干旱胁迫对砂生槐种子萌发和幼苗生长的影响
Effect of drought stress on seed germination and seedling growth of Sophora moorcroftiana

【目的】研究干旱胁迫对不同种源砂生槐种子萌发及幼苗生长的影响，筛选最耐旱的砂生槐种源。【方法】2013-10，以采自西藏不同地区的13个种源砂生槐为研究对象，用质量浓度为0，50，100，150，200，250和300 g/L的PEG6000模拟干旱胁迫，分析干旱胁迫对13份不同种源砂生槐种子萌发及幼苗生长的影响，并选用200 g/L PEG6000胁迫下的发芽率、发芽势、发芽指数、上胚轴长、下胚轴长、胚根长等6个指标对不同种源砂生槐进行耐旱性评价。【结果】13个种源砂生槐种子纵径、横径、硬实率和千粒质量4个基本特征间存在一定差异：种子纵径为4.60～5.19 mm，种子横径为3.70～3.98 mm，硬实率为87.00％～100.00％，千粒质量为38.19～47.14 g。低质量浓度（50～150 g/L）PEG6000对砂生槐种子发芽率、发芽势有一定程度的促进作用，当PEG6000质量浓度高于200 g/L时，发芽率、发芽势均明显降低。当PEG6000质量浓度为0～300 g/L时，随着PEG6000质量浓度的增大，除贡嘎县江塘镇（GJT）种源外，其他种源种子的发芽指数总体上均呈逐渐下降趋势。总体上看，当PEG6000质量浓度为0～100 g/L时，各种源幼苗上胚轴长均较高；PEG6000质量浓度高于150 g/L时，不同种源幼苗上胚轴长明显降低；PEG6000质量浓度为200 g/L时，幼苗的上胚轴很短或为0；而在PEG6000质量浓度为250～300 g/L时，所有幼苗未长出上胚轴。在0～150 g/L PEG6000胁迫下，13个种源幼苗下胚轴长变化幅度并不大；当PEG6000质量浓度高于200 g/L时，下胚轴长明显下降， 在300 g/L PEG6000胁迫下，13个种源砂生槐幼苗下胚轴长均为0 mm。在PEG6000质量浓度为0～150 g/L时，幼苗胚根长总体较高但变化幅度不大；当PEG6000质量浓度为200 g/L时，除南木林县艾玛乡（NML）种源外，其他种源幼苗的胚根长开始较大幅度下降；当PEG6000质量浓度为250 g/L时，胚根长进一步下降，其中有7个种源的幼苗胚根长为0 mm；当PEG6000质量浓度为300 g/L时，所有种源幼苗的胚根长均为0 mm。耐旱性综合评价结果显示， 13个种源中，有2个种源属耐旱型，3个种源属较耐旱型，1个种源属中间型，4个种源属干旱较敏感型，3个种源属干旱敏感型。【结论】适宜的干旱胁迫对砂生槐种子的萌发和幼苗生长有一定促进作用；13个种源中，采自南木林县艾玛乡（NML）和朗县金东乡（LJD）的砂生槐耐旱性最强。
【Objective】This paper studied the effects of drought stress on seed germination and seedling growth of Sophora moorcroftiana from different provenances to screen the most drought resistant provenances.【Method】In October 2013,the effects of PEG6000 (simulating drought stress) at different mass concentrations (0,50,100,150,200,250 and 300 g/L) on seeds germination and seedling growth of 13 provenances were examined,and the drought resistant capacities of S.moorcroftiana from different provenances under 200 g/L PEG6000 stress were evaluated using six indexes including germination percentage,germination energy,germination index,epicotyl length,hypocotyl length,and radicle length.【Result】Differences existed among 13 provenances in four basic features including seed length,seed width,percentage of hard seeds and 1 000 seeds weight of S.moorcroftiana:the seed length was 4.60－5.19 mm,the seed width was 3.70－3.98 mm,the percentage of hard seeds was 87.00％－100.00％,and the 1 000 seeds weight was 38.19－47.14 g.The germination rate and germination energy were promoted by PEG6000 at low mass concentrations (50－150 g/L),but were decreased significantly when the mass concentration was above 200 g/L.With the increase of the PEG6000 mass concentration within 0－300 g/L,the seed germination index from all provenances except GJT generally declined.Overall,when th