HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (18) Citing Articles via Google Scholar Google Scholar Articles by Richardson, A. D. Articles by Berlyn, G. P. Search for Related Content PubMed Articles by Richardson, A. D. Articles by Berlyn, G. P. Agricola Articles by Richardson, A. D. Articles by Berlyn, G. P.

Spectral reflectance and photosynthetic properties of Betula papyrifera (Betulaceae) leaves along an elevational gradient on Mt. Mansfield, Vermont, USA¹

Yale University, School of Forestry and Environmental Studies, 370 Prospect Street, New Haven, Connecticut 06511 USA

We studied relationships between spectral reflectance and photosynthesis of mountain paper birch, Betula papyrifera var. cordifolia (Regel) Fern., leaves from three different elevations on Mt. Mansfield (summit elevation 1339 m above sea level) in the Green Mountains of Vermont, USA. The different reflectance indices we used all suggested progressively increasing stress with increasing elevation. The photochemical reflectance index (PRI) indicated lower photosynthetic radiation use efficiency at higher elevations, the red edge position (RE) indicated lower chlorophyll concentrations at higher elevations, and the structure-independent pigment index (SIPI) indicated a higher carotenoid : chlorophyll a ratio at higher elevations. The rate of change in these indices with changes in elevation was much higher than we have observed in our studies of red spruce and balsam fir reflectance along a similar elevational gradient; we take this to be an indicator of the greater susceptibility of paper birch to elevation-related stressors compared to the very stress-tolerant conifers. At all light levels, photosynthesis decreased with increasing elevation; this pattern was most noticeable in the light-saturated rate of photosynthesis (A_sat), which was nearly twice as high in low-elevation leaves (17.0 ± 1.0 µmol·m^–2·s^–1) than in high-elevation leaves. The quantum yield of photosynthesis () exhibited a similar trend. Furthermore, the highest elevation leaves showed a much sharper transition from the light-limited to the light-saturated part of the light response curve than did the lowest elevation leaves. The photochemical reflectance index was highly correlated with A_sat (r² = 0.99) and (r² = 0.96). In addition to contributing to our knowledge of the ecophysiology of paper birch along a steep environmental gradient, these results are further evidence of the usefulness of reflectance measures for the rapid and noninvasive detection of plant stress, especially when used in conjunction with direct measurements of photosynthesis.

Key Words: Betulaceae • Betula papyrifera • elevation • environmental gradient • leaf reflectance • light response curve • mountain paper birch • photosynthesis • stress physiology

This article has been cited by other articles:

				H. M. Poulos, U. M. Goodale, and G. P. Berlyn Drought response of two Mexican oak species, Quercus laceyi and Q. sideroxyla (Fagaceae), in relation to elevational position Am. J. Botany, May 1, 2007; 94(5): 809 - 818. [Abstract] [Full Text] [PDF]

				K. L. Castro-Esau, G. A. Sanchez-Azofeifa, B. Rivard, S. J. Wright, and M. Quesada Variability in leaf optical properties of Mesoamerican trees and the potential for species classification Am. J. Botany, April 1, 2006; 93(4): 517 - 530. [Abstract] [Full Text] [PDF]

				A. Thorhaug, A. D. Richardson, and G. P. Berlyn Spectral reflectance of Thalassia testudinum (Hydrocharitaceae) seagrass: low salinity effects Am. J. Botany, January 1, 2006; 93(1): 110 - 117. [Abstract] [Full Text] [PDF]