孝昌马尾松天然林同工酶遗传构造的分析研究

Study on genetic Structure of natural population of Masson Pine in Xiaochang country Hubei province by Isozyme technique

摘要:

通过对湖北省孝昌县小悟乡的马尾松（Ｐｈｕｓ ｍａｓｓｏｎｉａｎａ）天然林的针叶进行的同工 酶实验，６种酶系统的１１个基因位点得到了确认。以各基因位点上的等位基因的频率为基础， 对该林分内部的遗传变异进行了研究，结果表明，该林分具有较高的遗传变异性，其多态位点 百分率（ＰＩ）为９０．９％、等位基因平均数（Ｎａ）为３．１８、有效等位基因（Ｎｅ）为１．９１、平均期待杂 合率（Ｈｅ）为０．４２、近交系数（Ｆｉｓ）为０．３３，且存在不同基因位点间高频率的连锁不平衡。同时 将马尾松个体间的距离分成不同的等级，考察各等位基因频率的变化情况（Ｍｏｒａｎ’ｓＩ和ＳＮＤ 曲线的变化规律），进一步对该林分内的遗传构造和林分的成立过程进行了研究和探讨，发现 其邻域的大小为１０～１２ｍ。在此基础上提出了对该类的天然林的遗传资源保存的对策。

Abstract:

Genetic structure of a Masson Pine natural forest in Xiao Wu countryside,Xiaochang country, Hubei province was studied using 11 isozyme loci,encoding sixenzyme systems,and inferred the establishment processes of the stand. Results indicated htat the studied stand possessed a fairly high level of genetic variation: the proportion of polymorphis loci (Pl) = 90. 9%, average number of alleies per locus (Na)= 3. 18, effective number of alleies per locus (Ne) =1. 91,and average expected heterozygosity (He)= 0. 42. Patchy genetic structure was found in the stand,and neighbourhood size was estimated ot be 10-12 m. The stand retained a high degree of inbreeding (Fis= 0. 33). Moreover, statistically highly significant linkage disequilibria were found in amny locus pairs. Strategieds for protecting the Masson Pine natural forest and for conserving genetic resources were discussed.