国产8种蜘蛛抱蛋属植物的核型研究

Karyotypes of eight species of the genus Aspidistra from China

首次报道了 8种蜘蛛抱蛋属植物的核型 ,其中 6种的染色体数目为首次报道。结果如下 :峨边蜘蛛抱蛋A .ebianensis,2n =2x=36=1 8m +2sm(2sat) +1 6st;盈江蜘蛛抱蛋A .yingjiangensis,2n =2x =36=1 4m +6sm(2sat) +1 6st;海南蜘蛛抱蛋A .hainanensis,2n =2x =36=2 0m(2sat) +1 4st+2t;石山蜘蛛抱蛋A .saxicola,2n =2x =36=1 6m +4sm(2sat) +1 6st;糙果蜘蛛抱蛋A .muricata ,2n =2x =36=1 8m +2sm(2sat) +1 6st;啮边蜘蛛抱蛋A .marginella ,2n =2x =38=2 2m +4sm(2sat) +1 2st;西林蜘蛛抱蛋A .xili nensis,2n =4x=76=48m(4sat) +2sm +2 6st;十字蜘蛛抱蛋A .cruciformis,2n =4x =76=46m(4sat) +1 2sm+1 8st。核型类型都为 2C型。首次在中国发现了A .cruciformis和A .xilinensis的野生四倍体。根据外部形态性状及已有的 38种植物的核型资料分析 ,认为该属染色体的原始基数可能为x =1 8,核型向对称性增强的方向演化 ,其主要表现在中部着丝粒染色体数目的增多 。

This paper reports the chromosome number and morphology of 8 species of the genus Aspidistra from China. The chromosome number of six species is reported for the first time.The results are as follows: 2n=2x=36=18m+2sm(2sat)+16st for A. ebianensis ; 2n=2x=36=14m+6sm(2sat)+16st for A. yingjiangensis ; 2n=2x=36=20m(2sat)+14st+2t for A. hainanensis ; 2n=2x=36=16m+4sm(2sat)+16st for A. saxicola ; 2n=2x=36=18m+2sm(2sat)+16st for A. muricata ; 2n=2x=38=22m+4sm(2sat)+12st for A. marginella ; 2n=4x=76=48m(4sat)+2sm+26st for A. xilinensis ; 2n=4x=76=46m(4sat)+12sm+18st for A. cruciformis . All the karyotypes are bimodal and belong to Stebbins' 2C type. A. cruciformis and A. xilinensis are the only two tetraploid species found in Aspidistra up to date. Based on our results and those previously reported,we consider that the karyotypes of the genus Aspidistra might have evolved towards the increase of symmetry by the increase of median_centromeric chromosomes in the chromosome complement and the basic chromosome number x=18 might be primitive, while x=19 derived.