西瓜营养器官解剖学研究

西瓜的营养器官结构如下：（１）幼根由表皮、皮层和维管柱三部分组成，初生木质部为四原型；成熟根具有一定的次生结构，维管束为外韧型。（２）下胚轴的初生结构由表皮、皮层、维管束、髓和髓射线等构成，维管束为双韧型；次生生长时形成层主要存在于外韧皮部和木质部之间，为有限的次生生长。（３）地上茎的结构较复杂，初生结构中维管束排列近两轮；次生生长与下胚轴大致相似。（４）卷须的结构与茎的基本相似。（５）子叶与叶片均由表皮、皮层和叶脉三部分构成，叶片为典型的异面叶。

Study on the Anatomy of Vegetative Organs in Citrullus Lanatus

The structures of vegetative organs in Citrullus lanatus are as follow:(l) The young root comprises epidermis,cortex and vascular cylinder, primary xylem is tetrarch; The mature root is of definite secondary structure,vascular bundle belongs to collateral bundle.(2) The primary structure of hypocotyl consists of epidermis,cortex,vascular bundle,pith and pith rays, vascular bundle belongs to bicollateral bundle.cambium is located mainly between collateral phloem and xylem,the secondary growth is limited.(3)The structure of stem is complicated, vascular bundles in primary structure are arranged in two cycles,the secondary growth is similiar to that of hypocotyl.(4)The structure of stem tendril is similiar to that of stem.(5)The structure both in cotyledon and leaf is composed of epidermis,mesophyll and leaf vein,leaf is typical of bifscial leaf.