珍稀濒危植物翅果油树表皮毛的微形态观察研究

The micromophology observation of rare and precious plant-"wingfruit" elaeagnus

利用体视显微镜、扫描电镜和光学显微镜,对珍稀濒危植物翅果油树 ElaeagnusmollisDiels 的茎、叶、果、休眠芽等多种器官表面覆盖的表皮毛,进行了详细观察.发现其表皮毛的形态和结构具有多样性,各器官有差异,据此将它们分为分支状毛、星状毛、盾状-星状毛、盾状毛四类,以及一些特殊的表皮毛,如:分支状毛与星状毛或盾状-星状毛的过渡类型称为类星状毛和类盾状-星状毛.叶片上表面的表皮毛,为分枝状表皮毛,且稀疏散布.叶片下表面的白色表皮毛,也多为分枝状表皮毛,但分布较密,叶主脉处最为稠密多为星状毛.叶柄的表皮毛形态呈现一定的梯度变化,远轴端 靠近叶片端 为类星状毛,近轴端 靠近茎的一端 为盾状-星状表皮毛,中间段为星状毛介于前二者之间.茎表面灰色的或褐色的表皮毛,以盾状表皮毛为主,夹杂少量盾状-星状表皮毛,因茎的老嫩其表皮毛形态略有不同.外果皮沟槽内的表皮毛多为盾状表皮毛,嵴部则密集星状或分支状表皮毛.休眠芽的鳞片多覆盖盾状表皮毛,只在鳞片的尖端有少量星状毛和分枝状毛.翅果油树多种器官表面多种表皮毛的存在是其适应高山 海拔800～1300m 环境的一种形态特征.表皮毛具有反射阳光、阻止水分过度散失、保温、防止机械损伤等功能.为探究翅果油树耐旱、耐寒。

The author had a detailed observation of trichomes on the surface of various organs of rare and precious plant-'wingfruit' elaeagnus under scanning electron microscopy (SEM) and stereomicroscope.In the meantime,the transection detail of leaves,leaf stalk and stems were obtained under optical microscope.The result shows that trichomes on different organs surface have various micromorphologies and structures,we classified them into four categories:(1) branchy trichomes;(2) stellate hairs;(3) peltate-stellate hairs;(4) peltate hairs and some special types named as stellate-like hairs or peltate-stellate-like hairs.Which have one to two single hair coming out from the center protruding site of stellate hairs or peltate-stellate hairs.The trichoms of adaxial surface of leaf are branchy hair and sparsely distributed,but the branchy white hair on the abaxial surface of leaf always densely distributed,and the more dense site is at midrib located with stellate hairs.Along leaf stalk from abaxial end to adaxial end,stellate-like hairs;stellate hairs;and peltate-stellate hairs distributed successively.As for the trichoms on stem surface,gray or brown color,mainly are peltate hairs scattered with peltate-stellate hairs,and tirchoms have some difference between young stems and old stems.Under SEM a fruit coat surface showing peltate-stellate hairs in gully and branchy hairs on ridge.Out side and second layer bud scale surface of a axillary dormant bud mostly covered with peltate hairs,only on the tip of scale located with some stellate hairs or branchy hairs.Various organ surface of Elaeagnus mollis Diels covering with trichoms confirmed this plant with morphological characteristics to adapt high mountain environment,because trichoms have multiple functions such as temperature regulation,increased light reflectance (including UV),decreased water loss through reflection,reduced mechanical abrasion,seed dispersal,and so on.This trichoms morphological research have helped us understand the mechanism of drought tolerance;cool tolerance and high temperature tolerance of Elaeagnus mollis Diels,and also released the easy pollution reason of explants on media during tissue culture of Elaeagnus mollis Diels.This work have laid a foundation for us to continue studying the trichoms differentiation,development and molecular biology.