二月兰根系发育形态学研究

二月兰Ｏｒｙｃｈｏｐｈｒａｇｍｕｓ ｖｉｏｌａｃｅｕｓ Ｏ．Ｅ．Ｓｃｈｕｌｚ为二年生草本植物，直根系。初生结构为二原型，次生结构发达，主侧根结构相同。形成层活动随季节有明显变化，木质部可见年轮。冬季吸收根不死，无越冬根原基产生，吸收根连续不断更替，无明显季节性变化。根内淀粉含量随发育时期的变化而相应变化，其积螺高峰有两个，分别出现在第一年越冬前及第二年返青后开花前，不同播期对根系积累营养及第二年植

STUDY ON DEVELOPMENTAL MORPHOLOGY OF ORYCHOPHRAGMUS VIOLACEUS ROOT SYSTEM

Orycllophragmus violaceus is a biennial herb,its root system is a tap root system tvith secondary structure.The primary xylem of man root is diarch and secondary xylem is well developed.In lateral root,there is same structure with the main root.Activity of cambium is variable with the seasons, thus a growth ring can be seen in the cross section. In winter,the absorb roots are still alive and there isn't any overwintering root primordium.The old absorb roots are replaced by the new ones continuously, and we can't see periodicity changes obviously. The amount of starch in the root changes with seasons and developmental stages.The two peaks of starch accumlation appear before winter comes and after the plant turns green in the second year. Different seeding date can influence the accumulation of starch and the plant turning green in the spring. Study on developmental morphology of O.violaceus root system not only possesses theoretical significance for the understanding ofits root system completely and correctly, but also guides its cultivation and managment.