紫花苜蓿耐羟脯氨酸变异体的筛选及抗性研究

以紫花苜蓿Medicago sativa（敖汉苜蓿和龙牧801苜蓿）种子为材料，培养无菌幼苗。以无菌苗的茎段为外植体，诱导愈伤组织，并用叠氮化钠（NaN3）200 mg/L对愈伤组织进行诱变，以脯氨酸类似物L 羟脯氨酸（L Hyp）作为选择压力，通过在含半致死浓度的L Hyp（8 mmol/L）选择培养基及无L Hyp培养基上交替培养，分离出抗L Hyp的愈伤组织变异体。该变异体以高脯氨酸含量为特征，其脯氨酸含量分别比原型高2.84倍（敖汉）和3.17倍（龙牧801），同时进一步测定其生理生化指标，发现变异体的可溶性糖含量是对照的1.56（敖汉）倍和1.76倍（龙牧801），过氧化物酶（POD）活性与原型相比差异极显著。分别对2种苜蓿愈伤组织进行聚乙二醇（PEG）（敖汉）和低温（龙牧801）胁迫处理，结果显示，变异体具有更强的抗逆性（抗旱、抗寒），能更好的适应恶劣（干旱、寒冷）的生长环境。

Screening and characterizing of L-Hydroxyoroline resistant variants in Medicago sativa

Alfalfa seeds of Aohan and Longmu 801 were used as materials for seedling cultivation,whose explant was used to induce callus and treated with 200 mg/L NaN3 for mutation.The callus was cultured on medium with and without 8 mmol/L Hyp to select mutants.The mutants contained 2.84 times(Aohan) and 3.17 times(Longmu 801) of praline than the wild types.Meanwhile,their soluble sugar content were 1.56(Aohan) and 1.76 times(Longmu 801) higher than the CK.POD enzyme activity was also significantly different compared with the wild type.PEG(Aohan)and low temperature(Longmu 801)treatments indicated that the mutants had stronger stress resistance(drought and cold) more adaptable to harsh environments.