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

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 and 5-7 layers of parenchyma cells inside the epidermis, and an ectophloic vascular bundle. In the 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 well-developed, 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.