甜瓜果实发育的组织结构观察

采用石蜡切片技术对甜瓜果实发育的组织结构进行了观察。结果表明：甜瓜外果皮包括表皮、气孔器和表皮毛,在幼果生长过程中,外表皮细胞主要进行垂周分裂,以适应果实体积的增大,随着果实的逐步发育,表皮细胞间隙逐渐填充一些含有木质素成分的物质,并在表皮细胞表面形成一层较厚的角质层。中果皮分为上中果皮和下中果皮,上中果皮包括薄壁细胞和横向伸长细胞,下中果皮则主要包括海绵组织和其中的维管束。幼果期,中果皮细胞排列紧密,各部分细胞大小及形态无明显差异。随着果实的发育,细胞分裂速度减慢,细胞体积不断增大,中果皮细胞径向直径呈现出梯度变化,由外向内逐渐增大。在果实成熟过程中,下中果皮大部分细胞高度分散,细胞壁破裂,细胞互相融合。构成细胞壁的纤维素成分快速溶解,果实软化成熟。

Histological Structure Observation on Fruit Development of Melon

We observed the histological structure of melon(Cucumis melo L.)fruit development by paraffin section method.The results indicated that the exocarp of melon was composed of epidermis,stomatal apparatus and epidermis hair.The cleavage of the exocarp cells is mainly in vertical direction to make fruit expand during young fruit growth.With fruit development,there are some substances containing xylogen filled in the spaces of epidemis cells and there is a quite thick cuticle layer formed on the surface of epidermis.Melon mesocarp can be divided into outer mesocarp including parenchyma cells and elongation cells and inner mesocarp composed of spongy tissue and vascular bundle.Mesocarp cells arrange close and the size and appearance of all cells have no big differences at the young fruit stage.The cleavage of mesocarp cell becomes slow and the cell volume is larger and larger as the fruit develops.When the fruit is maturing,the walls of some cells in the inner mesocarp break up and cells inoculate each other.The cellulose,a component of cell wall begins to dissolve,and finally,the fruit becomes soft and mature.