Role of guard cell metabolism and mesophyll-derived metabolites on stomatal movement regulation in angiosperm and fern models

• Ano de defesa: 2020
• Autor(a) principal: Cândido Sobrinho, Silvio Alencar
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Palavras-chave em Português: controle estomático; evolução estomática; metabolômica
• Link de acesso: http://www.repositorio.ufc.br/handle/riufc/52158

Plants use water in many physiological processes such as in metabolic reactions, sap conduction through vessels and heat quenching through transpiration. Stomata, structures mainly found at the leaf epidermis, are the main inlet of CO2 for photosynthesis and outlet of water, being thus key regulators of plant water use efficiency. Combined environmental and endogenous stimuli regulate stomatal movements by changes in the metabolismo of guard cells. However, it remains nuclear how such mechanisms of stomatal regulation have developed as evolutive traits. This research, divided in two chapters, consists in a literature review of guard cell metabolism (Chapter I), and the investigation of which metabolites and metabolic pathways are involved on stomatal movement regulation in angiosperms and ferns (Chapter II). This later, started the research from a meta-analysis of gas enchange and metabolomics data available in literature. Further, the metabolites glutamate, malate sucrose were chosen to investigate the response ons tomatal dynamics in cowpea bean, and two fern species under exogenous application of these metabolites. Abcisic acid (ABA) and mannitol, this later used as na osmotic control were also used. Results demonstrate fern species used in this study did not show significant changes on stomatal conductance (gs) using ABA, whilst a drastic reduction has been observed in angiosperms using this phytohormone. The application of exogenous malate and sucrose induced the stomatal closure in all species, however at higher intensity and velocity in angiosperm. This results suggest lesser gs intensity and velocity observed in ferns, may be due changes on stomatal responses to metabolites driven from mesophyll cells. Thus, the results suggest angiosperms possess differential mechanisms which increase sensitivity to ABA and of the increased contribution of mesophyll-driven metabolites to velocity of stomatal responses in angioperms.