| 【Objective】In order to provide theoretical guidance for the ecological adaptability of Paranephelium
hainanensis, a plant species with extremely small populations (PSESP) in Hainan Province, we explored the anatomical
structure and water transport mechanism of this species.【Method】The anatomical structure of leaf, stem, root and aerial
root of P. hainanensis were observed by paraffin sectioning method.【Result】The leaf of P. hainanensis belonged to
bifacial leaf, on which there were thick cuticles. The palisade tissue cells arranged in the leaf surface vertically, with a
thickness of 66.71 μm. There were 5-7 layer cells in spongy tissue, which arranged loosely. In the primary structure of
stem, the vascular bundle arranged closely in two rounds. There were obvious vessels on the xylem and the xylem was not
developed. However, stem had developed phloem and marrow. In the primary structure of the root, the cortex was developed,
accounting for 54.7% of root’s radius. The vascular bundle was highly lignified, but the phloem was underdeveloped. The
small diameter and less number of vessels of P. hainanensis showed that the water storage capacity was poor in the root. The
aerial roots of P. hainanensis were composed of cork, cortex, xylem, phloem and marrow. There were 3-5 lay cells in the cork
and the marrow structure was developed, accounting for 34.60% of the radius.【Conclusion】P. hainanensis had droughttolerance structure characteristics. The seedlings were not resistant to high temperature and strong light and they were suitable
to grow under the forest with moderate canopy. It is suggested that attention should be paid to the adaptability of P. hainanensis
to the habitat while conducting ex situ conservation. |
