桃果实维管束的分布及解剖研究

 为了解桃果实输导组织分布及结构特征, 以‘大久保’桃果实为试材, 观察了维管束系统的分支体系和分布状况, 并用石蜡切片技术对维管束组织的解剖结构进行了系统观察。结果表明, 桃果实中的维管束分为骨干、分支和毛细3级, 其中骨干维管束又分为种胚维管束、内果皮维管束和中果皮维管束(腹维管束、背维管束及分布在内果皮两侧着生于果柄的维管束) , 分别为种仁、内果皮、中果皮的物质运输通道。种胚维管束韧皮部极其发达, 并伴有三生结构; 内果皮中分布的维管束韧皮部发达; 腹维管束、背维管束粗大且分支较多, 兼具发达的韧皮部及木质部。分支维管束和毛细微管束主要分布在中果皮中。毛细维管束的特点是韧皮部处有腔, 腔体随着果实的发育不断扩大。形态和结构上的不同是与其功能相适应的, 由此推测种仁和内果皮发育需要的营养物质以有机营养为主, 中果皮发育需要的营养物质则涵括有机物、无机物、水分。

Studies on Anatomy and Distribution of the Vascular Bundles in the Peach Fruit

In order to understand the distribution and structure of vascular tissue in the peach fruit, observation of the branches system and distribution of vascular bundleswas taken with the normal paraffin section and peach (Prunus persica‘Okubao’) fruitwas used asmaterial. The results showed that: Vascular bundles in peach fruit can be divided into three types, main vascular bundle, branch vascular bundle and fibrous vascular bundle. Main vascular bundles include embryo vascular bundle, endocarp vascular bundle and mesocarpvascular bundle (ventral bundle and dorsal bundle, and vascular bundles on endocarp from pedicel). Their functions are that transport nutrition to the seed, endocarp and the mesocarp respectively. Embryo vascular bundle has developed phloem and tertiary structure; Vascular bundles with developed phloem are annularly distributed in the endocarp; Ventral bundle and dorsal bundle are thick, both of them have a majority of branches and developed phloem and xylem. Branch vascular bundles and fibrous vascular bundlesmainly distribute in the mesocarp. The cavity is observed in phloem of fibrous vascular bundle in the mesocarp and it enlargeswith the fruit growth. The structures of vascular bundles accommodate to their functions. It can be speculated that seed and endocarp mostly need organic nutrition and the mesocarp needs organic nutrition, mineral nutri2tion and water.