Interactions between nitric oxide and plant hormones in aluminum tolerance

the adaptation to Al stress in plants. However, the mechanism by which NO and plant hormones interplay to improve Al tolerance are still unclear. We have recently shown that patterns of plant hormones alteration differ between rye and wheat under Al stress. NO may enhance Al tolerance by regulating hormonal equilibrium in plants, as a regulator of plant hormones signaling. In this paper, some unsolved issues are discussed based on recent studies and the complex network of NO and plant hormones in inducing Al tolerance of plants are proposed. Aluminum (Al) toxicity is a major limiting factor for crop pro-duction in acid soil, accounting for 30–50 % of the world’s arable lands. The root elongation growth in plants exposure to Al is rapidly inhibited. Plant species have evolved diverse mechanisms of Al tolerance including external exclusion and internal chela