Abstract
High relative air humidity (RH ≥ 85%) during growth leads to stomata malfunctioning, resulting in water stress when plants are transferred to conditions of high evaporative demand. In this study, we hypothesized that an elevated air movement (MOV) 24 h per day, during the whole period of leaf development would increase abscisic acid concentration ([ABA]) enhancing stomatal functioning. Pot rose ‘Toril’ was grown at moderate (61%) or high (92%) RH combined with a continuous low (0.08 m s-1) or high (0.92 m s-1) MOV. High MOV reduced stomatal pore length and aperture in plants developed at high RH. Moreover, stomatal function improved when high MOV-treated plants were subjected to leaflet desiccation and ABA feeding. Endogenous concentration of ABA and its metabolites in the leaves was reduced by 35% in high RH, but contrary to our hypothesis this concentration was not significantly affected by high MOV. Interestingly, in detached leaflets grown at high RH, high MOV increased stomatal sensitivity to ABA since the amount of exogenous ABA required to decrease the transpiration rate was significantly reduced. This is the first study to show that high MOV increases stomatal functionality in leaves developed at high RH by reducing the stomatal pore length and aperture and enhancing stomatal sensitivity to ABA rather than increasing leaf [ABA].
Highlights
Stomatal opening and closing are influenced by environmental factors such as light, temperature, CO2 concentration, drought, relative air humidity (RH) and their interactions
At growth conditions during the light period, high MOV increased the transpiration rate by 12% in intact plants grown at moderate RH, while it was decreased by 17% in high RH-grown plants (P < 0.001; Figure 1A)
The current work shows for the first time that high MOV during leaf development improves stomatal functioning of leaves developed at high RH
Summary
Stomatal opening and closing are influenced by environmental factors such as light, temperature, CO2 concentration, drought, RH and their interactions (Tallman, 2004; Reynolds-Henne et al.Stomatal responses to air movement2010; Feller and Vaseva, 2014). Stomatal opening and closing are influenced by environmental factors such as light, temperature, CO2 concentration, drought, RH and their interactions Long-term high RH (i.e., RH ≥ 85% throughout leaf ontogeny) is regarded as the environmental factor that mostly disturbs the capacity of stomata to close in response to water stress and darkness, leading to uncontrolled water loss (Torre et al, 2003; Rezaei Nejad and van Meeteren, 2005; In et al, 2006; Fanourakis et al, 2012). The reasons why stomata fail to close fully during water stress periods in plants grown under long-term high RH remain unclear
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call