| Title: | Role of Stomatal Conductance in Modifying the Dose Response of Stress-Volatile Emissions in Methyl Jasmonate Treated Leaves of Cucumber (Cucumis sativa) |
| Author(s): | Jiang Y; Ye J; Rasulov B; Niinemets U; |
| Address: | "Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia. College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China. Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia" |
| ISSN/ISBN: | 1422-0067 (Electronic) 1422-0067 (Linking) |
| Abstract: | "Treatment by volatile plant hormone methyl jasmonate (MeJA) leads to release of methanol and volatiles of lipoxygenase pathway (LOX volatiles) in a dose-dependent manner, but how the dose dependence is affected by stomatal openness is poorly known. We studied the rapid (0-60 min after treatment) response of stomatal conductance (G(s)), net assimilation rate (A), and LOX and methanol emissions to varying MeJA concentrations (0.2-50 mM) in cucumber (Cucumis sativus) leaves with partly open stomata and in leaves with reduced G(s) due to drought and darkness. Exposure to MeJA led to initial opening of stomata due to an osmotic shock, followed by MeJA concentration-dependent reduction in G(s), whereas A initially decreased, followed by recovery for lower MeJA concentrations and time-dependent decline for higher MeJA concentrations. Methanol and LOX emissions were elicited in a MeJA concentration-dependent manner, whereas the peak methanol emissions (15-20 min after MeJA application) preceded LOX emissions (20-60 min after application). Furthermore, peak methanol emissions occurred earlier in treatments with higher MeJA concentration, while the opposite was observed for LOX emissions. This difference reflected the circumstance where the rise of methanol release partly coincided with MeJA-dependent stomatal opening, while stronger stomatal closure at higher MeJA concentrations progressively delayed peak LOX emissions. We further observed that drought-dependent reduction in G(s) ameliorated MeJA effects on foliage physiological characteristics, underscoring that MeJA primarily penetrates through the stomata. However, despite reduced G(s), dark pretreatment amplified stress-volatile release upon MeJA treatment, suggesting that increased leaf oxidative status due to sudden illumination can potentiate the MeJA response. Taken together, these results collectively demonstrate that the MeJA dose response of volatile emission is controlled by stomata that alter MeJA uptake and volatile release kinetics and by leaf oxidative status in a complex manner" |
| Keywords: | Acetates/*pharmacology Cucumis sativus/*drug effects/metabolism/*physiology Cyclopentanes/*pharmacology Methanol/pharmacology Osmosis/drug effects Oxidation-Reduction/drug effects Oxylipins/*pharmacology Plant Growth Regulators/metabolism Plant Leaves/dru; |
| Notes: | "MedlineJiang, Yifan Ye, Jiayan Rasulov, Bahtijor Niinemets, Ulo eng Centre of Excellence EcolChange/European Regional Development Fund/ advanced grant 322603, SIP-VOL+/European Commission through the European Research Council/ Switzerland 2020/02/09 Int J Mol Sci. 2020 Feb 4; 21(3):1018. doi: 10.3390/ijms21031018" |
