| 摘要: |
| 【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。 |
| 关键词: 砂生槐 干旱胁迫 种子萌发 幼苗生长 耐旱性评价 |
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| 基金项目:国家自然科学基金项目(31260189)；西藏特色农牧资源研发协同创新中心建设项目；高原基础生态学术团队能力提升计划项目 |
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| Effect of drought stress on seed germination and seedling growth of Sophora moorcroftiana |
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ZHANG Yan-fu,YAO Wei-jie,GUO Qi-qiang,et al
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| Abstract: |
| 【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 the mass concentration of PEG6000 was 0－100 g/L,the epicotyl lengths of seedlings from all provenances were high,while the epicotyl lengths of seedlings from different provenances decreased significantly when PEG6000 mass concentration was above 150 g/L.When the mass concentration was 200 g/L,the epicotyls lengths were very short or close to 0 mm,and when the mass concentration was 250－300 g/L,all seedlings could not grow epicotyl.Under the stress at PEG6000 concentrations of 0－150 g/L,the hypocotyl lengths of seedlings from all 13 provenances changed slightly, hypocotyl lengths decreased significantly when the mass concentration was above 200 g/L,while hypocotyl lengths of seedlings from all provenances were 0 mm when the mass concentration was 300 g/L.The radicle lengths of seedlings were high with slight variations when the mass concentration was 0－150 g/L,and that of seedlings from all provenances except NML started to decline substantially when the mass concentration was 200 g/L.When the mass concentration was 250 g/L,the radicle lengths decreased further with 7 provenances decreased to 0 mm,while the radicle lengths of seedlings from all provenances were 0 mm when the mass concentration was 300 g/L.Comprehensive drought evaluation showed thatthere were two drought tolerant provenances, three relatively drought tolerant provenances,one intermediate provenance,four relatively drought sensitive provenances and three drought sensitive provenances among the 13 studied provenances.【Conclusion】Suitable drought stress could promote the seed germination and seedling growth of S.moorcroftiana.S.moorcroftiana from NML and LJD were the most drought resistant among all 13 provenances. |
| Key words: Sophora moorcroftiana drought stress seed germination seedling growth drought resistance evaluation |
