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Relationship of Net Photosynthesis to Carbon Dioxide Concentration and Leaf Characteristics in Selected Peanut (Arachis) Genotypes¹

Authors: A. S. Bhagsari , R. H. Brown

  • Relationship of Net Photosynthesis to Carbon Dioxide Concentration and Leaf Characteristics in Selected Peanut (Arachis) Genotypes¹

    ARTICLES

    Relationship of Net Photosynthesis to Carbon Dioxide Concentration and Leaf Characteristics in Selected Peanut (Arachis) Genotypes¹

    Authors: ,

Abstract

Five genotypes, including two cultivars of Arachis hypogaea L. and three wild species of Arachis, were tested for their photosynthetic capacity at atmospheric CO2 concentrations and for photorespiration in CO2-free air. Photosynthetic response to CO2 concentrations in the range of 50 to 600 ppm was also tested. Diffusive resistance (DRH2O) of the adaxial surface of the five genotypes was measured with a diffusive resistance porometer. Several other leaf characteristics related to CO2 exchange were measured.

There was a linear increase in net photosynthesis (Pn) for four of the five genotypes as CO2 concentration was increased from 50 to 600 ppm. The increase in Pn of an A. hypogaea genotype from Tanganyika appeared to be progressively less at CO2 concentrations near 600 ppm. The florunner cultivar of A. hypogaea had the highest Pn at CO2 concentrations of 300 ppm and above; A. pintoi had the lowest. Photorespiration as measured by CO2 evolution into CO2-free air averaged about 4 mg CO2 dm -2 hr -1 and did not differ among genotypes. Dark respiration was higher in leaves of wild species than in the two genotypes of A. hypogaea.

Diffusive resistance of A. hypogaea, A. pintoi and A. sp. (glabrata?) leaves remained constant from 9 a.m. to 3 p.m. EST and then increased up to the last measurement at 10 p.m. The DRH2O of A. hypogaea and A. pintoi were similar during the daytime and ranged from 1.5 to 5.0 sec cm -1 between 9 a.m. and 3 p.m. A. villosulicarpa and A. sp. (glabrata?) had higher DRH2O values during the same time period, ranging from 5 to 12 sec cm-1. At 10 p.m. DRH2O of A. hypogaea was 84 sec cm-1 compared to only about 20 sec cm-1 for A. pintoi. Net photosynthesis of leaves of the five Arachis genotypes was not closely related to DRH2O nor leaf characteristics including chlorophyll content, stomatal frequency, leaf nitrogen content or specific leaf weight.

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Keywords: Arachis hypogaea, photorespiration, Chlorophyll, Groundnut

How to Cite:

Bhagsari, A. & Brown, R., (1976) “Relationship of Net Photosynthesis to Carbon Dioxide Concentration and Leaf Characteristics in Selected Peanut (Arachis) Genotypes¹”, Peanut Science 3(1), p.10-14. doi: https://doi.org/10.3146/i0095-3679-3-1-3

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Published on
01 Jan 1976
Peer Reviewed

Author Notes

1Contribution of the Department of Agronomy, University of Georgia, Athens, Georgia 30602.