title: Aluminium-induced reduction of plant growth in alfalfa (Medicago sativa) is mediated by interrupting auxin transport and accumulation in roots.
abstract: The objective of this study was to investigate Al(3+)-induced IAA transport, distribution, and the relation of these two processes to Al(3+)-inhibition of root growth in alfalfa. Alfalfa seedlings with or without apical buds were exposed to 0 or 100 μM AlCl3 and were foliar sprayed with water or 6 mg L(-1) IAA. Aluminium stress resulted in disordered arrangement of cells, deformed cell shapes, altered cell structure, and a shorter length of the meristematic zone in root tips. Aluminium stress significantly decreased the IAA concentration in apical buds and root tips. The distribution of IAA fluorescence signals in root tips was disturbed, and the IAA transportation from shoot base to root tip was inhibited. The highest intensity of fluorescence signals was detected in the apical meristematic zone. Exogenous application of IAA markedly alleviated the Al(3+)-induced inhibition of root growth by increasing IAA accumulation and recovering the damaged cell structure in root tips. In addition, Al(3+) stress up-regulated expression of AUX1 and PIN2 genes. These results indicate that Al(3+)-induced reduction of root growth could be associated with the inhibitions of IAA synthesis in apical buds and IAA transportation in roots, as well as the imbalance of IAA distribution in root tips.
authors.affiliation: School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
authors.forename: Shengyin
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Ren
authors.affiliation: Department of Plant Biology and Pathology, Rutgers, The State University of New Jersey, New Jersey, NJ 08901, USA.
authors.forename: Bingru
authors.initials: B
authors.lastname: Huang
authors.affiliation: Instrumental Analysis Centre of Shanghai Jiao Tong University, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
authors.forename: Ge
authors.initials: G
authors.lastname: Wang
authors.affiliation: School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.affiliation: School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.|Key Laboratory of Urban Agriculture (South), Ministry of Agriculture, Shanghai 201101, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: An
mesh_terms: D000535:Aluminum / Q000633:toxicity*; D001692:Biological Transport / Q000187:drug effects; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors*; D000455:Medicago sativa / Q000187:drug effects* / Q000254:growth & development*; D010937:Plant Growth Regulators / Q000037:antagonists & inhibitors*; D018517:Plant Roots / Q000187:drug effects* / Q000254:growth & development*; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D000535:Aluminum