mast. and P. kesiya Royle ex Gordn. var. langbianensis (A Chey.) Gaussen. Horizontal starch gel electrophoresis was performed for macrogametophytes collected from populations in Yunnan, Sichuan and Guangxi. Allozyme data for 33 loci of 14 enzymes demonstrated high levels of genetic variation at both population and species levels in comparison with other conifers, with the mean values for populations being P=0.694, A =2.0 and He =0.145 for P. yunnanensis; P=0.714, A=2.0 and He =0.174 for P. densata ; and P=0.758, A=2.1 and He =0.184 for P. kesiya var. langbianensis. Based on Wright’s F _statistics, the fixation index of P. yunnanensis, P. densata and P. kesiya var. langbianensis were 0.101, 0.054 and 0.143, respectively, indicating that the populations were largely under random mating. Based on Nei’s genetic distance, the genetic differentiation was not obvious among the three species (i.e. the genetic distance was less than 0.075). Because of the wider distribution of P. yunnanensis with greater variety of habitats, it was shown that the genetic differentiation among the P. yunnanensis populations was larger than that of the populations of the other two species. According to morphological, geographic and allozymic evidences, the authors suggested that the three species be better treated as varieties under a single species. In addition, the extensive gene flow among the three pine species resulted in great genetic diversity and evolutionary potential. Also, high level of genetic variation of P. yunnanensis provides important basis for its genetic improvement and breeding in future.展开更多
Based on analyses of the natural characteristics and exploitation advantageous conditions of Bita lake reserve, this paper recommended that the goal of scientific exploration tour was considered as a core program of e...Based on analyses of the natural characteristics and exploitation advantageous conditions of Bita lake reserve, this paper recommended that the goal of scientific exploration tour was considered as a core program of ecotourism. The concrete exploitation plans, including science interpretation, tourism items, signs explanation systems, guide training and guidebook establishment, were suggested. In addition, how to implement the plan and solve some problems that would be encountered were discussed in the article.展开更多
文摘The authors investigated the genetic diversity of 29 natural populations representing Pinus yunnanensis Franch. and its two close relatives, P. densata Mast. and P. kesiya Royle ex Gordn. var. langbianensis (A Chey.) Gaussen. Horizontal starch gel electrophoresis was performed for macrogametophytes collected from populations in Yunnan, Sichuan and Guangxi. Allozyme data for 33 loci of 14 enzymes demonstrated high levels of genetic variation at both population and species levels in comparison with other conifers, with the mean values for populations being P=0.694, A =2.0 and He =0.145 for P. yunnanensis; P=0.714, A=2.0 and He =0.174 for P. densata ; and P=0.758, A=2.1 and He =0.184 for P. kesiya var. langbianensis. Based on Wright’s F _statistics, the fixation index of P. yunnanensis, P. densata and P. kesiya var. langbianensis were 0.101, 0.054 and 0.143, respectively, indicating that the populations were largely under random mating. Based on Nei’s genetic distance, the genetic differentiation was not obvious among the three species (i.e. the genetic distance was less than 0.075). Because of the wider distribution of P. yunnanensis with greater variety of habitats, it was shown that the genetic differentiation among the P. yunnanensis populations was larger than that of the populations of the other two species. According to morphological, geographic and allozymic evidences, the authors suggested that the three species be better treated as varieties under a single species. In addition, the extensive gene flow among the three pine species resulted in great genetic diversity and evolutionary potential. Also, high level of genetic variation of P. yunnanensis provides important basis for its genetic improvement and breeding in future.
文摘Based on analyses of the natural characteristics and exploitation advantageous conditions of Bita lake reserve, this paper recommended that the goal of scientific exploration tour was considered as a core program of ecotourism. The concrete exploitation plans, including science interpretation, tourism items, signs explanation systems, guide training and guidebook establishment, were suggested. In addition, how to implement the plan and solve some problems that would be encountered were discussed in the article.
