γ射线对苜蓿离体培养与植株再生的影响

以5个紫花苜蓿品种为材料,用于叶与下胚轴为外植体进行0—16kR的辐射处理,研究了不同照射量γ射线对出愈率、愈伤组织鲜重、体细胞胚诱导率和植株再生的影响。结果表明,子叶外植体的辐射敏感性高于下胚轴,2kR对愈伤组织的形成与生长、体细胞胚的产生和植株再生有不同程度的刺激作用;16kR完全抑制子叶愈、信组织的形成和生长。用英648和集宁两个品种的愈伤组织进行0—8kR的处理,结果发现,低于2kR对愈伤组织的生长和体细胞胚的形成具程度不等的刺激作用,8kR对愈伤组织具致死效应。苜蓿育种工作中离体诱变处理的最佳照射量为4—6kR。

EFFECT OF γ-RAY IRRADIATION ON in vitro CULTURE AND PLANT REGENERATION OF ALFALFA

60Co Y-ray irradiation ranged 0-16kR was used,to treat the cotyledons and hypocotyls of 5 cultivars of alfalfa(Medicago sativa L.).The effects of irradiation on the frequency of callus,fresh weight of callus,the frequency of somatic embryo induction and plantlet regeneration were studied.The results showed as follows.The radiosensitivi-ties of cotyledon was significantly higher than that of hypocotyl.Ex-p.osure of 2kR could,improve the growth o.f callus,embryog'enesis and plantlet regeneration at various levels.Exposure of 12kR completely inhibited the callus formation from explants of cotyledon.Callus from two cultivars,England 648 and lining alfalfa,were irradiated with 0-8kR.The results showed that exposure below 2kR could promote the growth of callus and the formation of somatic embryo at different level's.The exposure of 8kR had the effect of lethal.The optimum exposure for genetic improvement of alfalfa in vitro by inducing mutation was considered to be 4-6kR