iron distribution in shoot organs
iron uptake, Phaseolus vulgaris L., retranslocation of iron
Springer Online Journal Archives 1860-2000
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Abstract A study has been made on the effect of primary leaves on iron (Fe) distribution in the shoot. Bean (Phaseolus vulgaris L.) seedlings were precultured in nutrient solution with 8×10-5 M FeEDTA for 4 days, and then grown further with either 8×10-5 M FeEDTA (+Fe) or without Fe supply (-Fe) for another 5 days. Thereafter, both +Fe and -Fe plants were treated in three different ways: undisturbed; one primary leaf removed; or one primary leaf shaded, starting two hours before supply 59FeEDTA to the roots. The +Fe plants were supplied with 8×10-5 M 59FeEDTA, and the -Fe plants with only 1×10-6 M 59FeEDTA. After 1 to 8 hour uptake periods, plants were harvested and 59Fe in different organs was determined. Removal or shading of one primary leaf did not affect 59Fe uptake by roots and 59Fe translocation to the shoot in +Fe plants. In the -Fe plants, however, removal of one primary leaf decreased 59Fe uptake by roots, whereas shading of one primary leaf had no effect on 59Fe uptake but slightly enhanced 59Fe translocation from roots to the shoot. The quantity of 59Fe in primary leaves was positively correlated with quantity of 59Fe in the stem in the -Fepplants, but not in the +Fe plants. In both, the +Fe and -Fe plants, the quantity of 59Fe in the shoot apex was positively correlated with 59Fe in primary leaves. The results suggest that irrespective of the Fe nutritional status of plants, the source of Fe for the shoot apex is Fe retranslocated from primary leaves.
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