复合盐碱胁迫对燕麦种子发芽的影响

Effects of complex salt-alkali stresses on seed germination of oat

为明确复合盐碱胁迫对燕麦(Avena sativa)种子发芽的影响,将中性盐NaCl、Na2SO4与碱性盐NaHCO3、Na2CO3按不同比例混合,依照碱浓度逐渐增加的原则分为6个胁迫处理组,每组设定6种不同盐浓度,来测定36种复合盐碱胁迫条件下燕麦种子的发芽率、发芽势、胚根与胚芽长等生长指标。结果表明,在各胁迫处理组下,燕麦种子的发芽率与发芽势均随着盐浓度的增加而下降,且碱性盐比例越大下降越明显。在最高浓度胁迫下(144mmol·L-1),无碱性盐存在的胁迫组燕麦种子发芽率为25.6%,碱性盐比例最低的胁迫组为11.1%,其余各组处理则均为0。胚根与胚芽生长表现出与发芽率相似的变化规律,且胚根对胁迫更敏感。对各胁迫因素与发芽指标进行逐步回归分析,发现在众多胁迫因素中,盐浓度起主要作用。由于植物在种子发芽阶段主要受水分的控制,而在复合盐碱胁迫下,水势主要由盐浓度决定,因此,盐浓度是复合盐碱胁迫下燕麦种子发芽的决定性因素。

In order to explore the effects of complex salt-alkali stresses on seed germination of Oat （Avena sativa）, six alkali concentration treatments with six levels of salinity each, and in total 36 kinds of salt-alkali conditions were simulated by mixing neutral salts （NaCl and Na2SO4） and alkaline salts （NaHCO3 and Na2CO3） in various proportions. Germination percentage, germination energy, radicle and shoot length were measured. The results showed that, germination percentage and germination energy both decreased with increasing salinity under all alkali treatments, and the salinity inhibit effects increased as alkali concentration increased. When subjected to the highest salinity （144 mmol·L-1）, germination percentage was 25.6%, 11.1%, 0, 0, 0 and 0, respectively, as alkaline salts proportion increased from 0 to 100%. Radicle and shoot length had the similar downtrends with germination index, and radicle growth was more sensitive to salinity stress. Stepwise regression analysis showed that, salinity was the dominant stress factor affecting seed germination. This may attribute to osmotic stress which mainly determined by sodium concentration in present study.