闽楠营养器官的解剖结构及其生态适应性

Anatomical structures of the vegetative organs of Phoebe bournei( Hemsl.) Yang and ecological adaptability

采用石蜡切片和光学显微技术对闽楠(Phoebe bournei(Hemsl.)Yang)营养器官的解剖结构及其生态适应性进行了研究。结果显示,闽楠为典型异面叶,叶片中脉发达,维管束呈扇形,导管径向排列,韧皮部外侧有大量韧皮纤维分布。上表皮外侧具角质层,下表皮外侧无角质层,下表皮细胞呈犬牙状向外凸起,有表皮毛和气孔分布,气孔为双环型、外凸;栅栏组织由1层细胞组成,海绵组织由3~4层细胞组成。茎的初生结构中,表皮轻微角质化,厚角细胞5~6层,薄壁细胞5~7层,维管束为外韧型;茎的次生结构中,表皮外部角质层加厚,木栓层细胞3~4层,木栓形成层细胞1层,栓内层细胞2~3层,维管束紧密排列连成环状,次生韧皮部和次生木质部发达,形成层细胞2~3层。根的次生结构中木栓层细胞5~6层,木栓层内侧具1层木栓形成层,栓内层细胞2层。闽楠营养器官的解剖结构特征一方面呈现出阴生植物的特点,另一方面也对阳生和旱生环境具有一定的适应性。

The anatomy features of the vegetative organs of Phoebe bournei（ Hemsl.） Yang were studied by paraffin-sectioning and optical microscopy to explore ecological habitat adaptability. Results showed that P. bournei had a typical bifacial leaf with well-developed midvein,vascular bundles were fan-shaped,and the vessels were arranged radially. A large number of phloem fibers were distributed outside the phloem. A cuticle existed on the outside of the upper epidermis of the leaf. The lower epidermis cells were outward and showed a zigzag shape,and there were epidermal hairs and stomata on the surface of the lower epidermis,with the outward stomata showing bicyclical distribution. There was one layer of cells in the palisade tissue and 3-4 layers of cells in the spongy tissue. In the primary structure of the stem,the epidermis was slightly keratinized,with 5-6 layers of collenchyma cells and5-7 layers of parenchyma cells inside the epidermis,and an ectophloic vascular bundle. Inthe secondary structure of the stem,the outer cuticle of the epidermis was thickened,and there were 3-4 layers of cells in the cork layer,one layer of cells in the cork cambium,and 2-3 layers of cells in the phelloderm inside the epidermis. Furthermore,the vascular bundles were closely arranged in rings, the secondary phloem and secondary xylem were welldeveloped,and there were 2-3 layers of cells in the cambium. The anatomical structures of the vegetative organs of P. bournei exhibited characteristics of a shade plant,but also showed certain adaptability to sunlit and drought-prone environments.