Effect of Irrigation Regime on Photosynthesis and Leaf Water Potential of Vitis Vinifera L. (Cv. Alphonze Lavallé) in Venezuela

Effects of moderate irrigation on vegetative growth and productive parameters of Monastrell vines grown in semiarid conditions

“…Water stress decreased photosynthetic activity as also found by other authors (Poni et al, 1994b;Araujo et al, 1999;Flexas et al, 1999) although it has been stated that, even in hard environmental conditions, vine leaves are capable of maintaining a certain degree of photosynthetic activity (Kliewer et al, 1983;Escalona et al, 1997). Taking into account that photosynthesis decreases when Ψ reaches -0.5 Mpa and ceases around -1.2 MPa (Hardie and Considine, 1976), the values we observed in predawn water potential in non-irrigated vines show that photosynthesis may be impaired in the hottest months.…”

Addressing Water Stress and Climate Variability in the Mediterranean: Study of Regulated Deficit Irrigation (RDI) and Non-Irrigation (NI) in Tempranillo and Cabernet Sauvignon (Vitis vinifera L.)

“…Ref. [69] with Cabernet Sauvignon and [28,36] with Tempranillo agree in finding that during the period prior to the outbreak, the potential recovery begins at 4 p.m. (solar time), equaling the dawn value only in the case of the irrigation treatment. After the outbreak, in none of the treatments, the recovery potential is equal to the values presented at dawn.…”

“…As the season progresses, all the authors agree that the potential at dawn shows a clear decreasing trend in the non-irrigated vines, while the irrigated plants maintain more moderate potentials, with gentle falls throughout the summer until the month of August, when an important recovery of potential begins to occur. This tells us that the plant achieves a better nighttime rehydration capacity because of irrigation, while reflecting the greater availability of water in the soil in those treatments that involve an additional contribution of water [28,36].…”

“…Diurnal fluctuations in the leaf water potential occur during situations of abundant water availability and physiological proximity to maturation. The potential, with values around (−0.2) MPa at dawn, declines throughout the day in response to increasing evaporative demand, reaching values near (−1.2) and (−1.3) MPa [28][29][30][31][32]. The approximation of the water potential to its maximum value (less negative) varies based on whether the vines are irrigated or non-irrigated, as well as the stage of the growth cycle.…”