沙埋、干旱及盐碱胁迫对苦豆子种子萌发的影响

Effects of Sand,Drought and Saline-alkali Stress on Seed Germination of Sophora alopecuroides

【目的】探究沙埋、干旱以及盐碱3种单因素胁迫如何影响苦豆子(Sophora alopecuroides)种子萌发特性,揭示3种胁迫在不同梯度变化下与苦豆子种子萌发特性的关系。【方法】以苦豆子为研究对象,首先将2种中性盐(NaCl、Na2SO4)和2种碱性盐(NaHCO3、Na2CO3)按一定摩尔比例分为A、B、C 3组进行混合,每组中碱性盐比例逐步提高,配置完成后,在每组处理内设置6个土壤含盐量水平,依次为:0(CK)、0.5%、1.0%、1.5%、2.0%、2.5%;干旱胁迫共设置5个梯度,按田间持水量百分比设置,分别为20%±5%、35%±5%、50%±5%、65%±5%、80%±5%;沙埋胁迫共设置4种沙埋深度,分别为0、2、4、6 cm。【结果】1)过深的沙埋会严重影响苦豆子种子萌发,6 cm的沙埋胁迫下无种子萌发,最适萌发条件为2 cm沙埋。2)干旱胁迫对苦豆子的发芽势有显著影响,但对发芽率和发芽指数无显著影响。3)中性、低碱性和高碱性3种盐碱类型对苦豆子萌发未见显著影响。4)苦豆子种子的发芽指数、发芽势和发芽率与沙埋深度和土壤含盐量呈显著负相关(P<0.05),但与土壤水分并无显著的相关性。【结论】苦豆子种子萌发受沙埋深度及土壤含盐量影响较大,沙埋深度以2 cm的轻度沙埋为宜,在水分条件较好的低盐碱土壤环境中苦豆子的种子萌发效果最佳。适当的胁迫条件能够对苦豆子种子萌发产生一定的积极作用,但需要注意合理控制胁迫程度,以期更好地发挥苦豆子作为生态修复植物所具有的生态和经济价值。

【Objective】To explore the effects of three single factors of sand burial,drought and saline-alkali stress on seed germination characteristics of Sophora alopecuroides,and to reveal the relationship between three kinds of stress and seed germination of S.alopecuroides under different gradient changes.【Method】Taking S.alopecuroides as the research object,two neutral salts,NaCl and Na2SO4,and two basic salts,NaHCO3 and Na2CO3,were divided into A,B and C groups for mixing according to a certain molar ratio,and the proportion of alkaline salt in each group was gradually increased.After the configuration,six soil salt levels were set in each group,which were successively:0(CK),0.5%,1.0%,1.5%,2.0%,2.5%;Five gradients of drought stress were set according to the percentage of field capacity,which were 20%±5%,35%±5%,50%±5%,65%±5%and 80%±5%,respectively.Four kinds of sand depth were set in the sand burial test,which were 0,2,4 and 6 cm respectively.【Results】1)Too deep sand burial depth would seriously affect seed germination of S.alopecuroides.Under sand burial stress of 6 cm,no seedling germination occurred,and the optimal germination condition was 2 cm sand burial.2)Drought stress had significant effects on germination energy of S.alopecuroides(P<0.05),but had no significant effects on germination percentage and germination index.3)There was no significant effect on the germination of S.alopecuroides by the three types of saline-alkali stress:neutral,low alkaline and high alkaline.4)The germination index,germination energy and germination percentage of S.alopecuroides seeds were negatively correlated with sand burial stress and soil salt content(P<0.05),but there was no significant correlation between soil moisture and the above three indexes.【Conclusion】The seed germination of S.alopecuroides was greatly affected by sand burial depth and soil salt content,sand burial depth of 2 cm is appropriate,the seed germination effect of S.alopecuroides was the best in low saline soil with good water condition.Appropriate stress conditions could play a positive role in seed germination of S.alopecuroides.In order to make better use of the ecological and economic value of S.alopecuroides as a restorative plant,attention should be paid to properly controlling the degree of stress.