外源硅对不同程度盐胁迫下甘草种子萌发和幼苗生长发育的影响

目的 通过室内水培试验研究硅对不同程度盐胁迫下甘草种子萌发出苗和幼苗生长发育的影响效应。方法 盐胁迫设置轻度（50 mmol/L）、中度（100 mmol/L）和重度（150 mmol/L）3个梯度，硅源采用K₂SiO₃，硅处理浓度设置0、1、2、4、6、8 mmol/L共6个梯度，共计18个处理，同时设置蒸馏水为对照（CK）。结果 轻度和中度盐胁迫下，较低浓度的硅对甘草种子发芽率、发芽指数、出苗率和幼苗胚根长度没有显著影响，但对株高、根干质量、芽干质量和幼苗活力指数均有显著的促进作用；而高浓度的硅对种子萌发出苗和幼苗生长均具有显著抑制作用。在重度盐胁迫下，较低浓度的外源硅对甘草种子发芽出苗（发芽率、出苗率、发芽指数、幼苗活力指数）及幼苗生长（胚根长度和质量、胚芽长度和质量）均有显著的促进作用，但高浓度的外源硅对甘草幼苗生长有显著的抑制作用。结论 硅至少直接参与了甘草种子萌发出苗和幼苗生长的生理生化过程，且对甘草的盐害有一定的缓解作用，这种缓解作用强度因盐胁迫程度和硅浓度而异。

Effects of silicon addition on seed germination and seedling growth of Glvarrhiza uralensis under salt stress

Objective In this study, a water culture experiment was conducted to investigate the effects of silicon addition on the seed germination and seedling growth of Glvarrhiza uralensis under salt stress. Methods Various components of the experiment were three salt treatments (50, 100, and 150 mmol/L NaCl) and six Si levels (0, 1, 2, 4, 6, and 8 mmol/L) in distilled water. Potassium silicate (K₂SO₄) was used as a source of Si. Results The result showed that silicon addition had the significant effect on the seed germination and seedling growth, and this effect was dependent on the salt stress level and silicon addition concentration. Under 50 and 100 mmol/L NaCl stress condition, lower concentration silicon addition had no significant effect on the germination rate, germination index, seedling emergence rate, and radical length, while had the significantly promoted effect on plant height, and root and shoot dry weight of G. uralensis. However, higher concentration silicon addition had the significantly inhibited effect on the seed germination and seedling growth. Under 150 mmol/L NaCl stress condition, silicon addition at lower concentration significantly promoted the seed germination and seedling growth of G. uralensis, including the germination rate, seedling emergence, germination index, seedling vigor, radical and embryo length, and root and shoot dry weight. However, silicon addition at higher concentration significantly inhibited the seedling growth of G. uralensis, while had no significant effect on the seed germination. Conclusion Silicon is directly involved in the physiological process of the seed germination and seedling growth of G. uralensis under salt stress condition, and this involved extent is dependent on the salt stress level and silicon addition concentration.