|Author:||Rodrigues, M. Luc©Ưlia ; Maroco, Jo©Đo P. ; Pereira, Jo©ĐoS. ; Chaves, M. Manuela ; Lopes, Carlos M. ; Santos, Tiago P. ; Rodrigues, Ana P. ; de Souza, Claudia R.|
|Book Group Author:||NA|
Effects of irrigation strategies on stomata and plant water use were studied in field-grown grapevines (Vitis vinifera L.). We assessed the importance of root-derived chemical signals vs. hydraulic signalling in stomatal regulation. The experiment included two treatments with the same water added to the soil (50% ETc) applied either to the whole root system (DI) or to half of the roots, alternating irrigation side every 15 days (PRD). Well-watered plants (FI) (100% ETc) and non-irrigated grapevines (NI) were also studied. Partial stomata closure occurred in both PRD and DI plants. [ABA] of xylem sap remained constant during the day and was maintained throughout the season, with higher values in NI plants. Xylem sap pH was not affected by soil water availability. A positive correlation between ψpd and maximum gs was found, indicating that grapevine stomata strongly respond to plant water status. In contrast, ABA did not explain stomatal control at veraison. At mid-ripening gs was significantly correlated with ABA, apparently interacting with the rise in xylem sap pH. Therefore, our data suggest that hydraulic feedback and feed-forward root-to-shoot chemical signalling mechanisms might be involved in the control of stomata in response to decreased soil water availability, hydraulic signals playing the dominant role.
|Pages:||565 - 579|
|Journal:||Functional plant biology FPB|
xylem, diurnal variation, abscisic acid, sap, pH,developmental stages, plant development, plant available water, soilwater content, root systems, stomatal conductance, plant-waterrelations, Vitis vinifera, grapes, water use, stomatal movement,stomata, deficit irrigation, signal transduction, Portugal