|Author:||Souza, C. R. de ; Maroco, J. P. ; Santos, T. P. dos ; Rodrigues, M. L. ; Lopes, C. M. ; Pereira, J. S. ; Chaves, M. M.|
|Book Group Author:||NA|
The effects of 'partial root zone drying' (PRD) irrigation compared with other irrigation systems, namely non-irrigated (NI), full irrigation (FI) and deficit irrigation (DI), on stomatal conductance and carbon assimilation were evaluated in grapevines (Vitis vinifera cv. Moscatel) grown in the field (Portugal). At the end of the growing season, pre-dawn leaf water potential was highest in FI (-0.18±0.01 MPa; mean±s.e.), intermediate in PRD (-0.30±0.01 MPa) and DI (-0.36±0.02 MPa), and lowest in NI vines (-0.64±0.03 MPa). Stomatal conductance measured under controlled conditions of light and temperature was reduced in NI (~60%) and PRD (~30%) vines compared with DI and FI vines. Under ambient conditions, NI vines had lower rates of stomatal conductance (~26%), net CO2 assimilation (~28%) and light-adapted PSII quantum yields (~47%) than PRD, DI and FI vines. No significant differences were found among the three irrigated treatments. Both maximum electron transport (Jmax; ~30%) and triose-phosphate utilization rates (~20%) were significantly lower in NI and PRD vines than in DI and FI vines. Carbon isotope composition (δ13C) of grape berries was highest in NI vines (-24.3 per mil), followed by PRD (-25.4 per mil) and DI (-25.8 per mil) and lowest in FI (-26.4 per mil) vines, suggesting a long-term increase in the efficiency of leaf gas exchange in NI compared with PRD, DI and FI vines. Sap flow data and estimates of relative stomatal limitation are in accordance with the observed stomatal closure in PRD vines. In this study, we show that PRD irrigation was able to maintain a vine water status closed to FI, but with double water use efficiency, which was due to a reduction of stomatal conductance with no significant decrease in carbon assimilation.
|Pages:||653 - 662|
|Journal:||Functional Plant Biology|
electron transfer, fruits, grapes, irrigation, irrigationsystems, leaf conductance, leaf water potential, light, photosynthesis,photosystem II, roots, sap flow, stomata, stress, stress response,temperature, water stress, water use efficiency, Portugal, Vitis, Vitisvinifera, Vitidaceae, Rhamnales, dicotyledons, angiosperms,Spermatophyta, plants, eukaryotes, Vitis, Southern Europe, Europe,Mediterranean Region, Developed Countries, European Union Countries,OECD Countries, carbon assimilation, carbon dioxide fixation, electronflow, electron transport, sap ascent, Vitaceae, watering, HorticulturalCrops (FF003) (New March 2000), Plant Physiology and Biochemistry(FF060), Plant Water Relations (FF062), Soil Water Management(Irrigation and Drainage) (JJ800) (Revised June 2002) [formerly SoilWater Management]