Usefulness of the ZIM-probe technology for detecting water stress in clementine and persimmon trees

Abstract

Further improvement on irrigation management requires continuous plant water status monitoring. The non-invasive ZIM-probe measures the pressure (Pp) transfer function through a patch of an intact leaf, which is inversely correlated with the turgor pressure. Data are sent wireless in real-time by telemetry to an Internet server via a mobile phone network where it is available to be analyzed. In this work, the detection of water stress by measuring relative changes in turgor pressure with the ZIM-probe was evaluated in clementine and persimmon trees. Ten trees of both species were equipped with two ZIM-probes each located at the east side of the canopy. The ZIM-probes were used over several months during which half of the trees were subjected to two drought cycles. Concomitant measurements of stem water potential (ψs) were taken at midday in both orchards during the drought periods. Additionally, determinations of ψs and stomatal conductance (gs) were also performed during 1-2 days at hourly intervals in the clementine and persimmon orchards, respectively, to study the existing relationship of these classical indicators with the leaf turgor pressure. Results showed that diurnal Pp values increased in nonirrigated clementine trees when water restrictions were imposed. Persimmon drought-stressed trees, on the other hand, showed different Pp curve shapes (half and complete inverse curve) depending on the level of stress reached by the trees. There was a tight correlation between the hourly spot measurements of ψs and gs with the probe data. Overall, results show that the ZIM-probe enables the detection of drought stress in clementine and persimmon trees. Nevertheless, different approaches for calculating the water stress level must be used in each of these species due to the higher tendency of persimmon leaves to the inversed Pp curve phenomena.

Evaluating the usefulness of continuous leaf turgor pressure measurements for the assessment of Persimmon tree water status

“…Different approaches can be followed to detect plant water stress when analyzing data from the Yara ZIM-probes (Zimmermann et al 2013b). The assessment of the maximum daily P p seems to be a useful method for clementine trees, in which a half or complete inversion of the P p curve does not often occur even under severe (Ψ stem of up to −1.9 MPa) water-stressed conditions (Ballester et al 2016). Contrary to this and more in the line of what has been reported for other crops like almond, eucalyptus, avocado (Zimmermann et al 2013b) and olive trees (Fernández et al 2011;Ehrenberger et al 2012;Padilla-Díaz et al 2015), the change observed in the P p curve profile was shown as a useful method to detect drought stress in Persimmon trees.…”

Fruit and Leaf Sensing for Continuous Detection of Nectarine Water Status

“…Olive is cultivated in dry or semi-dry regions with limited or no irrigation water supply. LPCP probes were also related to plant water status indicators in other fruit crops, such as banana (Zimmermann et al, 2010), grapevine (Rüger et al, 2010), clementine (Ballester et al, 2017), and persimmon (Ballester et al, 2017; Martínez-Gimeno et al, 2017). However, as for fruit sensors, the use of LPCP probes alone can only give partial information on whole plant water status, unless many sensors are used on a tree.…”

The Green Side of the Water Cycle: New Advances in the Study of Plant Water Dynamics

“…Olive is cultivated in dry or semi-dry regions with limited or no irrigation water supply. LPCP probes were also related to plant water status indicators in other fruit crops, such as banana (Zimmermann et al, 2010), grapevine (Rüger et al, 2010), clementine (Ballester et al, 2017), and persimmon (Ballester et al, 2017;Martínez-Gimeno et al, 2017). However, as for fruit sensors, the use of LPCP probes alone can only give partial information on whole plant water status, unless many sensors are used on a tree.…”