Foliar absorption and translocation of Zn-65 in balady orange plants

Greenhouse experiment was designed using Zn So4 as a single element or in a mixture of 'Zn SO4 + Fe SO4' at rates of 0.5 and 1.0% of these compounds. Different solutions were adjusted at PH 6.0 and Tween-20 at 0.5% (V/V) was added. The prepared solutions were labelled with carrier-free Zn-65. In a complete randomized design with three replicates orange seedlings two-year old were arranged. Labelled solution, in small droplets, were added onto upper surface of certain leaves (middle leaves) of seedling. Retained Zn-65 in the treated leaves with Zn SO4 alone was significantly higher than in leaves sprayed with a mixture of Zn, Mn and Fe sulphates. Upward and downward translocation of Zn-65 was highly related to its absorption through treated leaves and the translocation rate of upward direction was more pronounced than downward. Total absorption of Zn-65 was higher with Zn SO4 than with the mixture. Utilization percent of foliar application of Zn was significantly decreased as the rate of Zn SO4 increased from 0.5 to 1.0% either alone or in combination with Fe and Mn sulphates. Moreover, it was also reduced due to the presence of and Mn with Zn the spray solution with Zn SO4. In particular, 0.5% in soy solution realized the highest utilization and was efficient for supplying for orange plants with Zn. 3 tabs