Stomatal and environmental control of transpiration in a lowland tropical forest tree Export

@article{citeulike:4301738, abstract = {Stomatal control of crown transpiration was studied in Anacardium excelsum, a large-leaved, emergent canopy species common in the moist forests of Central and northern South America. A construction crane equipped with a gondola was used to gain access to the uppermost level in the crown of a 35-m-tall individual. Stomatal conductance at the single leaf scale, and transpiration and total vapour phase conductance (stomatal and boundary layer) at the branch scale were measured simultaneously using the independent techniques of porometry and stem heat balance, respectively. This permitted the sensitivity of transpiration to a marginal change in stomatal conductance to be evaluated using a dimensionless coupling coefficient (1-03C9) ranging from zero to 1, with 1 representing maximal stomatal control of transpiration. Average stomatal conductance varied from 0.09 mol m22122 s22121 during the dry season to 0.3 mol m22122 s22121 during the wet season. Since boundary layer conductance was relatively low (0.4 mol m22122 s22121), 1-03C9 ranged from 0.46 during the dry season to only 0.25 during the wet season. A pronounced stomatal response to humidity was observed, which strongly limited transpiration as evaporative demand increased. The stomatal response to humidity was apparent only when the leaf surface was used as the reference point for measurement of external vapour pressure. Average transpiration was predicted to be nearly the same during the dry and wet seasons despite a 1 kPa difference in the prevailing leaf-to-air vapour pressure difference. The patterns of stomatal behaviour and transpiration observed were consistent with recent proposals that stomatal responses to humidity are based on sensing the transpiration rate itself.}, address = {Hawaiian Sugar Planters' Association, PO Box 1057, Aiea, HI 96701, USA; Department of Botany, University of Hawaii, Honolulu, HI 96822, USA; Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA; Laboratory of Biomedical and Environmental Sciences, University of California, Los Angeles, CA 90024, USA; Departmento de Ciencias Biolgicas, Universidadde los Andes, Bogot, Colombia}, author = {Meinzer, F. C. and Goldstein, G. and Holbrook, N. M. and Jackson, P. and Cavelier, J.}, citeulike-article-id = {4301738}, citeulike-linkout-0 = {http://dx.doi.org/10.1111/j.1365-3040.1993.tb00889.x}, citeulike-linkout-1 = {http://www3.interscience.wiley.com/cgi-bin/abstract/119300403/ABSTRACT}, doi = {10.1111/j.1365-3040.1993.tb00889.x}, journal = {Plant, Cell and Environment}, number = {4}, pages = {429--436}, posted-at = {2009-04-11 19:06:13}, priority = {2}, title = {Stomatal and environmental control of transpiration in a lowland tropical forest tree}, url = {http://dx.doi.org/10.1111/j.1365-3040.1993.tb00889.x}, volume = {16}, year = {1993} }

TY - JOUR ID - citeulike:4301738 L3 - citeulike-article-id:4301738 N2 - Stomatal control of crown transpiration was studied in Anacardium excelsum, a large-leaved, emergent canopy species common in the moist forests of Central and northern South America. A construction crane equipped with a gondola was used to gain access to the uppermost level in the crown of a 35-m-tall individual. Stomatal conductance at the single leaf scale, and transpiration and total vapour phase conductance (stomatal and boundary layer) at the branch scale were measured simultaneously using the independent techniques of porometry and stem heat balance, respectively. This permitted the sensitivity of transpiration to a marginal change in stomatal conductance to be evaluated using a dimensionless coupling coefficient (1-03C9) ranging from zero to 1, with 1 representing maximal stomatal control of transpiration. Average stomatal conductance varied from 0.09 mol m22122 s22121 during the dry season to 0.3 mol m22122 s22121 during the wet season. Since boundary layer conductance was relatively low (0.4 mol m22122 s22121), 1-03C9 ranged from 0.46 during the dry season to only 0.25 during the wet season. A pronounced stomatal response to humidity was observed, which strongly limited transpiration as evaporative demand increased. The stomatal response to humidity was apparent only when the leaf surface was used as the reference point for measurement of external vapour pressure. Average transpiration was predicted to be nearly the same during the dry and wet seasons despite a 1 kPa difference in the prevailing leaf-to-air vapour pressure difference. The patterns of stomatal behaviour and transpiration observed were consistent with recent proposals that stomatal responses to humidity are based on sensing the transpiration rate itself. IS - 4 JF - Plant, Cell and Environment AD - Hawaiian Sugar Planters' Association, PO Box 1057, Aiea, HI 96701, USA; Department of Botany, University of Hawaii, Honolulu, HI 96822, USA; Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA; Laboratory of Biomedical and Environmental Sciences, University of California, Los Angeles, CA 90024, USA; Departmento de Ciencias Biolgicas, Universidadde los Andes, Bogot, Colombia EP - 436 TI - Stomatal and environmental control of transpiration in a lowland tropical forest tree VL - 16 SP - 429 AU - Meinzer, FC AU - Goldstein, G AU - Holbrook, NM AU - Jackson, P AU - Cavelier, J PY - 1993/// UR - http://dx.doi.org/10.1111/j.1365-3040.1993.tb00889.x ER -