摘要： 基于体细胞染色体核型及花序特征对菝葜科Smilacaceae菝葜属Smilax和肖菝葜属Heterosmilax进行了系统演化研究, 报道了国产菝葜科17个分类群的核型。根据已研究的部分形态学特征和已有的分子序列资料, 对它们的系统进化进行了分析。结果显示: (1)整个类群的核型变异表现在二型化、多倍化、染色体的微变异以及染色体基数递减(从16–15–13), 16为菝葜类群的基本染色体基数。(2)草本菝葜的核型对称性在东亚到北美种类中, 表现出从对称到不对称的变化, 而木本菝葜的各组间并未表现出这种趋势。(3)先出叶Smilax. The karyotypes and chromosomes of 17 taxa of Smilax and Heterosmilax were examined and compared with previous studies of Smilacaceae. Phylogeny and karyotype evolution of the two genera are discussed in this paper along with evolutionary trends in inflorescence morphology, in the context of gene trees based on nrDNA ITS sequences. Karyotypes of these 17 taxa are characterized as follows: (1) “woody S. riparia”, 2n=32=L(2m+2st+2t)+M(4sm+4st)+S(2m+8sm+8st); (2) S. scobinicaulis, from Guizhou, 2n=32=L(2sm+4st+2t)+M(6sm(SAT)+2st)+S(2m+6sm+8st); (3) S. china in Shennongjia, Hubei is a diploid, 2n=32=L(6st)+M(4sm+6st)+S(2m+6sm+8st); (4) S. china in Guangxi with 4x, 2n=64=L(2sm+12st+2t)+M(4sm+8st)+S(6m+20sm+10st); (5) S. china from Japan with 4x chromosomes, 2n=64=L(4sm+14st+2t)+M(6st)+S(4m+28sm+6st); (6) S. trinervula from Guiyang, 2n=32=L(8st)+M(2sm+2st)+S(2m+6sm+12st); (7) S. chingii, 2n=32=L(2sm +6st)+M(4sm+4st)+S(2m+10sm+4st); (8) S. ferox from Kunming, a hexaploid, 2n=96= L(6sm+22st+6t)+M(2sm+10st)+S(6m+28sm+16st); (9) S. lebrunii from Sichuan, a hexaploid, 2n=96=L(4sm+24st)+M(4sm+10st)+S(10m+26sm+18st); (10) S. stans from Chongqing, 2n=32=L(4st+2t)+M(2sm+4st)+S(12sm+8st); (11) S. austro-zhejiangensis found in Zhejiang, 2n=32=L(4st+2t)+M(2sm+6st)+S(12sm+6st); (12) S. umbrosa found in Mt. Emei, 2n=32= L(2sm+6st)+M(2m+2sm+2st)+S(4m+8sm+6s); (13) S. bockii from Mt. Jingfo, 2n=32= L(2sm+6st)+M(6st+2m)+S(8sm+8st); (14) S. guiyangensis from Guiyang, 2n=32=L(6sm+ 2st)+M(4sm+2st)+S(2m+10sm+6st); (15) S. vanchingshanensis from Guizhou, 2n=32 =L(2sm+6st+2t)+M(4st)+S(4m+6sm+8st); (16) S. lunglingensis from Kunming, 2n=32= L(4st)+M(4sm+4st)+S(6m+6sm+6st); and (17) S. polycephala from Yunnan, 2n=32= L(2sm+ 6st)+M(2sm+6st)+S(6m+6sm+4st). The results showed that the karyotypes of Smilax and Heterosmilax are bimodal, with evidence of polyploidization, micro-variation, and variance of basic number from 16 to 15 and 13. We suggest that the karyotypes of the herbaceous Smilax species show a trend from symmetry in East Asian taxa to asymmetry in North America, but no such trend is obvious among woody species.
| ┌---L--┐ ┌----M---┐ ┌----S---┐ |
Regarding the inflorescence, we consider the prophyll to be a persistent bract. Therefore, the branches composed of single umbels borne in axils and with a prophyll at the base of the entire branch (i.e., sect.
China and sect.
Coilanthus) are homologous with the inflorescences possessing a prophyll at their base, or with a node on the peduncle and only a single umbel (in sect.
Macranthae and sect.
Smilax). Based on this interpretation and previous published ITS sequences, it is evident that a spike of umbels lacking peduncles is the primitive type of inflorescence in Smilacaceae from which two types of inflorescences are derived: (1) a solitary umbel without a prophyll, including species within
Heterosmilax and
Smilax section
China and
Coilanthus; and (2) a panicle-like type with one to many umbels subtended by a prophyll, i.e., the species of
Smilax sect
. Macranthae. Furthermore, our data suggest that
Heterosmilax should not be recognized as a separate genus, but as a subgenus closely related to species of the herbaceous section of
Smilax and
Smilax sect.
Coilanthus. The herbaceous species of
Smilax, originating in East Asia and then expanding into North America, form a monophyletic group and a common ancestry with sect.
Coilanthus. They are recognized as
Smilax sect.
Nemexia. Finally, studies of
S. china show that it is a widespread species with varying ploidy levels. In this paper, a diploid population has been documented from Hubei, suggesting that tetraploid populations were widely distributed in East
孔航辉, 王艾丽, 李重求, 傅承新. 菝葜属和肖菝葜属的核型变异和系统演化研究[J]. 植物分类学报, 2007, 45(3): 257-273.
KONG Hang-Hui, WANG Ai-Li, LEE Joongku, FU Cheng-Xin. Studies of systematic evolution and karyotypic variation in Smilax and Heterosmilax (Smilacaceae)[J]. Acta Phytotaxonomica Sinica, 2007, 45(3): 257-273.
