中国假鹰爪属和皂帽花属植物叶的形态结构及其分类学意义

Leaf anatomy of Desmos and Dasymaschalon (Annonaceae) from China in relation to taxonomic significance

利用扫描电镜技术、叶片离析法和石蜡切片法研究了假鹰爪属Desmos4种植物和皂帽花属Dasy maschalon 3种植物叶片的形态结构。结果表明 :假鹰爪属植物叶片近轴面表皮具大型球状含晶簇细胞和不含晶簇的表皮细胞两种类型 ,远轴面表皮细胞均具一较小的晶簇 ;叶肉组织明显分化为栅栏组织细胞和海绵组织细胞 ,油细胞分布于第 2层的栅栏组织和海绵组织内 ,单位毫米叶宽油细胞数为 4～ 6个 ;主脉维管组织被薄壁细胞分隔成束状。皂帽花属植物叶片近轴面表皮细胞形状相同 ,均具一晶簇 ,远轴面表皮细胞的晶簇和近轴面表皮细胞的晶簇相似 ;靠近上、下表皮的叶肉组织均分化为栅栏组织细胞 ,在两层栅栏组织细胞之间分化为一至几层海绵组织细胞 ,油细胞分布于海绵组织内 ,单位毫米叶宽油细胞数为 2～ 3个 ;主脉维管组织形成连续的环状。由此可见两属叶的结构具有明显的差异 ,因而支持假鹰爪属和皂帽花属为两个独立属的观点。

Leaf morphology in four species of Desmos and three species of Dasymaschalon was comparatively studied using scanning electron microscopy (SEM) together with epidermal maceration and paraffin methods. The results showed that there were some remarkable foliar anatomical differences between Desmos and Dasymaschalon . In leaves of Desmos , some of the adaxial epidermal cells were enlarged into globose cells each containing one large cluster crystal, while other epidermal cells were normal without any crystal, and in abaxial epidermis each cell contained one smaller cluster crystal. The leaf structure was typically bifacial, and the mesophyll cells were differentiated into palisade tissue and spongy tissue. Oil cells were distributed in the second layer of palisade and the whole spongy tissue, and the number of oil cells per mm leaf width ranged from 4 to 6. The vascular tissue in the midrib was separated into bundles by parenchyma cells. In leaves of Dasymaschalon, all the adaxial epidermal cells contained one cluster crystal, and the crystal size was similar to that of the crystals in abaxial epidermal cells. The leaf structure was more or less isobilateral. Oil cells were distributed only in the spongy tissue between the two layers of the palisade, and the number of oil cells per mm leaf width ranged from 2 to 3. The vascular tissue in the midrib formed a continuous circle. It is clear that the anatomical differences between Desmos and Dasymaschalon are remarkable, supporting the treatment of Desmos and Dasymaschalon as two independent genera.