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Effects of CO₂ enrichment on soluble amino acids and organic acids in barley primary leaves as a function of age, photoperiod and chlorosis

Permanent URL:
http://handle.nal.usda.gov/10113/15033
Abstract:
Responses of soluble amino acids and organic acids to either ambient (36Pa) or elevated (100Pa) CO₂ treatments were determined using barley primary leaves (Hordeum vulgare L. cv. Brant). Total soluble amino acids were increased 33% by CO₂ enrichment 9 days after sowing (DAS), but a decrease relative to the ambient CO₂ treatment was observed with increasing leaf age. Marked declines of glutamine and asparagine were observed under CO₂ enrichment, both diurnally and with advancing leaf age. Consequently, total soluble amino acids were 59% lower in the elevated compared to the ambient CO₂ treatment 17 DAS. It was likely that chlorosis in response to CO₂ enrichment negatively impacted soluble amino acid levels in older barley primary leaves. In contrast to the ambient CO₂ treatment, glutamine and most other soluble amino acids decreased as much as 60% during the latter half of a 12h photoperiod in primary leaves of 13-day-old seedlings grown under enhanced CO₂. Malate was decreased about 9 percent by CO₂ enrichment and citrate and succinate were increased by similar amounts when measured 9 and 13 DAS. Malate accumulation was also decreased about 20% by CO₂ enrichment on a diurnal basis. The onset of CO₂-dependent leaf yellowing had much less of an effect on organic acids than on soluble amino acids. This above results emphasized the sensitivity of N metabolism to CO₂ enrichment in barley. Increased levels of citrate and succinate in response to CO₂ enrichment suggested that the tricarboxylic acid cycle was upregulated in barley by CO₂ enrichment. In summary, organic and amino acid levels in barley primary leaves were dynamic and were altered by age, diurnally and in response to CO₂ enrichment.
Author(s):
Sicher, Richard C.
Subject(s):
Hordeum vulgare , barley , carbon dioxide , amino acids , organic acids and salts , photoperiod , chlorosis
Format:
p. 576-582.
Note:
Includes references
Source:
Plant science 2008 June, v. 174, no. 6
Language:
English
Publisher:
[Ireland]: Elsevier Science Ireland Ltd.
Year:
2008
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.