Abstract: The present paper deals with the karyotypes of Pinus yunnanensis Franch. and P. kesiya var. langbianensis (A.Chev.) Gaussen. The chromosomes of them are 2n=24, which all belong to metacentric one. There are three pairs of chromosomes (No. 2, 5, 8) with secondary constriction in P. yunnanensis Franch., and only one (No. 3) in P.kesiya var. langbianensis (A. Chev.) Gaussen and its first pair of chromosomes are heterozygous. The karyotype of P.kesiya var. langbianensis (A. Chev.) Gaussen is not as regular as that of P. yunnanensis Franch. By the comparison between their karyotypes, it is shown that the relationship between both of them is not close and P. kesiya var. langbianensis (A. chev) Gaussen is more advanced than P. yunnanensis Franch. in the evolution.

Key words: karyotype, pinus, Yunnanensis

摘要： 本文研究了云南松Pinus yunnanensis Franch.和思茅松Pinus Resiya var.angbianensis(A.Chev.)Gaussen的染色体组型.二者的染色体数目为2n＝24,均由具中部着系点染色体所组成.但云南松有3对染色体具有次缢痕;而思茅松仅有二对染色体具有次缢痕,而且第一对染色体是杂合的.此外,思茅松的染色体组型较云南松更为不整齐.染色体组型比较的结果表明,二者的亲缘关系疏远,思茅松是比云南松更为进化的类型。

关键词: 云南松, 思茅松, 染色体组