CARPELLARY OUTGROWTH DEVELOPMENT IN THE ENDOCARP OF GRAPEFRUIT, CITRUS-PARADISI (RUTACEAE)

The development and function of the carpellary outgrowth was investiga ted in grapefruit. Carpellary outgrowths were initiated 3 d postanthes is. By 7 d postanthesis, enlarged globose cells developed that were su btended by a parenchymatous stalk. Numerous Golgi, Golgi-derived vesic les, endoplasmic reticulum, mitochondria, and thickened cell walls pre sent in globose cells from 7 d to 3 mo postanthesis suggest that the c arpellary outgrowth was secretory in nature. Lectin-gold complex bindi ng indicated that the secreted product contained galactose and arabino se. Cessation of secretory activity, marked by protoplast degeneration , occurred between 3 and 5 mo postanthesis.