人参根系发育形态学的研究

人参(Panax qinseng C. A. Meyer)属于直根系植物,有次生构造。一年生苗只具有主根和侧根。二年以上的人参常在根状茎上长出不定根,即人参根系包括主根和不定根及其各级分枝。主根初生木质部为三原型,侧根和不定根及其分枝多为二原型,偶见三原型。根系随参龄的增加而增大。每年末级分枝自基部于休眠前萎缩、脱落,并在萎缩部分的上一级支根内部产生越冬根原基,越冬根原基是翌年形成全部吸收根的基础。一年生人参由中柱鞘产生一圈初生树脂道,由形成层产生一圈(或二圈)次生树脂道,以后次生树脂道的圈数随参龄的增加而每年增加一圈,自第五年开始渐缓。根内淀粉粒含量随发育时期的变化而相应变化,其积累高峰出现在果后期。研究人参根系发育形态学不仅对全面正确认识人参根系具有理论意义,而且对改进人参栽培管理和评价人参质量具有指导意义。

STUDY ON DEVELOPMENTAL MORPHOLOGY OF GINSENG ROOT SYSTEM

The root system of ginseng is a tap root system. One year seedling only has main root and lateral roots, and adventitous roots often arise from the rootstock when it is more than two years old. Therefore, ginseng root system includes main root, adventitous roots and their branches. Primary xylem of main root is triarch, lateral roots, adventitous roots and branches at all levels are mostly triarches, rarely diarch. Root system increase with age adding. Before dormacy the last branches wither and fall, and winter root primodia are produced in higher order branches near withered positions every year. Those are the base of formation of all absorbing roots next year. One year ginseng produces one ring (or two rings) secondary resin ducts from cambium. Afterwords, one ring secondary resin ducts increase with age adding and the increasing becomes slowly from five year ginseng. The amount of starch in the root changes with developmental stages. The peak of starch accumulation appears after fruit stage. Study on developmental morphology of ginseng root system has not only theoretical signifi- cance for understanding ginseng root system completely and correctly, but also guiding meaning for improving the cultivation and management and appreciating the quality of ginseng.