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Exogenous abscisic acid alleviates zinc uptake and accumulation in P opulus × canescens exposed to excess zinc
Author(s) -
SHI WENGUANG,
LI HONG,
LIU TONGXIAN,
POLLE ANDREA,
PENG CHANGHUI,
LUO ZHIBIN
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12434
Subject(s) - abscisic acid , salicylic acid , gibberellin , chemistry , zinc , auxin , shoot , photosynthesis , cadmium , glutathione , endogeny , biochemistry , botany , biology , gene , enzyme , organic chemistry
Abstract A greenhouse experiment was conducted to study whether exogenous abscisic acid ( ABA ) mediates the responses of poplars to excess zinc ( Z n). P opulus × canescens seedlings were treated with either basal or excess Z n levels and either 0 or 10 μ m ABA . Excess Z n led to reduced photosynthetic rates, increased Z n accumulation, induced foliar ABA and salicylic acid ( SA ), decreased foliar gibberellin ( GA 3 ) and auxin ( IAA ), elevated root H 2 O 2 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 Z n concentrations with 7 d treatments, it increased levels of endogenous ABA , GA 3 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 Z n 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 Z n but repressed by exogenous ABA application. These results suggest that exogenous ABA can decrease Z n concentrations in P . × canescens under excess Z n for 7 d, likely by modulating the transcript levels of key genes involved in Z n uptake and detoxification.