土壤酸胁迫对2种植物生长及镉富集的影响

Effects of Soil Acid Stress on the Growth and Cadmium Accumulation of Two Plants

[目的]探讨土壤酸化对植物生长及镉(Cd)富集能力的影响。[方法]以多年生黑麦草和蒲公英为研究对象,采用盆栽试验设置pH为3.0、4.5和5.5的3个梯度土壤,研究土壤酸胁迫对2种植物种子萌发、植物生长生理和Cd富集能力的影响。[结果]当土壤pH为3.0时,多年生黑麦草和蒲公英种子不能正常萌发和生长,而较低浓度的酸胁迫(pH 5.5)对多年生黑麦草种子发芽指数具有促进作用。当土壤pH由5.5下降到4.5时,多年生黑麦草和蒲公英的株高显著降低,根系长度显著增加,生物量无显著变化,且生长良好,叶绿素含量显著增加,表明这2种植物在较高浓度的酸胁迫时仍保持较强的耐性。当土壤pH由5.5降低至4.5时,多年生黑麦草对Cd的富集能力显著降低,而蒲公英对Cd的富集能力显著增强。2种植物根部对Cd的富集能力大于地上部的富集能力。[结论]多年生黑麦草和蒲公英在土壤pH为4.5和5.5条件下仍然能够生长良好,但2种植物在酸胁迫下对Cd的富集能力表现出明显差异。

[Objective]This study was to investigate the effect of soil acidification on plant growth and Cd accumulation.[Method]Lolium perenne and Taraxacum mongolicum were used as the research objects,three acid gradients with soil pH of 3.0,4.5 and 5.5 were designed by pot experiment to study the effects of soil acid stress on seed germination,plant growth physiology and Cd accumulation ability of two plants.[Result]Lolium perenne and Taraxacum mongolicum could not germinate and grow normally at soil pH of 3.0,while the lower concentration of acid stress(pH 5.5)could promote seed germination index of Lolium perenne.When the soil pH decreased from 5.5 to 4.5,the plant height of perennial ryegrass and dandelion were significantly reduced,the root length was significantly increased,there was no significant change in biomass,and the growth was good,and the chlorophyll content was significantly increased,indicating that these two plants still maintained strong tolerance under high concentration of acid stress.When the soil pH decreased from 5.5 to 4.5,the Cd accumulation ability of Lolium perenne decreased significantly,while that of Taraxacum mongolicum increased significantly.The Cd accumulation ability of the roots was greater than that of the shoots.[Conclusion]Lolium perenne and Taraxacum mongolicum can still grow well at soil pH 4.5 and 5.5,but the two plants show significant differences in Cd accumulation ability under acid stress.