Fruit and Leaf Sensing for Continuous Detection of Nectarine Water Status.

Alessio Scalisi,Dario Stefanelli,Mark Glenn O’Connell,Riccardo Lo Bianco

doi:10.3389/fpls.2019.00805

Alessio Scalisi, Dario Stefanelli + Show 2 more

Open Access

https://doi.org/10.3389/fpls.2019.00805

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Abstract

Continuous assessment of plant water status indicators provides the most precise information for irrigation management and automation, as plants represent an interface between soil and atmosphere. This study investigated the relationship of plant water status to continuous fruit diameter (FD) and inverse leaf turgor pressure rates (pp) in nectarine trees [Prunus persica (L.) Batsch] throughout fruit development. The influence of deficit irrigation treatments on stem (Ψstem) and leaf water potential, leaf relative water content, leaf stomatal conductance, and fruit growth was studied across the stages of double-sigmoidal fruit development in ‘September Bright’ nectarines. Fruit relative growth rate (RGR) and leaf relative pressure change rate (RPCR) were derived from FD and pp to represent rates of water in- and outflows in the organs, respectively. Continuous RGR and RPCR dynamics were independently and jointly related to plant water status and environmental variables. The independent use of RGR and RPCR yielded significant associations with midday Ψstem, the most representative index of tree water status in anisohydric species. However, a combination of nocturnal fruit and leaf parameters unveiled an even more significant relationship with Ψstem, suggesting a changing behavior of fruit and leaf water flows in response to pronounced water deficit. In conclusion, we highlight the suitability of a dual-organ sensing approach for improved prediction of tree water status.

Highlights

Precision irrigation is becoming a crucial management approach for environmentally and economically sustainable fruit tree production
This study aimed to investigate the relationship of Ψstem and other plant water status indicators to continuous fruit size and leaf turgor pressure dynamics in nectarine trees [Prunus persica (L.) Batsch] subjected to DI at each of the individual stages of fruit growth
Maximum ET0 occurred at stage IIIa (Figure 1A, Table 1), driven by a combination of high T and low Relative humidity (RH) which caused a rise in vapor pressure deficit (VPD) (Figure 1D)

Summary

Introduction

Precision irrigation is becoming a crucial management approach for environmentally and economically sustainable fruit tree production. In most cases of fruit crops cultivated in dry areas, rainfed agriculture is not sustainable and deficit irrigation (DI) is a reasonable strategy to improve water use efficiency. Fereres and Soriano (2007) highlighted the benefits of regulated DI as a strategy to reduce agricultural water use. The main purpose of regulated DI is to reduce irrigation at specific developmental stages of the crop with no or limited effects on yield. The use of DI in different phenological stages of fruit crops started in the 1980s by Chalmers et al (1981, 1986). Water supply for DI treatments is often calculated as a fraction of crop evapotranspiration (ETc)

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