Author
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Sinclair, Thomas |
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SHEEHY, JOHN - IRRI, PHILIPPINES |
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Submitted to: Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/24/1999 Publication Date: N/A Citation: N/A Interpretive Summary: One important component frequently cited for contributing to the remarkable crop yield increases in the past 40 years has been the development of crop varieties with erect leaves. The widely held belief concerning the benefit of the erect leaves is that increased leaf angles improve the distribution of light in the crop canopy and thereby result in increased crop photosynthetic rates. Remarkably, there is virtually no experimental or theoretical evidence to support this belief. This short letter written by an ARS-USDA scientist in Gainesville, FL, presents an original hypothesis to explain the association between increasing crop yields and erect leaves. The basis for this hypothesis is the fact that increasing crop yields requires increasing amounts of nitrogen to be stored in the plant for later use when seeds begin to grow. Consequently, increasing leaf areas are required to store the accumulated nitrogen. Leaf angle must be increased to allow light to reach the leaves at the bottom of the canopy so that they may be retained for nitrogen storage. Therefore, high yield crops are predicted to require erect leaves not because of increased photosynthesis, but because of the need to sustain a large leaf area for nitrogen storage. Technical Abstract: None required for "letters" in Science. |
