title: Physiological characterization of maize tolerance to low dose of aluminum, highlighted by promoted leaf growth.
abstract: Effects of a low aluminum (Al) dose were characterized. The Al supplement inhibited root growth but enhanced leaf growth in maize lines with different Al sensitivities. High levels of Al are phytotoxic especially in acidic soils. The beneficial effects of low Al levels have been reported in some plant species, but not in maize. Maize is relatively more sensitive to Al toxicity than other cereals. Seedlings, at the three leaf stage, of four Chinese maize foundation parent inbred lines with different Al tolerances, were exposed to complete Hoagland's nutrient solution at pH 4.5 supplemented with 48 μM Al(3+) under controlled growth conditions, and then the Al stress (AS) was removed. The leaf and root growth, root cell viability, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ions (K(+), Ca(++) and Mg(++)), photosynthetic rate and chlorophyll, protein and malondialdehyde contents in tissues were assayed. In conclusion, a low Al dose inhibits root growth but enhances leaf growth in maize. The Al-promoted leaf growth is likely a result of increased protein synthesis, a lowered Ca(++) level, and the discharge of the growth-inhibitory factors. The Al-promoted leaf growth may be a 'memory' effect caused by the earlier AS in maize. Al causes cell wall rupture, and a loss of K(+), Ca(++) and Mg(++) from root cells. CAT is an auxiliary antioxidant enzyme that works selectively with either SOD or POD against AS-related peroxidation, depending on the maize tissue. CAT is a major antioxidant enzyme responsible for root growth, but SOD is important for leaf growth during AS and after its removal. Our results contribute to understanding how low levels of Al affect maize and Al-resistant mechanisms in maize.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China.
authors.forename: Liang
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China.
authors.forename: Xian-Wei
authors.initials: XW
authors.lastname: Fan
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China.
authors.forename: Jian-Long
authors.initials: JL
authors.lastname: Pan
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China.
authors.forename: Zhang-Bao
authors.initials: ZB
authors.lastname: Huang
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Key Laboratory of Ministry of Education for Microbial and Plant Genetic Engineering, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, People's Republic of China. dyzl@gxu.edu.cn.
authors.forename: You-Zhi
authors.initials: YZ
authors.lastname: Li
mesh_terms: D000535:Aluminum / Q000494:pharmacology*; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D018977:Micronutrients / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects* / Q000254:growth & development; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development; D013482:Superoxide Dismutase / Q000378:metabolism; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000975:Antioxidants; D018977:Micronutrients; D008315:Malondialdehyde; D000535:Aluminum; D002374:Catalase; D013482:Superoxide Dismutase
keywords: Acidic soils; Aluminum benefit; Aluminum toxicity; Maize; Root