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Abstract Detail

The Stress of Life with Light:: a Graeme Berlyn retrospective

Poulos, Helen Mills [1], Berlyn, Graeme [2], Goodale, Uromi Manage [3].

Using reflectance to measure the drought response of two Mexican oaks species,  Quercus laceyi and Q. siderolxyla (Fagaceae).

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 (Ψpredawn and Ψmidday), photosynthesis (Amax), stomatal conductance (g), chlorophyll fluorescence (Fv/Fm), and spectral reflectance (4001100 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%), Ψpd (Q. sideroxyla = −2.6 MPa, Q. laceyi = −3.3 MPa), and Ψmd (Q. sideroxyla = −4.5 MPa, Q. laceyi = −6.6 MPa). The Fv/Fm also declined first in Q. sideroxyla in wk 6, whereas Fv/Fm did not decline in Q. laceyi until wk 7. Amax and g fell in wks 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 wks of the drought. The results suggest a close association between the altitudinal distributions of these species and their adaptation to water stress.

Broader Impacts:
This discusses various measurements including spectral reflectance to find underlying ways to measure drought and drought resistance.

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1 - Wesleyan University , Environmental Sciences, Shamklin Laboratories 205, Wesleyan Universtiy, Middletown, CT, 06459, usa
2 - Yale University, School of Forestry and Environmental Sciences, Greeley Laboratories 375 Prospect St., New Haven, Connecticut, 06901, USA
3 - University of California at San Diego , San Diego , CA.

plant responses
Mexican oaks
Spectral reflectance.

Presentation Type: Symposium or Colloquium Presentation
Session: SY5
Location: 554/Convention Center
Date: Wednesday, August 4th, 2010
Time: 10:00 AM
Number: SY5006
Abstract ID:157

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