Atmospheric CO sub(2) Enrichment: Kinetics of Chlorophyll a Fluorescence and Photosynthetic CO sub(2) Uptake in Individual, Attached Cotton Leaves

Gas exchange, leaf temperature transpiration, and chlorophyll-a fluorescence data were obtained in short- and long-term experiments to examine the response of mature, attached cotton leaves to atmospheric carbon dioxide enrichment. Ambient and enriched CO sub(2) values were 250 and 4000 mu l/l, resp...

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Bibliographic Details
Published in:Environmental and experimental botany 1994-01, Vol.34 (1), p.75-75
Main Author: Betsche, Thomas
Format: Article
Language:English
Subjects:
Gossypium hirsutum
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Summary:Gas exchange, leaf temperature transpiration, and chlorophyll-a fluorescence data were obtained in short- and long-term experiments to examine the response of mature, attached cotton leaves to atmospheric carbon dioxide enrichment. Ambient and enriched CO sub(2) values were 250 and 4000 mu l/l, respectively. Short-term results indicated that linear photosynthetic electron flow, nonphotochemical chlorophyll fluorescence quenching, and photochemical chlorophyll fluorescence quenching were not significantly affected by CO sub(2) enrichment. The long-term study results, however, were variable, with CO sub(2) uptake, transpiration, and chlorophyll fluorescence increasing and decreasing throughout the study period. Overall, the longer-term results suggested that exposure to elevated atmospheric CO sub(2) causes some perturbation at the metabolic level, leading to higher nonphotochemical chlorophyll fluorescence quenching, low leaf conductance, high leaf starch content, and a decline in ribulosebisphosphate carboxylase-oxygenase. These changes may be due to the fact that photorespiration declines in high-CO sub(2) concentrations while CO sub(2) fixation increases.
ISSN:0098-8472