Impacts of plant hormones on controlling stomatal conductance
Date
2024-02-21
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Abstract
Eluks ja kohanemiseks pidevalt muutuvas keskkonnas peavad taimed ära tundma mitmesuguseid stiimuleid ja vajadusel tagama kaitsemehhanismide kiire aktiveerumise. Taimedele põhjustavad stressi põud, kuiv õhk, temperatuuri äärmused, õhusaaste, patogeenide rünnakud jne. Õhulõhed, taime lehtedes asuvad mikroskoopilised poorid, on olulised taime kohanemisel keskkonnatingimustega, sest tasakaalustavad süsihappegaasi omastamist fotosünteesiks ja vee aurumist taimedest. Õhulõhede avanemist või sulgumist põhjustavad muutused valgustingimustes, õhuniiskuses ja süsihappegaasi tasemes, samuti sulguvad õhulõhed kokkupuutel osooni või patogeenidega. Lisaks reageerivad õhulõhed ka mitmesugustele endogeensetele stiimulitele, seal hulgas väikestes kogustes toimivatele taimehormoonidele. Abstsiishape (ABA) on taimehormoon, millel on oluline roll õhulõhede sulgumises ja põuakindluse kujunemises. Samal ajal on ebaselge, kuidas teised taimehormoonid õhulõhede käitumist mõjutavad. Oma uuringus kasutasime geneetilist lähenemist ja gaasivahetuse mõõtmisi erinevates tingimustes, et mõista taimehormoonide jasmoonhappe, salitsüülhappe, etüleeni ja strigolaktoonide rolli kogu taime õhulõhede juhtivuse reguleerimisel. Leidsime, et kuigi jasmoonhape, salitsüülhape ja etüleen mõjutavad õhulõhede juhtivust oluliselt vähem kui ABA, moduleerivad need hormoonid õhulõhede reageerimist mõningatele keskkonnateguritele ja ABA-le Lisaks näitasime ka, et strigolaktoonid kontrollivad õhulõhede juhtivust ABA-st sõltumatult. Meie tulemused näitavad erinevate hormoonide mõju õhulõhede juhtivusele ja reaktsioonivõimele, laiendades meie arusaama õhulõhede regulatsioonist pidevalt muutuvas keskkonnas.
To survive and adapt to the ever-changing environment, plants must recognize various stimuli and ensure the rapid activation of corresponding protective mechanisms. The list of biotic and abiotic stresses influencing plants includes drought, dry air, temperature extremes, air pollutants, pathogen attacks, etc. Stomata, microscopic pores on plant surfaces, constitute one of the central points in plant adaptation to environmental conditions as they balance CO2 uptake for photosynthesis with the evaporation of water from plants. Stomatal opening and closure can be initiated by changes in illumination conditions, air humidity, and CO2 levels, as well as by an exposure to ozone or a pathogen attack. In addition, stomata also react to a number of endogenous stimuli, including phytohormones acting in minute concentrations. Thus, abscisic acid (ABA) is a plant hormone well-known for its involvement in drought resistance and promoting stomatal closure. At the same time, stomatal regulation by other phytohormones is significantly less understood. In our study, we used a genetic approach and gas exchange measurements under various conditions to compare the roles of jasmonic acid, salicylic acid, ethylene, and strigolactones in controlling whole-plant stomatal conductance. We found that, although jasmonic acid, salicylic acid, and ethylene influence steady-state stomatal conductance significantly less than ABA, stomatal responsiveness to some environmental stimuli and ABA can be modulated by these hormones. Furthermore, we also showed that strigolactones control stomatal conductance independently of ABA. Our results demonstrate the impacts of various hormones on controlling stomatal conductance and stomatal reactions to environmental cues, expanding our understanding of stomatal regulation under ever-changing environmental conditions.
To survive and adapt to the ever-changing environment, plants must recognize various stimuli and ensure the rapid activation of corresponding protective mechanisms. The list of biotic and abiotic stresses influencing plants includes drought, dry air, temperature extremes, air pollutants, pathogen attacks, etc. Stomata, microscopic pores on plant surfaces, constitute one of the central points in plant adaptation to environmental conditions as they balance CO2 uptake for photosynthesis with the evaporation of water from plants. Stomatal opening and closure can be initiated by changes in illumination conditions, air humidity, and CO2 levels, as well as by an exposure to ozone or a pathogen attack. In addition, stomata also react to a number of endogenous stimuli, including phytohormones acting in minute concentrations. Thus, abscisic acid (ABA) is a plant hormone well-known for its involvement in drought resistance and promoting stomatal closure. At the same time, stomatal regulation by other phytohormones is significantly less understood. In our study, we used a genetic approach and gas exchange measurements under various conditions to compare the roles of jasmonic acid, salicylic acid, ethylene, and strigolactones in controlling whole-plant stomatal conductance. We found that, although jasmonic acid, salicylic acid, and ethylene influence steady-state stomatal conductance significantly less than ABA, stomatal responsiveness to some environmental stimuli and ABA can be modulated by these hormones. Furthermore, we also showed that strigolactones control stomatal conductance independently of ABA. Our results demonstrate the impacts of various hormones on controlling stomatal conductance and stomatal reactions to environmental cues, expanding our understanding of stomatal regulation under ever-changing environmental conditions.
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