HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pearce, R. B. Articles by Blaser, R. E. Search for Related Content PubMed Articles by Pearce, R. B. Articles by Blaser, R. E. Agricola Articles by Pearce, R. B. Articles by Blaser, R. E.

Photosynthesis in Plant Communities as Influenced by Leaf Angle¹

Flats of barley were seeded at three different rates and tilted at 0°, 30°, and 60° from the horizontal. When the first leaf had developed the flats were returned to the horizontal for measurements of photosynthesis, light penetration, and leaf area index. This method produced flats with uniform leaf angles of 90°, 53°, and 18° at different leaf areas.

Results showed that differences in net photosynthesis, due to leaf angle, increased as leaf area index (ratio of leaf area to soil area) increased above two. The vertical leaves had a higher Pn and allowed more light to penetrate at high LAI's than horizontal leaves. Leaves at 90° required a leaf area index of 11 to intercept 95% of the light; 53° and 18° leaves intercepted 95% of the light at LAI's of 7 and 4.5, respectively. The mean extinction coefficients were 0.32, 0.45, and 0.60, respectively, for leaves 90°, 53° and 18° to the horizontal.

When data from these experiments were analyzed in equations proposed by Saeki to predict the net photosynthesis of a plant community, the predicted results closely approximated experimental results.

Key Words: light penetration • leaf area index • respiration

² Former Graduate Assistant (now Research Plant Physiologist, ARS, USDA, Beltsville, Md.), Former Associate Professor of Agronomy (now Associate Professor of Agronomy, Rice-Pasture Research and Extension Center, Beaumont, Texas), and Professor of Agronomy, Virginia Polytechnic Institute, Blacksburg.

Received for publication November 11, 1966.