Articles
EARLY PEACH FRUIT DEVELOPMENT: INDOLE-3-ACETIC ACID CONCENTRATION IN SEEDS AND PERICARP OF FRUITS ON A SINGLE SHOOT
Shoots were excised from field-grown ‘Redskin’ trees beginning 40 days after full bloom.
Ethylene evolution was measured, indole-3-acetic acid (IAA) was quantified in the pericarp, and seed tissues of individual fruits from a shoot.
Although the population of ‘Jerseyglo’ flowers was pollinated on the same day, there was considerable variability in ethylene evolution, IAA concentration, and the size of the fruits on the same shoot.
The fruit fresh weights (FW) from the ‘Jerseyglo’ shoot ranged from 2.43–5.50 g and rates of ethylene evolution ranged from .21–1.07 n1 g-1 hr-1. Seed IAA concentration increased as fruit and seed FW increased, and ranged from 106 to 1572 ng g-1. As pericarp FW increased, IAA concentration decreased in this tissue.
The fruits from the ‘Redskin’ shoot had FW’s ranging from 4.80–7.09 g.
These fruits were more advanced in development than the ‘Jerseyglo’ fruits.
Fruit FW was negatively correlated with seed IAA concentration.
About 75% of the IAA found in the fruit was in the developing seed.
The pericarp IAA concentration was low, ranging from 2.8–6.5 ng g-1.
A peak in seed IAA concentration was coincident with the period of time when the endosperm was undergoing cytokinesis.
As the fruit continued to develop, pericarp IAA concentration declined until it reached the lowest level prior to the pit hardening stage.