title: Hormone cross-talk during seed germination.
abstract: Hormones are chemical substances that can affect many cellular and developmental processes at low concentrations. Plant hormones co-ordinate growth and development at almost all stages of the plant's life cycle by integrating endogenous signals and environmental cues. Much debate in hormone biology revolves around specificity and redundancy of hormone signalling. Genetic and molecular studies have shown that these small molecules can affect a given process through a signalling pathway that is specific for each hormone. However, classical physiological and genetic studies have also demonstrated that the same biological process can be regulated by many hormones through independent pathways (co-regulation) or shared pathways (cross-talk or cross-regulation). Interactions between hormone pathways are spatiotemporally controlled and thus can vary depending on the stage of development or the organ being considered. In this chapter we discuss interactions between abscisic acid, gibberellic acid and ethylene in the regulation of seed germination as an example of hormone cross-talk. We also consider hormone interactions in response to environmental signals, in particular light and temperature. We focus our discussion on the model plant Arabidopsis thaliana.
authors.affiliation: Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M1C 1A4, Canada gazzarrini@utsc.utoronto.ca.
authors.forename: Sonia
authors.initials: S
authors.lastname: Gazzarrini
authors.affiliation: Department of Biological Sciences and Department of Cell and Systems Biology, University of Toronto, Toronto, ON, M1C 1A4, Canada gazzarrini@utsc.utoronto.ca.
authors.forename: Allen Yi-Lun
authors.initials: AY
authors.lastname: Tsai
mesh_terms: D005030:Ethylenes / Q000096:biosynthesis; D018525:Germination; D008027:Light; D010937:Plant Growth Regulators / Q000378:metabolism*; D012639:Seeds / Q000254:growth & development*; D015398:Signal Transduction; D013696:Temperature
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; C036216:ethylene
keywords: abscisic acid; dormancy; ethylene; germination; gibberellic acid; hormone cross-talk; light; temperature