THE IMPORTANCE OF INFLORESCENCE LEAVES IN FRUIT SETTING OF ‘SHAMOUTI’ ORANGE

Mixed inflorescence was found to be most important for ‘Shamouti’ orange fruit set.
The leaves in the leafy inflorescence were essential for a period of 1 to 1½ months after anthesis, and girdling served as only a partial substitute for the young leaves. ¹⁴CO₂ feeding experiments were conducted on one-year-old or younger leaves of an old ‘Shamouti’ tree in the field, 25 days after anthesis.

The ¹⁴C distribution pattern in the young flushes showed that fruitlets represent a stronger sink than young foliage on the same leafy inflorescence.
Although young leaves did photosynthesize at the same rate as one-year-old leaves, fruit borne on a leafless inflorescence adjacent to an old leaf, exerted a stronger sink than the fruit borne on a leafy inflorescence.
Nevertheless, such leafless inflorescences abscissed 2–3 months after anthesis.
Girdling of the branch changed ¹⁴C distribution in the leafy inflorescence, favoring the fruitlet.

It is proposed that young leaves play an important role in the mixed inflorescence, mostly at the time when they act as a sink and not as a source of photosynthates.

Fruit Set and Development, XXI IHC

Y. Erner, B. Bravdo

https://doi.org/10.17660/ActaHortic.1983.139.14