中国石灰岩专性凤仙花叶表皮特征及其分类学意义

Characters of leaf epidermis and their taxonomic significance in Impatiens(Balsaminaceae)obligated to limestone region from China

通过光学显微镜和扫描电镜技术对中国产的8种凤仙花科植物叶表皮微形态特征进行了实验研究,其中6种产于石灰岩地区,另外2种作为对照。结果表明,中国石灰岩地区的6种凤仙花的叶表皮微形态上、下表皮差异明显,上表皮细胞为不规则形和多边形,一般不具气孔器;下表皮细胞均为不规则形,均具气孔器,气孔器多为不等型。上、下表皮细胞形状、垂周壁式样、气孔器及其类型、气孔密度、气孔指数及气孔长宽比等性状均可作为分类学的佐证。前人研究中提及气孔的保卫细胞两极具"T"型加厚这一性状不稳定,不应作为分类处理的证据。

Characters of leaf epidermis of 6 Impatiens（BalsamJnaceae）from South China which are endemic to limestone region,and another 2 species Hydrocera triflora and I. davidii distributed beyond limestone region for con- trol, were examined by light microscopes（LM）and scanning electron microscope（SEM）. The result showed that there were large differences between the upper epidermis and lower ones in the mieromorphological characters, for example, cell shapes were irregular to polygon and without stomata except Hydrocera in upper epidermis vs. cell shapes were all irregular and with stomata in lower epidermis. The characters of cell shape, anticlinal wall, stomatal type, stomatal index（SI）, stomatal density（SD）either from upper epidermis or from lower ones were valuable in classification in Balsaminaceae. The characters of T-thickening at the polar region of guard cells and ornamentation of leaf epidermis mentioned formerly were with limited valuable in taxonomy.