Absor??o e redistribui??o do nitrogênio aplicado via foliar em videiras jovens

摘要

The foliar application of nitrogen before the leaves senescence may be a strategy to increase the nutrient reserves in the perennial parts, being available in the beginning of the vegetative growth of the annual parts. The objective of this work was to estimate the uptake and redistribution of N applied by foliar way in young grapevines. The experiment was carried out in a greenhouse at EMBRAPA-Grape and Wine, Bento Gon?alves Southern Brazil. The cultivars used were Chardonnay and Riesling Italic grafted on rootstock 101-14 Mgt. It was cultivated one plant by vase with 10kg of soil Udorthent. The foliar application of N was parceled in three times during three successive days. It was applied 84,84mg N plant-1 using (15NH4)2SO4 . The plants were collected in seven times, during vegetative growth. The plants were fractionated in leaves, graft, carry-graft, thick roots (>2mm) and fine roots (<2mm), oven-dried, weighted, and analyzed N-total and 15N contents. The results showed that part of the N absorbed by leaves is redistributed and accumulated in the graft, rootstock, thick and fine roots, and later, redistributed for the new leaves, and the largest contribution of N for the new growth came from the roots of the plants. The foliar application of N before the senescence of leaves provides low absorption of N and small increase of the internal reservations of N in the perennial parts.