Location: Adaptive Cropping Systems LaboratoryTitle: Physiological responses of drought stressed maize to contrast evaporative demand conditions
|MURA, JYOSTA - Orise Fellow|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/5/2019
Publication Date: N/A
Technical Abstract: Drought is a significant factor limiting maize growth and productivity. Water stress in plants depends both on the supply of water to the soil and the evaporative demand of the atmosphere. Maize growth and development response to different soil water content under two contrasting evaporative demand conditions were tested in two experiments conducted in growth chambers. In this study, the physiological response of maize was analyzed under low (1 kPa Vapor Pressure Deficit VPD) and high (4 kPa VPD) evaporative demand conditions at three different soil water content (SWC); well-watered, 45% SWC (medium) and 35% (low). Under well-watered conditions, low VPD resulted in high relative growth rate (RGR) than high VPD. Water deficit stress inhibited the plant growth but the effects were more significant under high VPD conditions than low VPD. The plants grown at low SWC under high VPD had low RGR compared to all other treatments. The negative effects of high VPD reduced average photosynthetic rates and leaf area expansion in drought-stressed plants which might have caused the reduction in RGR due to decreased carbon metabolism. The whole plant hydraulic conductance was higher under low VPD than high VPD in drought-stressed plants suggesting water stress effect was moderated by low evaporative demand environment. The expression of ABA transcription factor showed significant variation (P<0.01) among treatments and also co-related to the amount of Abscisic Acid ABS only under drought stress conditions. In summary, low SWC limits maize growth with higher magnitude if coupled with high VPD. These results also suggest that the growth responses of maize to soil water deficit and evaporative demand includes different mechanisms involving chemical signals and hydraulic processes.