ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
DIFFERENCES IN GROWTH AND DEVELOPMENT OF FUNCTIONAL XYLEM OF GRAFTED AND BUDDED SWEET CHERRY TREES |
| Authors: | M. Meland, M.E. Moe, O. Frøynes |
| Keywords: | Prunus domestica L., staining, hydraulic conductance, cultivars, rootstocks, grafting, budding, tree growth |
| Abstract:
Histological properties of the graft union between a rootstock and scion may provide a mechanistic explanation why dwarfing rootstocks are able to reduce the growth of the tree. In order to investigate the relationship between growth and the amount of functional xylem tissue of potted sweet cherry trees, an experiment was conducted during 2002-2003. One-year-old field budded and bench grafted (from greenhouse) sweet cherry trees of the cultivars 'Van', 'Ulster' and 'Lapins' in all combinations of the three rootstocks Prunus avium seedling, Colt and Gisela 5 were grown in pots for two growing seasons. After shoot extension had terminated, when trees were in full leaf in the second year following potting, the total growth of the different parts of the trees and the functional area using safranin staining were measured. The total mass production (tree dry weight, the length of two-year-old wood and number of leaves) was significantly larger in the budded trees. Similarly, the trunk cross sectional area was significantly larger 10 cm above and in the middle of the graft union, but not 10 cm below it. The Colt trees were the most vigorous followed by the seedling and Gisela 5. Minor differences between the different cultivars were registered. Xylem staining with aqueous safranin combined with quantitative image analysis showed that the rootstock stem had a higher proportion of stained functional xylem tissue than the scion stem. Sections taken in the middle of the graft tissue and 10 cm above showed that the proportion of stained tissue declined proportionally with the distance from the roots. The total area of stained stem xylem was larger for the two vigorous rootstocks compared to Gisela 5. Small differences were observed between cultivars and propagation methods. | |
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