野生朱砂根果实发育各阶段微形态观察

Micro-Morphological Features in Different Fruit Development Stages of Ardisia crenata

为研究朱砂根(Ardisia crenata Sims)植物果实各阶段的微形态发育特征,运用电子扫描显微镜进行了形态观察。发现朱砂根果实具有典型的核果特征,其果皮由外果皮、中果皮和内果皮组成;外果皮较薄,中果皮较厚,内果皮木质化。外果皮表面纹饰为短棍棒状、海绵状、不规则形状等,呈现出较为规则的变化,从幼果到成熟排列上都比较紧密,但纹饰由小到大、由皱褶到平滑。中果皮在幼果时皮层里面填充细胞较多,种子发育较小,因此中果皮厚度最大,随着成熟度的增加,中果皮变薄,种子部分不断膨大,最终达到一个稳定状态;中果皮细胞大小与中果皮厚度呈正比。种子内部结构较为致密,种子间具孔,孔呈不规则形状,大小不等,类似海绵纹孔;孔纹壁网状或具细纹。随着果实成熟度的增加,种子孔径不断缩小,日趋稳定,孔纹壁也逐渐光滑,纹理较为稀疏。

Fruit micromorphological characteristics of Ardisia crenata Sims at different development stages were observed under scanning electron microscope. The fruits of A. crenata are composed of exocarp, mesocarp and endocarp and have the characteristic of typical drupe, of which the exocarp is thin while mesocarp is thick and endocarp is woody. The surface ornamentation of exocarp is short clavate, cavernous, irregular shape etc, showing an regular change as the arrangement from young to mature is relatively close while the ornamentation changes from small to big, from wrinkles to smooth. Mesocarp layer in young fruit is filled with cells, and the seed development is small, so the mesocarp is the thickest. With the increase of maturity, mesocarp become thinner while germplasm part expand, which eventually reaches a steady state. The size of cells is positively correlated with the thickness of mesocarp. The internal structure of seeds is relatively dense, and there are holes of irregular shape and different sizes, similar to sponge pit. Pitted wall is meshy or has fine lines. Pore diameter reduces with the increase of maturity, and has increasing stability. Seeds pitted wall also become smooth gradually while the texture is relatively sparse.