TY - JOUR

T1 - Irrigation frequency transiently alters whole plant gas exchange, water and hormone status, but irrigation volume determines cumulative growth in two herbaceous crops

AU - Puertolas Simon, Jaime

AU - Albacete, Alfonso

AU - Dodd, Ian

N1 - This is the author’s version of a work that was accepted for publication in Environmental and Experimental Botany. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Environmental and Experimental Botany, 176, 2020 DOI: 10.1016/j.envexpbot.2020.104101

PY - 2020/8/1

Y1 - 2020/8/1

N2 - Physiological effects of irrigation frequency, at the same irrigation volume, have received little attention but might determine crop yield and water use efficiency. Potted plants of two species, tomato and basil, received two irrigation treatments that both supplied the same irrigation volume (75% of that received by a well-watered treatment - WW), but either frequently (once or twice per day-FDI) or infrequently (every three days-IDI). Stem diameter variations, whole-plant gas exchange, root and leaf water potential, and foliar hormones were monitored for 11 days after applying the treatments, and whole-plant biomass accumulation determined at the end of that period. Treatments showed temporal and spatial differences in soil moisture, with FDI resulting in a wet upper layer and dry lower layer. In both species, water stress integral in IDI was three-fold higher than in FDI, and gas exchange lower than FDI plants. Despite these differences, both treatments accumulated biomass and stem diameter growth similarly. In tomato, IDI induced compensatory stem growth (higher than WW plants) after re-watering, and attenuated hormone accumulation (lower jasmonic, gibberellic, and salicylic acid concentrations than FDI plants) that maintained growth. In basil, stem growth of IDI plants only recovered to WW and FDI levels upon re-watering, but lower sensitivity of stem growth to water deficits explained similar final biomass accumulation to FDI plants. Although both deficit irrigation treatments showed similar cumulative growth, temporal differences in physiological responses suggest that irrigation frequency could be tailored to specific crop species depending on their sensitivity to soil water deficits and re-hydration.

AB - Physiological effects of irrigation frequency, at the same irrigation volume, have received little attention but might determine crop yield and water use efficiency. Potted plants of two species, tomato and basil, received two irrigation treatments that both supplied the same irrigation volume (75% of that received by a well-watered treatment - WW), but either frequently (once or twice per day-FDI) or infrequently (every three days-IDI). Stem diameter variations, whole-plant gas exchange, root and leaf water potential, and foliar hormones were monitored for 11 days after applying the treatments, and whole-plant biomass accumulation determined at the end of that period. Treatments showed temporal and spatial differences in soil moisture, with FDI resulting in a wet upper layer and dry lower layer. In both species, water stress integral in IDI was three-fold higher than in FDI, and gas exchange lower than FDI plants. Despite these differences, both treatments accumulated biomass and stem diameter growth similarly. In tomato, IDI induced compensatory stem growth (higher than WW plants) after re-watering, and attenuated hormone accumulation (lower jasmonic, gibberellic, and salicylic acid concentrations than FDI plants) that maintained growth. In basil, stem growth of IDI plants only recovered to WW and FDI levels upon re-watering, but lower sensitivity of stem growth to water deficits explained similar final biomass accumulation to FDI plants. Although both deficit irrigation treatments showed similar cumulative growth, temporal differences in physiological responses suggest that irrigation frequency could be tailored to specific crop species depending on their sensitivity to soil water deficits and re-hydration.

KW - Whole-plant photosynthesis

KW - stem diameter variations

KW - abscisic acid

KW - jasmonic acid

KW - gibberillic acid

KW - Salicylic acid

U2 - 10.1016/j.envexpbot.2020.104101

DO - 10.1016/j.envexpbot.2020.104101

M3 - Journal article

VL - 176

JO - Environmental and Experimental Botany

JF - Environmental and Experimental Botany

SN - 0098-8472

M1 - 104101

ER -