Articles
Evaluation of tree transpiration of the pummelo (Citrus grandis L.) ‘Thong-Dee’ under varied environmental conditions
Article number
1253_42
Pages
319 – 326
Language
English
Abstract
Generally, tree transpiration is regulated by soil moisture and evaporative demand.
This work evaluated the tree transpiration of the commercial pummelo ‘Thong-Dee’ by the xylem sap flow method.
Our experiments were conducted on a farmer’s plantation, located in the Kasetsomboon district, Chaiyaphum province of northeast Thailand.
The samples included three trees, six years of age, with an average trunk girth of 74.8cm; in which a sap flow probe was inserted into the trunk at 30cm above soil in the north azimuth.
The data was recorded through the transient thermal dissipation method (10 min of heating and 20 min of cooling in a half-hour period; TTD10) with a Granier type probe.
Data were calculated for both sap flux density (Js) and daily tree transpiration (ET). The results indicated a fluctuation of tree water movement according to the soil moisture and air evaporative demand.
Soil drought was found to decrease the xylem water transport, while air evaporative demand increased tree transpiration.
However, tree transpiration was inhibited in the extreme evaporative demand condition.
The diurnal sap flux density data also confirmed that the limitation of sap flux density occurs in both soil drought and low evaporative demand conditions.
Our results also showed that the potential tree transpiration of the six-year-old pummelo ‘Thong-Dee’ was greater than 100 L day‑1.
This work evaluated the tree transpiration of the commercial pummelo ‘Thong-Dee’ by the xylem sap flow method.
Our experiments were conducted on a farmer’s plantation, located in the Kasetsomboon district, Chaiyaphum province of northeast Thailand.
The samples included three trees, six years of age, with an average trunk girth of 74.8cm; in which a sap flow probe was inserted into the trunk at 30cm above soil in the north azimuth.
The data was recorded through the transient thermal dissipation method (10 min of heating and 20 min of cooling in a half-hour period; TTD10) with a Granier type probe.
Data were calculated for both sap flux density (Js) and daily tree transpiration (ET). The results indicated a fluctuation of tree water movement according to the soil moisture and air evaporative demand.
Soil drought was found to decrease the xylem water transport, while air evaporative demand increased tree transpiration.
However, tree transpiration was inhibited in the extreme evaporative demand condition.
The diurnal sap flux density data also confirmed that the limitation of sap flux density occurs in both soil drought and low evaporative demand conditions.
Our results also showed that the potential tree transpiration of the six-year-old pummelo ‘Thong-Dee’ was greater than 100 L day‑1.
Authors
S. Isarangkool Na Ayutthaya, S. Meetha, R. Nampila, S. Techawongstien
Keywords
Citrus grandis L., water use, sap flow, soil drought, evaporative demand
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