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This article in CS

  1. Vol. 34 No. 1, p. 108-113
    Received: Jan 29, 1993

    * Corresponding author(s):
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Leaf Anatomy of Two Lycopersicon Species with Contrasting Gas Exchange Properties

  1. Hirut Kebede,
  2. Bjorn Martin ,
  3. James Nienhuis and
  4. Gretchen King
  1. Dep. of Horticulture, Univ. of Wisconsin, Madison, WI 53706



Lycopersicon pennellii (Cor.) D'Arcy possesses greater drought resistance and higher water use efficiency (WUE) than the domesticated tomato L. esculentum Mill. A previous report suggested three restriction fragment length polymorphism markers for whole plant WUE. This study identifies species differences in anatomical, biochemical, and physiological characteristics of leaves related to leaf gas exchange and whole plant WUE, which can later be tested with the molecular markers. Lycopersicon pennellii exhibited 29% lower stomatal frequency, more even distribution of stomata between the upper and the lower leaf surfaces, and a 54% thicker leaf with 31% greater air space volume relative to total leaf tissue volume than L. esculentum. Trichomes were fewer, but longer, and the ratio of air exposed mesophyll surface area relative to external leaf area was 41% greater for leaves of L. pennellii. However, this species contained 13% less chlorophyll and had 11% lower ribulose-l,5-bisphosphate carboxylase/oxygenase (rubisro) activity per unit leaf area than L. esculentum. The mean stomatal resistance (r8) was greater and substantially less variable among leaves of L. pennellii, but those leaves of L. pennellii and L. esculentum that had the same rs also operated at the same photosynthesis rate (A) and WUE. Therefore, differences in and WUE among the two tomato species could be fully explained by contrasting stomatal properties. Either the differences in individual leaf anatomical, biochemical, and physiological characteristics negated each other and did not substantially alter A and WUE, or the expression of the characters was linked to r8 in the same way in both species.

Published with the approval of the Director, Oklahoma Agric. Exp. Stn. as J-6414. Supported by U.S. Dep. of Energy grant no. DE-AC03-88ER80656.

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