Postharvest losses of phosphorus and chloride from leaves on mature vines have not been recorded - in previous experiments leaf sampling either ceased at harvest, or leaves frosted and fell before further sampling could be undertaken. What is unusual was the lack of remobilisation of magnesium, an element typically regarded as being mobile in plant tissues. The persistent accumulation of the other elements noted here is in line with their limited mobility in phloem - the vascular vessels in which nutrients and metabolites are transported out of plant tissues. These figures represent an upper limit of the amounts of nutrient able to be recycled from leaves, as nutrients can be leached by rain from senescing leaf tissue towards the end of the season, as well as being returned to the vine. Nevertheless, the results suggest that nutrients remobilised from leaves may be an important component in the vine's nutrient equation and that their legacy lives on, as it were, once the leaves have died.
Error bars represent a standard deviation either side of the concentration mean.
The concentration and net accumulation of macro- and micronutrients in leaves from fruiting canes during the 7 weeks prior to leaf fall. New Zealand Ltd. All rights reserved. Reproduction in whole or in part in any form or medium without express written permission of The Horticulture and Food Research Institute of New Zealand Ltd is prohibited.