温度、NaCl及PEG胁迫对沙生木地肤种子萌发和幼苗生长的影响

Effect of Temperature,NaCl and PEG Stress on Germination and Seedling Growth of Kochiaprostrata(L.)Schrad.var.horxina D.S.Wen

以沙生木地肤种子为材料,置于不同变温,不同NaCl和PEG-6000浓度下进行萌发试验,探讨温度、盐胁迫和干旱胁迫对其发芽率和幼苗生长的影响。结果表明:沙生木地肤种子萌发的适宜温度为25℃/15℃,发芽率为(92±3.27)%,但与20℃/10℃和15℃/5℃下发芽率无显著差异,过高温或过低温周期对种子的萌发和幼苗生长具有抑制作用。低浓度的NaCl溶液(≤0.2mol/L)对种子的初始发芽率和最终发芽率没有显著影响,随着NaCl浓度的增加,种子的发芽率和幼苗生长高度整体呈下降趋势,种子的初始发芽时间逐渐推后,NaCl浓度>1.0mol/L,种子仍能萌发,但幼苗生长基本停止;PEG胁迫下,沙生木地肤种子表现出较好的抗旱性,渗透势≥-1.0MPa下,PEG胁迫对种子的萌发抑制作用不明显,渗透势降低到-1.6MPa时,发芽率仍高于40%,萌发幼苗仍能缓慢生长。

In this research,Kochiaprostrata（L.）Schrad.var.horxina D.S.Wen was selected to study the effect on germination rate and seedling growth of different temperature,NaCl and PEG.The main results were as follows：The suitable temperature for germination of Kochiaprostrata（L.）Schrad.var.horxina D.S.Wen seed was 25℃/15℃,the germination percentage was（92±3.27）%,and no significantly differences for germination with the 20℃/10℃ and 15℃/5℃,low temperature and high temperature inhibited seed germination and seedling growth.Low concentration of NaCl（≤0.2mol/L）had no effect for the germination and seedling growth,seed germination rate and seedling growth exhibits a downtrend and delayed initial germination time with the NaCl concentration increased,and the seedling did not grow in the concentration of NaCl was greater than 1.0mol/L.Kochiaprostrata（L.）Schrad.var.horxina D.S.Wen exhibits a more drought resistance under PEG stress,the seed germination and seedling growth had no significantly inhibited when the osmotic stress greater than or equal-1.0MPa,the germination rate was still higher than 40%in the osmotic potential reduced to-1.6MPa,in the same times,seedling still could grow.