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

What's this?

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 Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Poulos, H. M. Articles by Berlyn, G. P. Search for Related Content PubMed Articles by Poulos, H. M. Articles by Berlyn, G. P. Agricola Articles by Poulos, H. M. Articles by Berlyn, G. P. Social Bookmarking                            What's this?

Drought response of two Mexican oak species, Quercus laceyi and Q. sideroxyla (Fagaceae), in relation to elevational position¹

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

ABSTRACT

To investigate the relationship between the altitudinal distribution of Quercus laceyi and Q. sideroxyla and their physiological responses to drought, we measured relative water content (RWC), water potentials (_predawn and _midday), photosynthesis (A_max), stomatal conductance (g), chlorophyll fluorescence (F_v/F_m), and spectral reflectance (400–1100 nm) five times during a 7 wk acute drought. Quercus laceyi was drought tolerant, while Q. sideroxyla was a drought avoider; Q. laceyi tolerated lower RWC (Q. sideroxyla = 54%, Q. laceyi = 44%), _pd (Q. sideroxyla = –2.6 MPa, Q. laceyi = –3.3 MPa), and _md (Q. sideroxyla = –4.5 MPa, Q. laceyi = –6.6 MPa). The F_v/F_m also declined first in Q. sideroxyla in wk 6, whereas F_v/F_m did not decline in Q. laceyi until wk 7. A_max and g fell in wk 4, 6, and 7 in drought seedlings of both species, suggesting a decline in CO₂ assimilation during the drought. Leaf spectral reflectance increased with time in response to decreases in leaf photosynthetic pigment concentrations in latter weeks of the drought. The results suggest a close association between the altitudinal distributions of these species and their adaptation to water stress.

Key Words: chlorophyll fluorescence • elevation gradient • Fagaceae • photosynthetic efficiency • Quercus • spectral reflectance • stress physiology • water relations

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				B. E. Mahall, C. M. Tyler, E. S. Cole, and C. Mata A comparative study of oak (Quercus, Fagaceae) seedling physiology during summer drought in southern California Am. J. Botany, April 1, 2009; 96(4): 751 - 761. [Abstract] [Full Text] [PDF]

				L. H. Fraser, A. Greenall, C. Carlyle, R. Turkington, and C. R. Friedman Adaptive phenotypic plasticity of Pseudoroegneria spicata: response of stomatal density, leaf area and biomass to changes in water supply and increased temperature Ann. Bot., March 1, 2009; 103(5): 769 - 775. [Abstract] [Full Text] [PDF]