摘要: WHEN the meristematic cells of root tips are damaged by surgery, X-rays or various chemical treatments, quiescent centre (Fig. 1) stimulated into mitosis. These normally have an average rate mitosis about one-tenth that their neighbours more than half them not in mitotic cycles and, those are, some a “fast” cycle three four times as long neighbours1. After X-irradiation there is immediate response suggests balance cell proliferation between different regions meristem simple competition effect. One stimulatory action removal cap2 and I now found cap exerts complex effect on rest meristem.