渗透胁迫下水稻种子萌发特性及抗旱性鉴定指标研究

用聚乙二醇（PEG）-6000作为渗透剂模拟干旱胁迫，探讨在4种不同浓度的渗透胁迫下水稻种子的萌发特性，并确立间接评价水稻苗期抗旱性的萌发期鉴定指标。结果表明，高浓度渗透液对种子萌发的抑制作用明显大于低浓度，萌发率的干旱胁迫反应指数随渗透液浓度的降低和萌发进程而增加。在不同浓度的渗透胁迫处理中，20％浓度下萌发6d后的萌发率表现较大的变异幅度和变异系数以及较均衡的品种频率分布，较好地反映了水稻种质对渗透胁迫的不同反应，认为20％／6d条件较适合作为萌发率鉴定的渗透液模拟干旱胁迫；经反复干旱后的幼苗存活率与萌发胁迫指数和20％胁迫浓度下萌发8d后芽鞘长的干旱胁迫反应指数（DRI）表现极显著或显著正相关，认为萌发胁迫指数和芽鞘长的DRI可作为评价水稻苗期抗旱性的间接鉴定指标。

Study on Characteristics of Germination and Drought-resistance Index by Osmotic Stress in Rice

Polyethylene glycol(PEG)-6000 was employed as osmotic agent for simulating water stress,to study the germination characteristics of rice grain in four difference concentrations osmotic solution and to establish the identification index for indirectly evaluating drought-resistance in germination period.The result showed that the inhibiting on seed germination in higher concentration of PEG was larger than that in lower concentration of PEG,and drought response index of germination rate was increased along with the decrease of PEG conentration and the course of germination.Germination rate after germinated 6 days in 20% concentration of PEG had more variance range and coeffecient of variation,better proportion on variety distributing than other's,it could reflect different response of rice variety on osmotic stress,so it was fit for drought-resistance identification on germination rate.Survival rate of seedling treated drought repeatedly was significantly correlated with the index of germination in osmotic stress and coleoptile length after germinated 8 days on 20% concentration of PEG,so index of germination and coleoptile length could be used as identification index for indirectly evaluating drougt-resistance at the seedling stage.