Iron and zinc absorption characteristics and copper inhibitions in cucurbitaceae |
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Authors: | John M. Swiader |
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Affiliation: | Department of Horticulture , University of Illinois , Urbana, Illinois, 61801 |
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Abstract: | Iron and Zn absorption, interactions, and Cu inhibitions were characterized in cucumber (Cucumis sativus L.), watermelon (Citrullus lanatus Thunb.), and pumpkin (Cucurbita moschata Poir.) by kinetic parameters Vmax and Km. Influx and Vmax values for Fe and Zn absorption decreased in each species as plant age increased. For the Michaelis constant, Km, Fe values in cucumber and watermelon and Zn values in watermelon and pumpkin were relatively unchanged with increased plant age. Km values for Zn absorption in cucumber and Fe absorption in pumpkin decreased as plant age increased. Among species, watermelon appeared to have a particularly effective uptake mechanism for Zn at low solution concentrations. Non‐competitive inhibition of Zn absorption by Fe (20, 50 uM) was indicated in each species. Iron uptake in pumpkin was inhibited non‐competitively by Zn (5, 10 uM), however no significant effects of Zn on Fe absorption were evident in either watermelon or cucumber. Copper (0.5, 1, 5 uM) inhibited uptake of Fe non‐competitively and Zn competitively in each species. |
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Keywords: | Cucumis sativus Citrullus lanatus Cucurbita moschata plant nutrition non‐competitive inhibition competitive inhibition |
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