ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
MODELLING THE REGULATORY ROLE OF RESERVES ON SHOOT GROWTH |
| Author: | F. Zucconi |
| Keywords: | sprouting, June arrest, spur formation, shoot hierarchies, June drop, fruit abscission |
| Abstract:
Shoot growth generally experiences a period of stunting, soon after sprouting, termed “June arrest”. This occurs under conditions of optimal light, temperature, and soil moisture, suggesting that its control resides inside the plant. The event affects all shoots in an inverse relation to their vigour. Shoots recover in a few weeks, with the exception of the very weak ones, in which growth reduction is severe, leading to the development of spurs. A growth reduction episode also appears in fruit where, again, the larger ones resume growth while the smaller ones cease growth and abscise (June-drop). It has been suggested that such an overall growth reduction is due to the depletion of the reserves that support the start of growth in spring. To test the hypothesis, an experiment was set up with maiden trees, varying the amount of reserves per shoot. The results show the expected competition for growth among shoots. | |
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