不同生态环境下水曲柳的解剖结构差异分析

Difference Analysis of Anatomic Structure of Fraxinus mandschurica Rupr in Different Ecological Environments

[目的]探究在阴生和阳生2种环境下水曲柳演化出不同内部解剖结构特征。[方法]采用石蜡切片技术、木材离析技术、徒手切片及光学显微摄影技术,分别对阴生和阳生环境下水曲柳(Fraxinus mandschurica Rupr.)叶柄和叶片、木材切面以及木质部导管的结构进行比较研究。[结果]阴生环境下,水曲柳叶柄和叶片的角质层不发达,叶肉细胞通气组织发达,海绵组织不发达,栅栏组织稀疏,导管分子孔径较小,气孔稀疏,表现出植物耐阴性的结构特征。阳生环境下,其叶柄和叶片都表现出切向壁角质层加厚,叶肉细胞小而致密,栅栏组织层数较阴生多,海绵组织致密,可有效折射光强,避免叶片灼伤,维管组织发达,导管孔径较大,运输能力较强,是植物为适应干旱环境所演化出的特有结构。[结论]试验结果为进一步探究植物颉颃逆境及结构植物学的基础研究提供了理论依据,证实了植物内外部形态与环境密切相关。

[ Objective] To explore the Fraxinus mandshurica Rupr evolution of different internal anatomical characteristics in the shade environment and sun environment. [ Method] Employing paraffin-section method,wood segregation technology, unarmed slice method and optical micrograph technology ,we performed a comparative study on the structure of petiole,leaf,timber and xylem vessel of Fraxinus mandshurica in the two kinds of circumstances respectively. [ Result] In the shade environment,its cuticle of petiole and leaf was underdeveloped, and aerenchyma mesophyll cells were developed. Spongy tissue was underdeveloped, and palisade tissue was sparse. The diameter of vessel elements and smaller and stomatal sparse,showed the structure characterstic of tolerance of shade environment. In the sun environment,its petiole and leaf showed the tangential wall corneons layer thickening,mesephyll cells were small and compact. The layer number of palisade tissue was more. Spongy tissue was dense. It could refract light intensity effectively in order to avoid leaf burns. Vascular tissue was developed. Vessel diameter was bigger ,and made the ability of transport strengthen. These were the unique structure of the plant in order to adapt to the drought environment. [ Conclusion ] The results provide theoretical support for further exploring the rivalry adversity of plant and anatomical structure,and confirm the plant internal and external morphology is closely related to the environment.