盐胁迫对超干处理苜蓿种子萌发及幼苗生长的影响

Germination and growth of ultra-dried alfalfa seeds under salt stress

以陇东苜蓿为材料,研究超干处理苜蓿种子在盐胁迫下的萌发和幼苗生长情况。将NaCl和Na2SO4按9∶1摩尔比混合,模拟典型盐胁迫环境,设置0,10,20,40,60和100 mmol/L 6个盐胁迫梯度,以未超干种子进行发芽试验并选择出最适盐胁迫浓度作为盆栽试验处理浓度。同时采用硅胶室温干燥法对种子进行不同时间的超干处理,将其含水量由最初的9.03%（CK,0 h）分别降至7.09%（12h）、6.93%（24 h）、6.36%（48 h）5、.72%（72 h）、5.46%（96 h）、5.18%（120 h）4、.97%（144 h）和4.59%（216 h）,并在所选梯度盐胁迫下进行盆栽沙培试验,观察超干处理后不同超干种子在特定浓度盐胁迫下的萌发与幼苗生长情况。结果显示40 mmol/L盐胁迫下,超干处理48-96 h（含水量6.36%-5.46%）,种子发芽率,发芽势和活力指数优于对照;超干处理72-120 h（含水量5.72%-5.18%）种子幼苗存活率和叶片数大于对照;超干处理96-144 h（含水量5.46%-4.97%）,幼苗株高显著高于对照。表明适当的超干处理（48-120 h,含水量6.36%-5.18%）可提高苜蓿种子和幼苗的抗盐能力。

Medicago sativa cv.Longdong was used as material to study the effect of salt stress on germination and seedling emergence of differently ultradried alfalfa seeds.NaCl and Na2SO4 were mixed at the mole ratio of 9 to 1 to imitate typical salt stress environment,and 6 salinities：0,10,20,40,60 and 100 mmol/L were used in germination experiment with un-ultradried alfalfa seeds to select the optimum salinity for the successive pot culture.Simultaneously,alfalfa seeds were dried with silica gel at different time periods to reduce the moisture contents of seeds to 7.09%（12 h）,6.93%（24 h）,6.36%（48 h）,5.72%（72 h）,5.46%（96 h）,5.18%（120 h）,4.97%（144 h）and 4.59%（216 h）,respectively,from the initial moisture content of 9.03%（CK,0 h）,and pot culture in sand was conducted at the selected salinity to observe the germination and seedling emergence of differently ultradried seeds.The result indicated that on condition of 40 mmol/L salt stress,sprouts derived from seeds ultra-dried between 48 and 96 h（moisture contents：6.36%～5.46%）performed better in seed germination rate,germination potential and vigor index;survival rate and leaf number of seedlings derived from seeds ultra-dried between 72 and 120 h（moisture contents：5.72%～5.18%）performed better than the control;and seedlings derived seeds ultra-dried between 96 and 144 h（moisture contents：5.46%～4.97%）performed better in shoot height,indicating that appropriate ultra-drying treatment（48～120 h,moisture contents：6.36%～5.18%） helps to increase salt-resistant capability of alfalfa seeds and seedlings.