Influence of irrigation and fertilization on transpiration and hydraulic properties of Populus deltoides.
Summary Long-term hydraulic acclimation to resource availability was explored in 3-year-bld Populus deltoides Bartr. ex Marsh. clones by examining transpiration. leaf-specific hydraulic conductance (GL), canopy stomatal conductance (Gs) and leaf to sapwood area ratio (AL:Asi)n response to imgation (13 and 551 mm year in addition to ambient precipitation) and fertilization (0 and 120 kg N ha-' year-'). Sap flow was measured continuously over one growing season with thermal dissipation probes. Fertilization had a greater effect on growth and hydraulic properties than imgation, and fertilization effects were independent of irrigation treatment. Transpiration on a ground area basis (E) ranged between 0.3 and 1.8 mm day-', and increased 66% and 90% in response to imgation and fertilization, respectively. Increases in GL, Gs at a reference vapor pressure deficit of 1 kPa, and transpiration per unit leaf areain response to increases in resource availability were associated with reductions in AL:As and consequently a minimal change in the water potential gradient from soil to leaf. Imgation and fertilization increased leaf area index similarly, from an average 1.16 in control stands to 1.45, but sapwood area was increased from 4.0 to 6.3 m ha-' by irrigation and from 3.7 to 6.7 m2 ha-' by fertilization. The balance between leaf area and sapwood area was important in understanding long-term hydraulic acclimation to resource availability and mechanisms controlling maximum productivity in Populus deltoides.
- Research Organization:
- USDA Forest Service, Savannah River, New Ellenton, SC (United States)
- Sponsoring Organization:
- USDOE - Office of Environmental Management (EM)
- DOE Contract Number:
- AI09-00SR22188
- OSTI ID:
- 936180
- Report Number(s):
- na; TRPHEM; 07-14-P; TRN: US201103%%70
- Journal Information:
- Tree Physiology, Vol. 27, Issue 1; ISSN 0829-318X
- Country of Publication:
- United States
- Language:
- English
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