狗牙花叶的结构特征及生态意义

LEAF ANATOMIC STRUCTURE OF ERVATAMIA DIVARICATA AND ITS ECOLOGICAL SIGNIFICANCE

采用冷冻切片法,在光学显微镜下观察研究了狗牙花叶的解剖结构。结果表明:狗牙花叶为典型的异面叶,但同时具有某些阳生(旱生)叶和阴生叶的特点。表皮由一层排列紧密的细胞组成,细胞外壁具角质膜,气孔主要分布在下表皮,上表皮仅有零星分布,气孔器类型为平列型;叶肉组织发达,叶肉细胞常含有晶体,栅栏组织由1-2层排列整齐的圆柱状细胞组成,海绵组织交织成网状,有大的细胞间隙,横切面上栅栏组织与海绵组织厚度之比为0.32:1;中脉维管组织较发达,为周韧维管束。以上特征反映出狗牙花叶结构特点与其生长环境的统一性。

The leaf anatomical structure of Ervatamia divaricata（L.） Burk.cv.Gouyahua was studied by cryosectioning method and optics microscope.The results indicate that the leaves are typical bifacial leaf and display some characteristics of sun leaf（dry leaf） and shade leaf in the morphology and the anatomy.Each epidermis consists of one layer of epidermic cells closely arranged which have cuticle on the ektexine.The stomata exist mainly in lower epidermis,only a few stomata exist in upper epidermis,and the stomata apparatuses are paracytic type.The mesophyll tissue is very rich and contains crystals,the palisade tissue is composed of 1-2 layers of cylindrical cells,the spongy tissue interweaves to form reticular formation and the intercellular space is developed.The ratio of the palisade tissue to the spongy tissue is 0.32：1.The vascular bundle of midrib is the amphicribral vascular bundle which is rather developed.All these characteristics indicate that the plant＇s leaf structure is well adapted to its growing environment.