4种野豌豆种子萌发对水分胁迫的响应

以3种青藏高原野豌豆属植物窄叶野豌豆（Vicia angustifolia）、山野豌豆（V.amoena）、歪头菜（V.unijuga）与1种当地栽培植物箭筈豌豆兰箭3号（V.sativa）种子为材料，应用种子萌发的水势模型对上述4种植物种子萌发对水分的需求特性进行了研究。结果表明，1）基础水势（Ψb）随种子萌发率（g）的增加而增加，表明种群内种子个体萌发基础水势存在变异；2)除歪头菜外，其余种子的萌发速率与水势的回归直线的斜率随萌发率的增加而降低，暗示种群内种子个体萌发的水势时间值(θH)在有些种上可能存在变异；3）参试植物种中，兰箭3号种子的Ψb值最低，表明其在相对干旱环境条件下易于萌发，山野豌豆种子的Ψb值最高，但θH较低，表明其萌发耐旱性差，在水分充足的条件下萌发迅速；4）水势模型可准确预测休眠破除后4种野豌豆属种子在高水势条件下的萌发进程，但用于预测低水势条件下种子的萌发时，准确性较差。

Response of four Vicia species seed germination to water stress

This study investigated seed germination characteristics of four Vicia species from Tibet Plateau under different water potential. The results were summarized in terms of the hydrotime model as following: 1)The base water potential increased as the sub population(g) increasing, indicated that the base water potential varied with individual in a seed population; 2) Except Vicia unijuga, the slope of regression line of germination rate and water potential decreased as the sub population increased, implied that the hydrotime was not constant in some cases; 3) Compared to other species, V.sativa attained the lowest base water potential, it showed that this species can germinate in the relative drier condition; V.amoena attained the highest Ψb with the lowest hydrotime constant(θH), implied that this species will not germinate in the drought condition, but a rapid seed germination may be expected in the favorable water condition; 4) The germination process could be well described by hydrotime model when the water potential was high, however the accuracy significantly decreased when subjected to low water potential approaching to seed germination.