Exogenous application of trehalose induced H2O2 production and stomatal closure in Vicia faba

Abstract

Trehalose can reduce stomatal aperture by a hydrogen-peroxide-dependent pathway in Vicia faba L. (cv. Daqingpi) resulting in significantly lower values of net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E). At 8 and 24 h, the lower PN in trehalose-treated plants was accompanied by significant decrease in intercellular CO2 concentration (ci) suggesting that the reduction of PN was caused by stomatal limitation. At 48 and 72 h, trehalose decreased apparent carboxylation efficiency (PN/ci) and did not decrease ci and gs compared with controls; therefore the reduction in photosynthesis was caused by non-stomatal limitation. Trehalose treatment resulted in significantly higher effective photochemical efficiency of PS II (ΦPSII) and did not affect maximum photochemical efficiency of PS II (Fv/Fm). At 24, 48, and 72 h, trehalose decreased non-photochemical quenching (NPQ) and increased photochemical quenching (qP). Our results suggest that trehalose did not damage photosynthetic reaction centers.

Keywords

• broad bean
• chlorophyll fluorescence
• gas exchange
• net photosynthetic rate
• stomatal and non-stomatal limitations
• transpiration rate