© 1994 Heron Publishing—Victoria, Canada
Partitioning of photoassimilates in avocado (Persea americana Mill.) during flowering and fruit set
Susan F. Finazzo (1), Thomas L. Davenport (1, 2) and Bruce Schaffer (1)
1. Tropical Research and Education Center, University of Florida, IFAS, 18905 S.W. 280 Street, Homestead, FL 33031, USA / 2. Author to whom correspondence should be addressed / Received May 12, 1992
Summary
To assess competition for photoassimilates among developing inflorescences, fruitlets and vegetative shoots in avocado (Persea americana Mill.), the distribution of recent photoassimilates was examined before and during flowering, fruit set, and the transition
from sink to source of developing vegetative shoots. Mature leaves, located proximal to developing reproductive organs, and
developing leaves, located distal to those organs, were exposed to a one-hour pulse of 14CO2. Translocation of radiolabeled assimilates was monitored over time and among organs. Overall distribution of assimilates
was dependent on dry mass of tissues regardless of organ type. Flowers and fruitlets did not demonstrate greater sink strength
than non-autotrophic leaves. Organs receiving assimilates were in phyllotactic alignment with source leaves. Photoassimilates
were never limiting, although flower and fruitlet abscission occurred during and long after this competitive period. Carbohydrate
availability was sufficient to support the growth of both developing fruitlets and leaves during early stages of reproductive
development, and it did not limit fruitlet growth or stimulate fruitlet abscission.
Keywords:
abscission, carbohydrates, phyllotaxis, sink strength.
