Disentangling the Effects of Water Stress on Carbon Acquisition, Vegetative Growth, and Fruit Quality of Peach Trees by Means of the QualiTree Model

Abstract

Climate change projections predict warmer and drier conditions. In general, moderate to severe water stress reduce plant vegetative growth and leaf photosynthesis. However, vegetative and reproductive growths show different sensitivities to water deficit. In fruit trees, water restrictions may have serious implications not only on tree growth and yield, but also on fruit quality, which might be improved. Therefore, it is of paramount importance to understand the complex interrelations among the physiological processes involved in within-tree carbon acquisition and allocation, water uptake and transpiration, organ growth, and fruit composition when affected by water stress. This can be studied using process-based models of plant functioning, which allow assessing the sensitivity of various physiological processes to water deficit and their relative impact on vegetative growth and fruit quality. In the current study, an existing fruit-tree model (QualiTree) was adapted for describing the water stress effects on peach (Prunus persica L. Batsch) vegetative growth, fruit size and composition. First, an energy balance calculation at the fruit-bearing shoot level and a water transfer formalization within the plant were integrated into the model. Next, a reduction function of vegetative growth according to tree water status was added to QualiTree. Then, the model was parameterized and calibrated for a late-maturing peach cultivar (“Elberta”) under semi-arid conditions, and for three different irrigation practices. Simulated vegetative and fruit growth variability over time was consistent with observed data. Sugar concentrations in fruit flesh were well simulated. Finally, QualiTree allowed for determining the relative importance of photosynthesis and vegetative growth reduction on carbon acquisition, plant growth and fruit quality under water constrains. According to simulations, water deficit impacted vegetative growth first through a direct effect on its sink strength, and; secondly, through an indirect reducing effect on photosynthesis. Fruit composition was moderately affected by water stress. The enhancements performed in the model broadened its predictive capabilities and proved that QualiTree allows for a better understanding of the water stress effects on fruit-tree functioning and might be useful for designing innovative horticultural practices in a changing climate scenario.

Regulation of phytochemicals in fruits and berries by environmental variation—Sugars and organic acids

“…Bordonaba and Terry () reported that the content of total sugars decreased from 70.8 to 67.1 mg/g FW in strawberry cutivar Florence, but increased from 58.6 and 68.8 to 82.3 and 81.6 mg/g FW, respectively, in cultivars Elsanta and Sonata, and did not change significantly in cultivars Christine and Symphony under low level of irrigation. In the case of fructose and glucose, irrigation exhibited negative impacts on the contents of these two sugars in fruits of satsuma mandarins (Yakushiji, Morinaga, & Nonami, ) and peach (Rahmati et al, ), but had no impact on their contents in kiwifruits (Miller, Smith, Boldingh, & Johansson, ). The impact of deficient irrigation on sucrose content in fruits of nectarine, peach, plum, satsuma mandarins, mango fruit, and strawberry were also investigated.…”

“…Elevations in sucrose content in fruits of nectarine (Thakur & Singh, ), plum (Maatallah et al, ), and satsuma mandarins (Yakushiji et al, ) were detected under deficient irrigation, while no impact of such condition on the sucrose content in mango fruit and strawberry (Bordonaba & Terry, ; Terry et al, ) were found. In peach, the content of sucrose decreased in response to increased water deficit (Rahmati et al, ). The plants growing wildly will never be irrigated, but precipitation contributes in the same way as irrigation to the plant growth.…”

Effects of Soil Water Deficit on Three Tree Species of the Arid Environment: Variations in Growth, Physiology, and Antioxidant Enzyme Activities

“…During the early stage of water stress, plants maintain the leaf water potential and CO 2 assimilation rate by decreasing stomatal conductance [11]. However, under severe and prolonged water stress, excessive decrease in stomatal conductance may result in decrease in CO 2 assimilation rate [7,12]. In addition, plants strive to maintain the water balance under drought stress by excessive production of proline and soluble sugars that helps maintaining the osmotic pressure in the cytoplasm [11].…”

Effects of Exogenous Dopamine on the Uptake, Transport, and Resorption of Apple Ionome Under Moderate Drought

“…Over the past few decades, the frequency and intensity of regional and global extremes in water deficits have increased. Its impact on growth, morphology, and physiological processes within the aboveground and belowground parts of a plant can be measured in several ways, e.g., gas exchange, stomatal conductance, water relations, root longevity, leaf water potential, activity of phytohormones and reactive oxygen species, cell division, nutrient assimilation and transport, and metabolic processes ( Ergo et al, 2018 ; Rahmati et al, 2018 ). Under drought conditions, plants generally close their stomata to minimize water losses, thereby reducing photosynthetic capacity.…”