title: Associations between enzyme genotypes and dark respiration in perennial ryegrass, Lolium perenne L.
abstract: In this study, we determined whether relationships existed between dark respiration and genotype at five enzyme polymorphisms in perennial ryegrass, Lolium perenne L. Positive correlations were found between Q10of dark respiration and genotype at the phosphoglucomutase (PGM) and 6-phosphogluconate dehydrogenase (6PGD) loci. Plants doubly homozygous for the common allele at these loci were found to have Q10values 20% higher than those for double heterozygotes. In plants that were heat stressed for five consecutive days, Q10was found to be negatively correlated with apparent vigor after stressing. Individuals homozygous for PGM and 6PGD (with higher Q10values) exhibited more apparent damage following the stress than heterozygous individuals. Both PGM and 6PGD occupy positions in metabolism with regulatory potential. Although caution must be used in assigning causal relationships, the results suggest that specific forms of these enzymes are directly related to, or are correlated with, the determinants of respiratory efficiency in L. perenne.
authors.affiliation: Department of Environmental, Population, and Organismic, University of Colorado, Biology Campus Box 334, 80309, Boulder, CO, USA.
authors.forename: D Y
authors.initials: DY
authors.lastname: Rainey
authors.affiliation: Department of Environmental, Population, and Organismic, University of Colorado, Biology Campus Box 334, 80309, Boulder, CO, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Mitton
authors.affiliation: Department of Environmental, Population, and Organismic, University of Colorado, Biology Campus Box 334, 80309, Boulder, CO, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Monson
keywords: Dark respiration; Enzyme polymorphisms; Heat stress; Heterozygosity; Lolium perenne