入侵植物节节麦种子萌发及幼苗生长对盐碱胁迫的响应

【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。

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

【Objective】Aegilops tauschii Coss. invasion has seriously threatened the security of wheat production in China. In order to forecast the A. tauschii invasion risk, clarify the adaptability of A. tauschii to 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 of A. 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, the germination rate decreased significantly in comparison with CK for the NaCl and Na₂CO₃ treatments, respectively. None of the A. tauschii seeds germinated at a Na₂CO₃ concentration of 200 mmol/L. In addition, both the germination rate and seedling growth under Na₂CO₃ stress were significantly lower than those under NaCl stress at the same treatment concentrations. 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 that A. tauschii can 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 than under NaCl stress at the same treatment concentrations. 【Conclusion】These results indicate that A. tauschii has a certain physiological ability to adapt to saline-alkali habitats, and the effects of Na₂CO₃ stress on seed germination and seedling growth were more significant than those of NaCl stress.