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Variation in leaf respiration in relation to growth and photosynthesis of Lolium
Author(s) -
WILSON D.
Publication year - 1975
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1975.tb01638.x
Subject(s) - photorespiration , biology , photosynthesis , respiration , lolium perenne , botany , compensation point , heritability , respiration rate , ecophysiology , dry matter , horticulture , agronomy , poaceae , transpiration , genetics
SUMMARY Six Lolium genotypes with contrasting apparent photorespiration and CO a compensation concentration, [C0 2 ] c , were compared for net photosynthesis, dark respiration, leaf starch accumulation, rate of leaf expansion and shoot regrowth. Plants were grown in day/night temperatures of 15/10 and 25/20 o C. There were significant (P < 0–05) differences between the genotypes in all these parameters. At 25/20 o C apparent photorespiration was correlated with [CO 2 ] c . Correlation coefficients, pooled from both temperature regimes, revealed that genotypes with high rates of net photosynthesis accumulated more leaf starch during light periods than genotypes with slow photosynthesis, but rates of leaf expansion and dry matter increase were only correlated, negatively, with dark respiration. Apparent photorespiration was negatively correlated with dark respiration. These findings suggest that attributes related to photorespiration such as [CO 2 ] c and O 2 uptake from CO 2 ‐free air in the light are unlikely to be useful selection criteria for growth of C 3 grasses, that net photosynthesis was probably not limiting growth and that maintenance respiration may have been an important determinant of genotypic differences in growth rate. Selections for slow and fast rates of dark respiration of mature leaves were therefore made at 8 and at 25 o C from within two different populations of L. perenne , S.23. This characteristic showed repeatabilities (broad‐sense heritability) of from 0–41 to o‐66. Six independent comparisons of simulated swards of the slow‐ and fast‐respiring selections were made under periodic cutting regimes, either in a growth room at 25 o C or in a glasshouse from August to May. Growth of all plots of slow‐respiring genotypes was consistently more rapid than that of the fast‐respiring, at 25 o C in the growth room, and during autumn and spring in the glasshouse. There was no difference in winter growth. The implications of these results for the use of gas exchange measurements as selection criteria in plant breeding programmes are discussed.