【摘要】 铝(Al)毒是酸性土壤植物生长最重要的限制因子之一。NH4+-N和NO3--N作为最主要的无机氮源,在调控植物根际及体内生理生化反应过程中起到不同的作用。以2种主要形态氮的不同配比为氮源,分别进行3 d和14 d的培养,以探讨不同氮形态对Al毒的缓解作用。结果表明:在培养3 d试验中,NO3--N和NH4+-N处理组的相对根伸长量无明显差异;不同处理根尖内Al的积累量是:+Al+NH4+-N>+Al>+Al+NO3--N。培养14 d试验中,以NO3--N为主要氮源的处理组,其根和地上部的生物量均高于NH4+-N组。+Al+NO3--N处理组根系比+Al+NH4+-N处理组含有并分泌更多的柠檬酸,根内Al积累量与培养3 d试验规律相同。综合上述结果,研究认为NO3--N对大豆Al毒的缓解起到更积极的作用。更多还原

【Abstract】 Aluminum(Al) toxicity is one of the most important constraints limiting plant growth in acid soils.The main inorganic nitrogen forms NH4+-N and NO3--N have different functions in regulating the rhzisphere pH and some physiological processes of plants,which might have important effect on Al phytotoxicity.To evaluate the effects of NH4+-N and NO3--N on the occurring of Al toxicity in soybean,different ratio of NH4+-N and NO3--N were used to test the Al toxic effects on root elongation in 3-days experiments.The results were as follows: there were no significant difference in Al-induced relative root elongation inhibition with NO3--N and NH4+-N treatments.The sequence of Al accumulation in various treatments was as follows: +Al+ NH4+-N >+Al>+Al+ NO3--N.In the 14 d experiment,the biomass of both the roots and the shoots in the treatment of NO3--N as main nitrogen source were higher than those of NH4+-N as main source treatment.And more citrate secretion and citrate content were found in the roots of +Al+ NO3--N treatment than those treatment of +Al +NH4+-N.Less Al content was also found in the former treatment.Combined the results of 3 d and 14 d experiment,it is suggestted that NO3--N was better in alleviating the Al toxicity in soybean.更多还原