Abstract: To discuss effects of ⁶⁰Co-γ radiation on differentiation of alfalfa calli and changes of endogenous level,calli and differentiated seedlings induced from plant leaves of non irradiated and irradiated alfalfa seeds (radiation doses 600 and 800 Gy) were used as experimental materials(marked as CK,G600,G800). Differentiation culture of calli in MS medium supplemented with 2,4-D and 6-BA and use high-performance liquid chromatography to determine the changes in the levels of three endogenous hormones in calli and differentiated seedlings. The results showed that when the concentration of additional hormones in MS medium is 2.00 mg·L^-1 2,4-D and 1.00 mg·L^-1,the bud differentiation rates of CK,G600,and G800 callus were 100%,375% and 115%,respectively. Calli with bud points can differentiate into roots,stems and leaves in MS medium without hormones. The IAA content in roots,stems and leaves of CK,G600 and G800 differentiated seedlings was lower than that of calli,and the GA₃content of was higher than that of calli. The ABA content was the highest in roots. The IAA/ABA ratio of CK,G600 and G800 was the highest in calli,and the GA₃/ABA and IAA/GA₃ratio was the highest in stems. Therefore,changes in the levels of exogenous and endogenous hormones can achieve buds point generation and redifferentiation of alfalfa calli. A certain dose of radiation treatment can promote the redifferentiation of alfalfa calli and affect the changes in endogenous hormone levels.

Key words: Alfalfa, ⁶⁰Co-γ radiation, Callus, Plant hormones, Redifferentiation

摘要： 为探讨外源激素和⁶⁰Co-γ辐射对苜蓿愈伤组织分化和内源激素水平变化的影响，本研究以未辐射和辐射苜蓿种子(辐射剂量600 和 800 Gy)植株叶片诱导的愈伤组织和分化苗为试验材料(标记为CK，G600，G800)，将愈伤组织在附加2,4-D与6-BA的MS培养基中进行分化培养，利用高效液相色谱法测定愈伤组织和分化苗中3种内源激素水平的变化。结果表明：MS培养基附加激素浓度为2.00 mg·L^-12,4-D和1.00 mg·L^-16-BA时，CK，G600，G800愈伤组织芽点分化率分别为100%,375%，115%，带芽点愈伤组织在无激素MS培养基均可分化出根、茎和叶。分化苗CK，G600，G800根、茎和叶的IAA含量均低于愈伤组织，GA₃含量高于愈伤组织，ABA含量在根中最高，IAA/ABA比值在愈伤组织中最高，GA₃/ABA和IAA/GA₃比值在茎中最高。因此，外源和内源激素水平的变化可实现苜蓿愈伤组织芽点产生和再分化，一定剂量辐射处理可促进苜蓿愈伤组织再分化，并影响内源激素水平的变化。

关键词: 紫花苜蓿, ⁶⁰Co-γ辐射, 愈伤组织, 植物激素, 再分化