Response of maize (Zea mays L.) towards vapor pressure deficit

The changing atmospheric wetness and dryness in the background of global warming is an important issue for maize cultivation. The objective of this study was to evaluate the physiological response of maize towards vapor pressure deficits (VPDs). To understand the behaviors and the morphology of the stomata that are correlated with the plant biomass and nutrient acquisition, we conducted a pot experiment of maize planting under two levels of VPDs (low 1.1 +/- 0.5 kPa; high 2.6 +/- 0.7 kPa). Plants exposed to a high VPD (HVPD) condition displayed a higher transpiration rate throughout the growth periods. Stomatal conductance and the intercellular carbon dioxide (CO2) concentration were also higher for the plants at HVPD at later growing phases. At early growth stages, stomata on the adaxial surface of the plants exposed to the HVPD environment was lower in density but they were higher in length and width at the abaxial surface than those exposed to the low VPD (LVPD) condition. HVPD increased considerably the stomatal number 50 days after sowing (d). The higher transpiration of the plants in the HVPD condition appeared to be negatively associated with the biomass and the content of the majority of nutrients. However, plants at the HVPD condition showed a significantly higher root-specific capacity for nutrient uptake and delivered a higher proportion of the absorbed nutrients towards the shoot. Therefore, stomata and nutrient uptake responses to VPD are the important traits to be considered while improving the maize for dry weather regions.