水鳖科3种海草的染色体及其核型的研究

目的]对采自海南黎安港的3种水鳖科海草———海菖蒲(Enhalus acoroides)、泰来藻(Thalassia hemprichii)和小喜盐草(Halophilaminor)的染色体及其核型进行研究。方法]采用海菖蒲和泰来藻的根尖及小喜盐草的腋芽为材料,采用常规压片法制备染色体玻片标本,并对其进行核型分析。结果]海菖蒲和泰来藻的染色体数目为2n=18,小喜盐草的染色体数目为2n=28,两者均未发现B染色体和随体;海菖蒲、泰来藻和小喜盐草的核型公式分别为K(2n)=18=12m+6sm,K(2n)=18=12m+6sm,K(2n)=28=16m+8sm+4st;按Stebbins的核型分类标准,海菖蒲和泰来藻的染色体属2A类型,小喜盐草为2B型。结论]通过对3种海草核型进行比较发现,海菖蒲与泰来藻的核型差距很小,而它们与小喜盐草的核型差距较大,说明海菖蒲与泰来藻的亲缘关系更近。

Chromosomes and Karyotypes of Three Seagrass Species of Hydrocharitaceae

Objective] This study aimed to study the chromosomes and karyotypes of 3 seagrass species of hydrocharitaceae—Enhalus acoroides,Thalassia hemprichii and Halophila minor collected from Li’an Lagoon,Hainan Province,China.Method] The root-tips of E.acoroides,T.hemprichii and the axillary buds of H.minor were selected as the materials in this study.The conventional crushing method was used to prepare the slice specimens of chromosomes,and the karyotypes of the 3 species were analyzed.Result] The chromosome numbers of E.acoroides,T.hemprichii and H.minor were 2n=18,18,28,respectively.The karyotype formulas were K(2n)=18=12m+6sm,K(2n)=18=12m+6sm and K(2n)=28=16m+8sm+4st,respectively.According to the standard of Stebbins,the karyotypes of E.acoroides and T.hemprichii were 2A,and that of H.minor was 2B.There is no B chromosome and satellite in the 2 species.Conclusion] According to the comparison on the karyotypes of these 3 species,E.acoroides and T.hemprichii are similar in karyotypes to each other,indicating that the inter-relationship between E.acoroides and T.hemprichii is closer.