苏铁水生根的解剖结构研究

Study on the Anatomy of Hydroponic Roots of Cycas revoluta

[目的]探索苏铁根的形态与解剖结构及其对水生环境的适应能力。[方法]选取苏铁一年生健康实生苗,植株脱土后进行水培,并运用石蜡切片技术,对苏铁水生根和土生根(CK)进行外部形态与内部结构比较。[结果]苏铁能适应水生条件,在水培条件下具有生根能力;苏铁水生根是由根基部不定根长成的须根系;皮层和栓内层的细胞活力强,经过这些细胞分裂、生长和分化产生的愈伤组织覆盖根表,形成凹凸不平的奇特外观;中柱鞘不明显,中柱不发达,机械组织也呈弱化简化状态;木质部二原型,相当于土生根的初生木质部,其中有螺环纹导管。[结论]为今后苏铁的栽培管理和开发利用,以及系统研究提供了解剖学依据。

[Objective]To explore the morphology and anatomy of Cycas revoluta root and its adaptability to aquatic environment.[Method]The annual healthy seedlings of C.revoluta were selected,and the plants were stripped and hydroponic cultured.The external morphology and internal structure of the hydroponic roots and terrestrial roots(CK)of C.revolutas were compared by paraffin section technology.[Result]The results showed that C.revoluta could adapt to aquatic conditions and grow new roots in hydroponic environment.Hydroponic roots of C.revoluta were fibrous roots grown from adventitious roots.The cells of the cortex and phelloderm were very vigorous.The callus resulted from these cells’amitosis,growth,cytodifferentiation and replaced the root’s epidermis,forming a strange uneven appearance.The pericycle was not obvious,the stele was not developed,the mechanical tissue grew weaker and simpler so on.The xylem was diarch,in which found spiral vessels and annular vessels,equivalent to the primary xylem of terrestrial roots.[Conclusion]It provides anatomical basis for the cultivation,management,development and utilization of C.revoluta in the future,as well as systematic research.