大叶相思染色体核型分析

A KARYOTYPE ANALYSIS ON ACACIA AURICULIFORMIS

研究大叶相思（Ａｃａｃｉａａｕｒｉｃｕｌｉｆｏｒｍｉｓ）的染色体数目及核型。大叶相思体细胞染色体数目为２ｎ＝２６，１０对（Ｎｏ．１，３～５，７，９～１３）为中部着丝点染色体，３对（Ｎｏ．２，６，８）为亚中部着丝点染色体，其中３对（Ｎｏ．１～３）染色体上具随体（Ｓａｔ），其核型组成为ｋ（２ｎ）＝２６＝２０ｍ（４Ｓａｔ）＋６Ｓｍ（２Ｓａｔ）。它的染色体长度比（最长／最短）为３．６２，臂比大于２的百分比为０．０７，属Ｓｔｅｂｂｉｎｓ的“２Ｂ”核型类型。

The karyotype and chromosome number of A cacia auricullformis，wereanalysed on meristematic cell of root tips．The resuIt showed that the chromosome numberin each somatic cell was 2n＝26．THe 10 pairs of chromosomes（No.1，3～5，7，9～13）were metacentric， and the 3 pairs of chromosomes（No. 2，6，8）were submetacen-tric. the lst through 3 rd of pairs（No.1～3）were SAT-chromosomes．According to theclassification made by Levan et al， the karyotype f ormula is k（2n）＝26＝20 m（4 Sat）＋6Sm（2Sat）. Accoding to the ration of chromosome length（length largest ／ smallest）and the pro-portion of chromosomes with arm ratio ＞ 2 in the complement，the karyotype of Acaciaauriculiformis belongs to Stebbins′“2B”of karyotype symmetry.