Photosynthetic Photon Flux Influences Macroelement Weight and Leaf Dry Weight per Unit of Leaf Area in Prune Tree Canopies

in Journal of the American Society for Horticultural Science
Authors:
S. A. WeinbaumPomology Department, University of California, Davis, CA 95616

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S. M. SouthwickPomology Department, University of California, Davis, CA 95616

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K. A. ShackelPomology Department, University of California, Davis, CA 95616

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T. T. MuraokaPomology Department, University of California, Davis, CA 95616

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W. KruegerPomology Department, University of California, Davis, CA 95616

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J. T. YeagerPomology Department, University of California, Davis, CA 95616

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Abstract

The relationship between canopy position and foliage concentrations of several phloem-mobile and -immobile essential nutrients was determined over a 20-fold range of average incident photosynthetic photon flux (PPF) (50 to 1000 μmol·s−1·m−2) in 7-year-old prune (Prunus domestica L., syn. ‘Prune d’Agen’) tree canopies. Mineral weight per unit of leaf area (LA) increased with increasing PPF within the canopy according to the relationship N > Ca > Mg > K > P. Dry weight per leaf area (DW/LA) increased 3-fold over the range of light exposures sampled. Leaf nutrient concentration expressed as percent dry matter (DM) did not vary with PPF. Both DW/LA and leaf N/LA appear to integrate the light microenvironment at the canopy coordinates of leaves sampled and may be correlated with photosynthetic capacity. Thus, these parameters may have diagnostic value in orchard management and crop production.

Contributor Notes

Received for publication 20 Oct. 1988. This work was supported in part by the California Prune Board. We acknowledge R.M. Carlson, T.M. DeJong, I. Klein, and C. Rosen for critical reviews of this manuscript. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.

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