Calibration of Thermal Dissipation Probes for Date Palm (Phoenix dactylifera L.)

Abstract

The quantification of water flow through the stem is vital for date palm (Phoenix dactylifera L.) to promote a good water stress management. The thermal dissipation probe (TDP) method developed by Granier is widely used to evaluate transpiration of forest trees; however, there are contradictory reports regarding its reliability. Considerable errors in estimated sap flux density, which might be due to a lack ofspecies-specific calibrations. The TDP method uses a mathematical model that is based on an empirical equation to estimate sap flux density, which is claimed to be applicable to all tree species, independently of wood structure and anatomy. At the laboratory, we compared the rate of water uptake by cut stems with sap flux estimates derived from the TDP method to assess the validity of the method.Our calibration results were considerably different compared to the Granier’s original equation. Moreover, sap flux density was overestimated by 18.2±0.5% when the original calibration parameters of Granierare employed. However,using new calibration parameters improved the accuracy of sap flow measurements. Our results indicated that it is not appropriate to use a general equation for different species. Therefore, previous estimations of date palm’s water requirement through thermal dissipation probes should be revised.

Applicability of Thermal Dissipation Method in Sap Flow Measurement of Karst Shrub Community

“…This may be due to the small specificity of coefficient β. There also showed an extensive range of variation in coefficient α and a slight variation in coefficient β [7,21,22,24]. Furthermore, it has been observed that the CV exhibits a significantly negative correlation with coefficient α, whereas its correlation with β remains insignificant.…”

“…To test the relationship between wood structures and the calibration parameters of the Granier formula on a broader scale, both measured data in this study and published data were used. The published calibration and wood structure data were directly retrieved from tables or the TRY database [2,6,8,10,11,15,16,[18][19][20][21][22][23][24]26,27,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. To enlarge the data range, the published calibrated species that found only one or two structure parameters were also included in this analysis.…”

“…There are three main correction methods of Grainer's original formula: the whole-tree container method [2,[12][13][14][15], the broken-root container method [5,16,17], and the isolated stem segment method [18][19][20][21]. Among them, the whole-tree container method retains all the complete organs of the tree, closest to the natural growth state, and is the ideal calibration method for the sap flow density formula [22].…”

Effect of period of receptivity and air temperature on parthenocarpic phenomenon of ‘Assiane’ date palm cultivar (Phoenix dactylifera L.)

“…Environmental conditions can have a significant impact on the pollination and fertilization processes. Optimal temperature is essential for different stages of sexual reproduction in flowering plants, such as pollen formation, pollen transfer, the readiness of stigmas for pollen, pollen germination, the growth of pollen tubes, double fertilization, and seed development (Hedhly et al, 2003(Hedhly et al, , 2005Snider and Oosterhuis, 2011;Zulkarnain et al, 2019;Ali-Dinar et al, 2021;Alla et al, 2022). Any form of stress during these stages can result in sterility and, ultimately, reduce crop yields.…”