title: Exogenous abscisic acid alleviates zinc uptake and accumulation in Populus × canescens exposed to excess zinc.
abstract: A greenhouse experiment was conducted to study whether exogenous abscisic acid (ABA) mediates the responses of poplars to excess zinc (Zn). Populus × canescens seedlings were treated with either basal or excess Zn levels and either 0 or 10 μm ABA. Excess Zn led to reduced photosynthetic rates, increased Zn accumulation, induced foliar ABA and salicylic acid (SA), decreased foliar gibberellin (GA3 ) and auxin (IAA), elevated root H2 O2 levels, and increased root ratios of glutathione (GSH) to GSSG and foliar ratios of ascorbate (ASC) to dehydroascorbate (DHA) in poplars. While exogenous ABA decreased foliar Zn concentrations with 7 d treatments, it increased levels of endogenous ABA, GA3 and SA in roots, and resulted in highly increased foliar ASC accumulation and ratios of ASC to DHA. The transcript levels of several genes involved in Zn uptake and detoxification, such as yellow stripe-like family protein 2 (YSL2) and plant cadmium resistance protein 2 (PCR2), were enhanced in poplar roots by excess Zn but repressed by exogenous ABA application. These results suggest that exogenous ABA can decrease Zn concentrations in P. × canescens under excess Zn for 7 d, likely by modulating the transcript levels of key genes involved in Zn uptake and detoxification.
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
authors.forename: Wen-Guang
authors.initials: WG
authors.lastname: Shi
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Tong-Xian
authors.initials: TX
authors.lastname: Liu
authors.forename: Andrea
authors.initials: A
authors.lastname: Polle
authors.forename: Chang-Hui
authors.initials: CH
authors.lastname: Peng
authors.forename: Zhi-Bin
authors.initials: ZB
authors.lastname: Luo
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000378:metabolism; D001673:Biodegradation, Environmental; D003683:Dehydroascorbic Acid / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D005875:Gibberellins; D005978:Glutathione / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D018384:Oxidative Stress; D010788:Photosynthesis; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D032107:Populus / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D014197:Trees; D015032:Zinc / Q000378:metabolism*
chemical_list: D005875:Gibberellins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D000040:Abscisic Acid; D005978:Glutathione; D015032:Zinc; D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid
keywords: heavy metals; oxidative stress; phytohormones; phytoremediation; transcriptional regulation