Micronutrient toxicity symptoms of seed geranium (Pelargonium × hortorum Bailey) `Ringo Scarlet' were experimentally induced by using 9 different concentrations of B, Cu, Fe, Mn, Mo and Zn in the fertilizer solution. Plants of 3-4 true leaf stage grown in peat-lite mix were constantly fed for 5 weeks with nutrient solutions containing 0.25, 0.5, 1, 2, 3, 4, 5, and 6 mM of each micronutrient. The control solution contained 20 uM B, 0.5 uM Cu, 10 uM Fe, 10 uM Mn, 0.5 uM Mo and 4 uM Zn. Visible foliar toxicity symptoms developed when the nutrient solution contained 2, 0.5, 5, 1, 0.25, and 0.5 mM, respectively, of B, Cu, Fe, Mn, Mo, and Zn. Reduction in dry matter yield was evident when 1 mM B, 2 mM Cu, 3 mM Fe, 2 mM Mn, 0.5 mM Mo, and 1 mM Zn were used in the fertilizer solution. Leaf chlorophyll contents decreased as Cu and Mn levels increased. Elevated levels of Fe increased tissue chlorophyll contents.
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