Abstract: In order to establish a stable,rapid and efficient tissue culture system on different cultivated alfalfa (Medicago sativa) varieties,this experiment took the varieties 'Tourist’'Paola’ and 'Sardi7’ as the research materials,investigated the effects of alfalfa explants,hormones ratio and metal ions (Cu²⁺,Ag⁺) on induction of embryonic callus. The results showed that hypocotyl was the best explants to induce callus. When MS+1 mg·L^-1 2,4-D+0.2 mg·L^-1 KT were cultured,embryogenic callus induction rates of 'Tourist’ and 'Paola’ were 24.7% and 16.7% respectively. And the embryogenic callus induction effect of 'Sardi7’ was 27.3% when MS+2 mg·L^-1 2,4-D +0.2 mg·L^-1 KT were cultured. 1 μmol·L^-1 and 5 μmol·L^-1 Cu²⁺ could promote callus induction of 'Sardi7’,'Tourist’ and 'Paola’ significantly. 5 μmol·L^-1 Ag⁺ significantly induced embryogenic callus of 'Tourist’ and 'Paola’,and the induction rates increased by 25.3% and 46.7%,respectively (P<0.05). In this study,we explored the best explants to induce alfalfa callus and their culture conditions,as well as the role of metal ions in promoting regeneration of different alfalfa varieties,which provided a solution for breaking through the genotypic restriction of autotetraploid cultivated alfalfa varieties and improving the healing rate of embryonic callus.

Key words: Alfalfa (Medicago sativa), Hypocotyl, Metal ions, Embryogenic callus, Microscopic observation

摘要： 为在不同栽培苜蓿(Medicago sativa)品种上，建立稳定、快速且高效的组织培养体系，本试验以品种'游客’、'Paola’和'Sardi7’为研究材料，探究了苜蓿外植体、激素配比及金属离子(Cu²⁺、Ag⁺)，对其胚性愈伤组织的诱导效果。结果表明：下胚轴为诱导愈伤组织的最佳外植体；MS+1 mg·L^-12,4-D+0.2 mg·L^-1 KT为培养基时'游客’和'Paola’胚性愈伤诱导率分别为24.7%，16.7%；MS+2 mg·L^-12,4-D+0.2 mg·L^-1 KT为培养基时'Sardi7’胚性愈伤诱导效果最佳为27.3%；1 μmol·L^-1 和5 μmol·L^-1 Cu²⁺均能显著促进'Sardi7’'游客’和'Paola’愈伤组织的诱导；5 μmol·L^-1 Ag⁺显著诱导'游客’和'Paola’形成胚性愈伤组织，诱导率分别提高25.3%,46.7%(P<0.05)。本研究探索了诱导苜蓿愈伤组织的最佳外植体及其培养条件、金属离子促进不同苜蓿品种再生的作用，为突破同源四倍体栽培苜蓿品种基因型上的限制、提高胚性愈伤组织出愈率提供了思路。

关键词: 紫花苜蓿, 下胚轴, 金属离子, 胚性愈伤, 显微观察