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Crop Science Abstract -

Relationships Between Leaf Area Index and Apparent Photosynthesis in Alfalfa (Medicago sativa L.) and Ladino Clover (Trifolium repens L.)1


This article in CS

  1. Vol. 7 No. 1, p. 27-30
    Received: June 3, 1966

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  1. R. T. Wilfong,
  2. R. H. Brown and
  3. R. E. Blaser2



Experiments were conducted to study the relationship between LAI, light penetration, and apparent photosynthesis in alfalfa and ladino clover stands intercepting between 80 and 100% of the incident sunlight. LAI-light interception patterns for ladino clover and first growth alfalfa differed from those of second and third growths of alfalfa.

NAR decreased as LAI increased; the relation appeared to be curvilinear. This indicated that optimum LAI occurred over a broad rather than a narrow range. LAI-apparent photosynthesis curves for alfalfa remained constant above the initial optimum LAI, although the curve for clover appeared to decline slightly beyond this point.

Initial optimiuni LAI coincided with the LAI's that intercepted approximately 95% of the incident light, indicating that Pa was near maximum at this point. LAI higher than required to intercept 95% of the light showed little effect on photosynthesis in the LAI range of 2 to 6. Dark respiration rates per unit of leaf area decreased as LAI increased. This may partially explain the leveling off of the LAI-apparent photosynthesis curves at high LAI values.

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