多辐溲疏居群过氧化物酶同工酶分化的研究

Numerical analysis of peroxidase isozymic differentiation within and among populations of Deutzia multiradiata

运用聚丙烯酰胺凝胶电泳，测试了采自四川南川县金佛山不同生境的多辐溲疏５个居群５０株个体的过氧化物酶同工酶，对酶谱带位置进行了二态编码，然后采用Ｒｏｇｅｒｓ－Ｔａｎｉｍｏｔｏ，Ｓｏｋａｌ－Ｍｉｃｈ－ｅｎｅｒ，Ｓｏｋａｌ－Ｓｎｅａｔｈ，Ｊａｃｃａｒｄ等结合系数用组平均法（ＵＰＧＭＡ）对各谱带位置进行了聚类分析．结果表明，相同生境同一居群内的个体间表现出较大的遗传同质性，而来源于不同生境的不同居群个体间却呈现出较大的遗传趋异性；同时，５个居群不但具有许多共同谱带，而且整体相聚的结合系数大多超过０．５，这表明５个居群在很早以前可能是属于同一大居群，在长期进化过程中，由于微生境的地理与气候因子选择，使得多辐溲疏现仅在金佛山海拔６００～１２００ｍ的约ｋｍ２范围内呈岛状分布；又由于其特殊的繁殖方式——居群内个体虽能杂交，但因该种仅能正常开花传粉，大部分种子败育，使得居群内个体遗传变异性不能通过有性生殖方式固定下来，仅能通过营养繁殖方式繁殖后代，而正是营养繁殖导致了居群内较大遗传同质性以及居群间的遗传趋异性．

The peroxidase(PER) isozymic variation in leaves of 50 plants of Deutzia multiradiata collected from 5 small populations with different altitudes and habitats in Mt.Jinfo of Nanchuan,China is studied with the electrophoretis technique.The isozyme bands of the peroxidase are scored to construct the two state data matrix which is calculated by Rogers Tanimoto,Sokal Michener,Sokal Sneath and Jaccard association coefficients clustered by UPGMA respectively.Results indicate that individuals from the same population do show higher genetic homogeneity,while individuals from different populations posse rather high genetic dissimilarities.Some PER bands are permanent to all individuals of 5 populations.The isozymic association coefficients(association coefficients) between populations are mostly larger than 0 5,which indicate that those 5 small populations may come from a big population formed long ago and the selection pressure from environment during the long history of evolution makes Deutzia multiradita distribute as scattered,spatially isolated small populations endemic to Mt.Jinfo.Such spatial isolation largely inhabits the gene exchange among individuals from different micro populations and those adapted genetic variations to those micro habitats are selected and remained in the evolutionary process,which makes the genetic divergence on PER among micro populations becoming more obvious.The microhabitats here only play the role in selecting that habitat.The vegetative reproduction of the species lead to the obvious genetic homogeneity among individuals from the same population.