竹笋形态发育构建过程中解剖结构及化学成分的动态变化

竹笋生长点具有典型的原套原体结构,原套原体向外突起产生箨原基和腋芽原基,并逐渐发育为箨和腋芽。亚顶端分生组织区的髓分生组织区发育成髓腔;周围分生组织分化出表皮、皮层、内皮层以及分布在基本组织中的维管束,最后发育成秆壁;周围分生组织的形成层向髓层弯曲,分化出节隔维管束,并进一步发育成节隔。在竹笋发育成竹的过程中,居间分生组织仍保留旺盛的分生能力,通过持续的横向分裂,促进植株的高生长,直至嫩竹形成。毛竹笋期的纤维素、木素和多戊糖的相对含量均较低,在竹笋发育过程中,纤维素增长最快,多戊糖次之,木素增加最慢;笋期的苯醇抽提物含量较高,但随着笋龄的增长,其含量呈现降低趋势。

Dynamic Change of Anatomical Structure and Chemical Constitutes of Bamboo Shoots for Phyllostachys pubescence at Developmental Stage

It is important to study the development,anatomical change and chemical constitutes of bamboo shoot in understanding bamboo mechanical properties and using bamboo resources.The structure of growing point of bamboo shoot shows a typical tunica-corpus structure,and the primordias of sheath and axillary bud come from the base of the growing point,and gradually develop into shell and axillary bud by growing outward.Inferior top is divided into marrow meristem area and circumambience meristem area,marrow meristem area then evolves into marrow,and circumambience meristem area evolves into epidermis,cortex,interior cortex and vascular bundle distributing in ground tissue,and developes into a stalk wall finally;cambium in circumambience meristem area crooks toward marrow,and developes into partition vascular bundle.At the developmental stage of bamboo shoot becoming bamboo,mediacy mesistem keeps vigorous ability and promotes the height growth of the plant by continuously horizontal division until the tender bamboo takes shape.The relative contents of cellulose,lignin and polypentose in Phyllostachys pubescence shoot are relatively low,which are 10.87%,6.43% and 14.64% respectively.In the course of development of the bamboo shoot,the cellulose increases fastest,and then followed by polypentose and lignin in order.Content of extraction by benzene-alcohol is relatively high,and tends to reduce with bamboo shoot growing.