Aneuploidy and genetic differentiation in Carex pisiformis-complex (Cyperaceae)

豆状苔草复合体是苔草属中分类难度最大的类群之一。本研究的目的是修订分类方法，描述豆形苔草复合体的减数分裂染色体行为。为了评估类群间的遗传关系，对40个居群进行了同工酶分析。分类修订从北海道地区采集的标本与高山毛壳区别开来。互花草(法语)Ohwi通过短秆和浅带褐色的鞘。从日本西部采集的一个新分类群，从狭长且卷曲的叶片中很容易与华南华南和华南华南区分开来。通过对豆形藻复合体的形态研究，鉴定出豆形藻复合体15种11变种。细胞学观察对豆形弯孢霉复合体的7个分类群的减数分裂中期染色体数目和形态进行了测定。在5个分类群中观察到连续的染色体数目。减数分裂中期，三价体均为异形链构型。这些结果表明，非整倍体序列主要起源于染色体突变，随后通过自交或异花授粉在每个群体内保持非整倍体。利用聚丙烯酰胺凝胶电泳法对该复合体中的40个群体进行了检测，得到了10个酶系的13个可解释基因座。在4个分类群中发现了基因重复。邻接现象图表明，这4个类群通过染色体数目的增加聚在一起，由2n=56-61的祖先进化而来。

Carex pisiformis-complex is one of the most taxonomically difficult groups in the genus Carex. The aim of this study is to revise the taxonomic treatment and describe the meiotic chromosome behavior of Carex pisiformis-complex. To assess genetic relationships among taxa, 40 populations were used for isozyme analysis.1. Taxonomic revisionThe specimens collected from Hokkaido Prefecture, were distinguished from C. sachalinensis var. alterniflora (French.) Ohwi by short culm and pale brownish sheaths. A new taxon collected from western Japan was easily distinguished from C. fernaldiana and C. hakonemontanae by narrow and rolled leaves. Fifteen species and eleven varieties were recognized by morphological studies of C. pisiforms complex.2. Cytological observationChromosome number and configurations at meiotic metaphase were determined for seven taxa of C. pisiformis-complex. Consecutive chromosome numbers were observed in five taxa. At meiotic metaphase, every trivalent was heteromorphic chain configurations. These results indicate the aneuploid series originated primarily from chromosome mutation and, subsequently, maintained aneuploidy within each population by self/or cross-fertilization.3. Allozyme variationForty populations in the complex were examined utilizing polyacrylamide gel electrophoresis and thirteen interpretable loci were scored for ten enzyme system. Gene duplications were found in four taxa. Neighbor joining phenogram shows these four taxa are clustered together and derived from ancestors with 2n=56-61 through increasing in chromosome number.