摘要
Abscisic acid （ABA） was originally identified in the early 1960s, and was thought to be involved in fruit and leaf ab- scission. Over the past 50 years, ABA was intensely studied and has become one of the vital plant hormones implicated in seed dormancy, seed germination, stomatal regulation, flowering, senescence and environmental stress responses. Early work isolated the mutants abil （ABA-insensitive 1） and abi2, which are insensitive to ABA [1]. These two genes were subsequently revealed to encode members of the clade A protein phosphatase 2Cs （PP2Cs） of serine/threonine pro- tein phosphatases （see review [2]）. Additional members of the clade A PP2Cs such as ABA-hypersensitive germinationl （AHG1） and AHG3, were also shown to participate in ABA stress signaling [2]. These PP2Cs function as negative regu- lators of ABA response.
Abscisic acid(ABA)was originally identified in the early1960s,and was thought to be involved in fruit and leaf abscission.Over the past 50 years,ABA was intensely studied and has become one of the vital plant hormones implicated in seed dormancy,seed germination,stomatal regulation,flowering,senescence and environmental stress responses.
