Evaluating a novel microtensiometer for continuous trunk water potential measurements in field-grown irrigated grapevines

Autor: Vinay Pagay
Rok vydání: 2021
Předmět:
Zdroj: Irrigation Science. 40:45-54
ISSN: 1432-1319
0342-7188
Popis: Water potential (Ψw) is a fundamental thermodynamic parameter that describes the activity of water and is a key metric of plant water status. In this paper, we evaluate the continuous measurement of water potential in grapevine trunks using a novel in situ sensor known as a ‘microtensiometer’ under field conditions in two South Australian vineyards. We characterised the seasonal and diurnal dynamics of trunk water potentials (Ψtrunk) obtained from microtensiometers installed in two grapevine cultivars, Shiraz and Cabernet Sauvignon, and compared these values to pressure chamber-derived stem (Ψstem) and leaf (Ψleaf) water potentials. Diurnal patterns of Ψtrunk matched those of Ψstem and Ψleaf under low-vapour pressure deficit (VPD) conditions, but diverged under high-VPD conditions, where Ψtrunk dropped below Ψstem in the late afternoon. Interestingly, under high-VPD conditions, Ψtrunk values consistently dropped below Ψstem values around mid-afternoon with a recovery observed by early evening. The highest diurnal values of Ψtrunk were observed shortly after dawn. Ψstem was better correlated with Ψtrunk than was Ψleaf in both cultivars. Time cross-correlation analysis revealed that Shiraz Ψtrunk lagged Cabernet Ψtrunk in response to changing VPD. Microtensiometer-derived Ψtrunk generally matched the seasonal and diurnal patterns of plant Ψw obtained with a pressure chamber except under high-VPD conditions. To be useful for irrigation scheduling, where absolute values of Ψw are required, crop- and cultivar-specific thresholds of Ψtrunk need to be developed.
Databáze: OpenAIRE
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