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NET PHOTOSYNTHESIS AND LEAF AREA INDEX RELATIONSHIPS IN SWARDS OF DACTYLIS GLOMERATA UNDER CONTRASTING DEFOLIATION REGIMES
Author(s) -
Vickery P. J.,
Brink V. C.,
Ormrod D. P.
Publication year - 1971
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1971.tb00640.x
Subject(s) - dactylis glomerata , interception , leaf area index , photosynthesis , agronomy , tussock , pasture , biology , environmental science , poaceae , botany , ecology
Net photosynthesis per unit area of ground surface was determined at saturating light energy levels in Dactylis glonwrata swards over a wide range of leaf area indices (LAI). The relationship between net photosynthesis and LAI was influenced by the particular defoliation regime to which the sward was subjected. In most instances net photosynthesis and LAI were linearly related, with defoliation regime influencing both the slope and intercept of the regression. However, a defoliation regime which left leaves below 3 inches (7.5 cm) resulted in a curvilinear relation. The net photosynthesis‐LAI relationships were compared with the DM production of the swards on which they were obtained. Differences in these relationships did not entirely explain the differences in sward yield. The significance of these findings is discussed with reference to the theories of light interception and pasture growth.