Abstract: In order to screen out Medicago sativa varieties resistant to calcium stress, 14 alfalfa varieties were selected as experimental materials, and Hoagland nutrient solution with different Ca²⁺ concentrations was configured to simulate calcium habitats for seed germination tests. Germination indexes, morphological indexes and biomass indexes were determined. The calcium tolerance of alfalfa cultivars during seed germination was evaluated using membership function method. The results showed that under 0-320 mmol·L^-1 calcium concentration, the germination rate and germ length of most alfalfa varieties first increased slightly with the increase of calcium concentration and then showed a downward trend, and the higher the calcium concentration was, the greater of the decline range was . In the range of 120 mmol·L^-1 calcium concentration, there were significant differences in germination rate among varieties （P<0.05）, which could be regarded as the inflection point concentration. The optimal germination concentration ranged from 0.4 to 4 mmol·L^-1, semi-lethal concentration ranged from 120 to 160 mmol·L^-1, and lethal concentration ranged from 160 to 200 mmol·L^-1. The calcium resistance of 14 varieties was divided into 5 groups by cluster analysis. Based on the comprehensive evaluation results of membership function, ‘WL525HQ’ variety with the strongest calcium tolerance and ‘WL656HQ’ variety with the weakest were selected. The results showed that alfalfa ‘WL525HQ’ variety had strong calcium tolerance and survival ability under high calcium stress. It suggested that alfalfa ‘WL525HQ’ variety should be the first choice for planting and promoting alfalfa forage in karst area.

Key words: Alfalfa, Karst, Calcium habitat, Seed germination, Calcium tolerance evaluation

摘要： 为筛选出耐钙胁迫的紫花苜蓿（Medicago sativa）品种,本研究选取14个紫花苜蓿品种作为试验材料,配制不同Ca²⁺浓度的霍格兰营养液模拟钙生境进行种子萌发试验,通过测定发芽指标、形态指标、生物量指标,基于隶属函数法综合评价紫花苜蓿品种间种子萌发期的耐钙性。结果表明：在0~320 mmol·L^-1钙浓度下,大多数紫花苜蓿品种的发芽率、胚芽长等指标随钙浓度提高先略微上升后呈下降趋势,且钙浓度越高下降幅度越大,其中在120 mmol·L^-1钙浓度下各品种间发芽率产生显著差异（P<0.05）,可视为拐点浓度；最适宜的发芽浓度为0.4~4 mmol·L^-1,半致死浓度为120~160 mmol·L^-1,致死浓度为160~200 mmol·L^-1。通过聚类分析将14个品种的抗钙能力划分为5个类群。基于隶属函数综合评价结果筛选出耐钙能力最强的品种为‘WL525HQ’,最弱的为‘WL656HQ’。研究结果表明紫花苜蓿‘WL525HQ’品种在高钙胁迫下具有较强的耐钙性和生存能力,建议将该品种作为岩溶区紫花苜蓿牧草种植推广的首选品种。

关键词: 紫花苜蓿, 岩溶, 钙生境, 种子萌发, 耐钙评价