Effects of Postharvest Water Deficits on the Physiological Behavior of Early-Maturing Nectarine Trees.

María R Conesa,M Carmen Ruiz-Sánchez,Juan Vera,Wenceslao Conejero

doi:10.3390/plants9091104

María R Conesa, M Carmen Ruiz-Sánchez + Show 2 more

Open Access

https://doi.org/10.3390/plants9091104

Copy DOI

Abstract

The physiological performance of early-maturing nectarine trees in response to water deficits was studied during the postharvest period. Two deficit irrigation treatments were applied, moderate and severe, and these were compared with a control treatment (fully irrigated). Stem water potential and leaf gas exchange (net CO2 assimilation rate, ACO2; transpiration rate, E; and stomatal conductance, gs) were measured frequently. Drought avoidance mechanisms included a decrease in stomatal conductance, especially in the case of the severe deficit treatment, which also showed a strong dependence of ACO2 on gs. Intrinsic water-use efficiency (ACO2/gs) was more sensitive than instantaneous water-use efficiency (ACO2/E) as an indicator to detect water deficit situations in nectarine trees. However, in contrast to the results obtained for other deciduous fruit trees, a poor correlation was found between ACO2/E and ACO2/gs, despite the important relation between E and gs. ACO2/E was also weakly correlated with gs, although this relationship clearly improved when the vapor pressure deficit (VPD) was included, along with gs as the independent variable. This fact reveals that apart from stomatal closure, E depends on the boundary layer conductance (gb), which is mediated by VPD through changes in wind speed. This suggests low values of the decoupling coefficient for this water-resilient species.

Highlights

Water scarcity in the semi-arid area of Spain is one of the most important environmental constrains affecting the physiology of crops
The results indicate that early-maturing nectarine trees are a resilient species that respond well to water stress, essentially by developing drought avoidance mechanisms
The water deficits applied during the postharvest period reduced plant water status and leaf gas exchange values, the most affected parameter being stomatal conductance

Summary

Introduction

Water scarcity in the semi-arid area of Spain is one of the most important environmental constrains affecting the physiology of crops. Spain is the fourth largest peach and nectarine producer with an average annual production of 1,42 Mt in the period 2015–2018 [6], acting as a leader in export to European markets. In early-maturing cultivars, fruit ripening coincides with periods of low crop evapotranspiration (ETc). Cultivation requires lower amounts of water than late-maturing cultivars, which is an important issue in semi-arid areas, where water is often a limiting factor for peach and nectarine production [4,5,6,7,8,9,10,11,12,13]

Methods

Findings

Discussion

Conclusion