凤仙花近缘种间核型分析与叶表皮微形态研究

为探究凤仙花近缘种植物的细胞学和微形态学方面的亲缘关系,该文选取荔波凤仙花(Impatiens liboensis)及近缘种赤水凤仙花(I.chishuiensis)和管茎凤仙花(I.tubulosa)的根尖和叶表皮为实验材料,采用体细胞染色体常规压片法和叶表皮光学显微镜观察法对凤仙花近缘种植物进行染色体及叶表皮特征研究。结果表明:(1)3种近缘种凤仙花核型均为2B。荔波凤仙花染色体数目为2n=16,核型公式为2n=2x=16=6m+4sm+2st+4T;赤水凤仙花染色体数目为2n=14,核型公式为2n=2x=14=12m+2sm;管茎凤仙花染色体数目为2n=14和2n=18,核型公式为2n=2x=14=4m+4sm+6T和2n=2x=18=4m+2sm+12T。(2)3种近缘种凤仙花叶表皮细胞均为不规则形,垂周壁式样有浅波状、波状两种;上表皮不具气孔器,下表皮均具气孔器;气孔指数和气孔密度差异大,可作为种间的分类依据。该文首次报道荔波凤仙花和赤水凤仙花的染色体数目、核型情况和叶表皮微形态特征。综上结果认为,凤仙花属植物的物种多样性可反映在高度可变的染色体数目和叶表皮形态上,染色体核型特征和叶表皮微形态特征对探讨凤仙花属种间亲缘关系、地理分布格局具有一定的科学意义,也可作为其分类的参考依据。

Research on karyotype analysis and leaf epidermal micromorphology of related species of Impatiens

Impatiens L.(Balsaminaceae)is a genus that contains ca. 1 000 species mainly distributed in tropical and subtropical regions of Asia and Africa. Several studies have been carried out within this genus, however, there is still paucity in the karyotype research. In order to explore the genetic relationship of cytological and micromorphological characters among related species of Impatiens, the chromosome and leaf epidermal characteristics of the genus were studied. Here, we report the chromosome analysis and leaf epidermal characteristics of three related Imaptiens species, I. liboensis, I. chishuiensis and I. tubulosa, using conventional squash method together with light microscopy observations. The results were as follows:(1)The karyotypes of all these three species were 2B. I. liboensis, the chromosome number was 2n=16, and the karyotype formula was 2n=2x=16=6m+4sm+2st+4T, whereas, for I. chishuiensis, the chromosome number was 2n=14, and the karyotype formula was 2n=2x=14=12m+2sm. Additionally, in I. tubulosa, the chromosome number was 2n=14 or 2n=18, and the karyotype formula was 2n=2x=14=4m+4sm+6T or 2n=2x=18=4m+2sm+12T.(2)In terms of leaf epidermal characteristics, the shape of epidermal cells for these species was irregular, with anticlinal walls sinuolate or sinuous; Stomata were only observed from the abaxial side; The stomatal index and stomatal density of the three species of Impatiens were quite different, and can be used for the taxonomy of these three Imaptiens species. The chromosome number, karyotype and leaf epidermal characteristics of I. liboensis and I. chishuiensis were reported for the first time. Therefore, the high species diversity in Impatiens is reflected in the hypervariable chromosome number and leaf epidermis, chromosome karyotype and leaf epidermal characteristics hence could be used to study the relationship and geographical distribution of the genus Impatiens and as important features for its taxonomy.