可降解螯合剂对草坪植物高羊茅发育及生理的影响

Effects of Biodegradable Chelator on Growth and Physiology of Festuca arundinacea Seedlings

以盆栽高羊茅为试验材料,研究了土壤中添加不同浓度(3、6、9、12和15 mmol·kg^(-1))生物可降解螯合剂谷氨酸二乙酸四钠(Glutamic acid N,N-diacetic acid tetra sodium salt,GLDA)和亚氨基二琥珀酸四钠盐(Iminodisuccinic acid sodium salt,IDS)处理对种子萌发和幼苗发育及生理的影响。结果表明,GLDA和IDS处理对高羊茅种子萌发有一定的抑制作用,并且高浓度的抑制作用更强。对高羊茅地上生物量的影响表现为低浓度促进,高浓度抑制,6 mmol·kg^(-1)处理生物量达到最大;而所有螯合剂处理均显著抑制了根系的生长。与对照相比,低浓度的螯合剂(3、6和9 mmol·kg^(-1))对叶绿素和类胡萝卜素含量没有显著影响,但高浓度处理显著降低了其含量。螯合剂对SOD和CAT活性的影响呈现先增加后降低的趋势,而POD活性和MDA含量则随螯合剂浓度的增加而升高,表明添加螯合剂对高羊茅构成了逆境胁迫。鉴于此,在两种螯合剂应用于土壤重金属修复时,以低浓度(6 mmol·kg^(-1))施加为宜,并且可以考虑在植物收获前几天施加或分次加入。

Pot experiment was conducted to investigate the effects of biodegradable chelators–Glutamic acid N, N-diacetic acid tetra sodium salt（GLDA）and iminodisuccinic acid sodium salt（IDS）added at different concentrations（3,6,9,12 and 15 mmol · kg^（-1））on seed germination,growth and physiology of Festuca arundinacea Schreb. seedlings. The results showed that the addition of GLDA and IDS inhibited seed germination of F. arundinacea,especially at high concentrations. The addition of GLDA and IDS at low concentrations increased aboveground biomass, but reduced it at high concentrations. The highest aboveground biomass was found at the chelator treatment of 6 mmol · kg^（-1）,which was significantly higher than those in the other chelator treatments. The addition of GLDA and IDS inhibited root growth of F. arundinacea,especially at high concentrations. Compared with the control,chelators at low concentrations（3,6 and 9 mmol · kg^（-1））had no significant effects on chlorophyll and carotenoid contents. However,chelators at high concentrations significantly decreased chlorophyll and carotenoid contents. The activities of SOD and CAT increased and then decreased with the increase in chelator concentration,while the POD activity and MDA content increased constantly with the increase in chelator dosage. The results indicated that the addition of GLDA and IDS may form stress for F. arundinacea,and the plants could develop resistance to the stress by increasing the activities of antioxidant enzymes. Thus,when GLDA and IDS are applied in remediation of soil polluted by heavy metals,they should be applied at a low concentration（6 mmol · kg^（-1））and should be added several days before plants are harvested or added at a low dosage in multiple times.