入侵植物节节麦种子萌发及幼苗生长对盐碱胁迫的响应

Seed germination and seedling growth responses of invasive alien plant Aegilops tauschii to saline-alkali stress

【目的】节节麦入侵已严重威胁到我国小麦的安全生产,探明节节麦对盐碱生境的适应能力,为节节麦入侵扩散的进一步预测提供参考。【方法】研究了不同浓度[0(CK)、50、100、150和200 mmol/L]NaCl和Na2CO3胁迫对节节麦种子萌发及幼苗生长的影响。【结果】①随着两种盐处理液浓度的增加,节节麦种子发芽率、胚芽及胚根长度均呈持续下降的变化。当处理液分别达到150及100 mmol/L时,NaCl和Na2CO3胁迫中节节麦种子发芽率与CK差异显著,至200 mmol/L时,Na2CO3处理的种子不发芽。此外,相同浓度条件下,Na2CO3胁迫中发芽和生长指标均明显低于NaCl处理;②盐碱胁迫中,随处理液浓度的增加,节节麦脯氨酸含量和SOD活性呈显著增加的变化,而相对电导率和MDA含量在低浓度盐碱处理中较CK增加不显著,之后在高浓度的处理中则呈急剧增加的变化。由此表明,节节麦能够通过自身调节适应一定范围的盐碱胁迫。此外,相同盐处理浓度条件下,Na2CO3处理的上述指标均明显高于NaCl处理。【结论】综合分析表明,节节麦对盐碱生境具有一定的适应能力,而Na2CO3对其种子萌发及幼苗生长的抑制作用大于NaCl。

【Objective】Aegilops tauschiiCoss.invasion has seriously threatened the security of wheat production in China.In order to forecast theA.tauschiiinvasion risk, clarify the adaptability ofA.tauschiito saline-alkali habitats.【Method】The stress effects of NaCl and Na2CO3 at different concentrations [0(CK), 50, 100, 150 and 200 mmol/L]on seed germination and seedling growth ofA.tauschii. 【Result】Germination rate, and radicle and embryo lengths decreased continuously with an increase in the saline-alkali concentration.At concentrations of 150 and 100 mmol/L, thegermination rate decreased significantly in comparison with CK for the NaCl and Na2CO3 treatments, respectively.Noneof theA.tauschiiseeds germinated at a Na2CO3 concentration of 200 mmol/L.In addition, both the germination rate andseedling growth under Na2CO3 stress were significantly lower than those under NaCl stress at the same treatment concen-trations.The proline content and superoxide dismutase(SOD) activity increased significantly with an increase in concentration of the saline-alkali treatment solutions.However, the relative electric conductivity and malondialdehyde(MDA)content showed no significant increase at low concentrations of the saline-alkali treatments but increased sharply at high concentrations.This suggests thatA.tauschiican adapt biochemically to a certain range of saline-alkali stress through self-regulation.In addition, the values for these biochemical indexes under Na2CO3 stress were significantly higher thanunder NaCl stress at the same treatment concentrations. 【Conclusion】These results indicate thatA.tauschiihas a certainphysiological ability to adapt to saline-alkali habitats, and the effects of Na2CO3 stress on seed germination and seedlinggrowth were more significant than those of NaCl stress.