THE PLANT CELL, Vol 3, Issue 3 219-223, Copyright © 1991 by American Society of Plant Biologists
Developmental Regulation Is Altered in the Calyx during in Vitro Ovary Culture of Tomato
B. K. Ishida
Western Regional Research Center, United States Department of Agriculture, Agricultural Research Service, 800 Buchanan Street, Albany, California 94710
To develop a system with which to study fruit ripening, in vitro ovary
cultures were initiated from tomato flowers. As reported previously
[Nitsch, J.P. (1951). Am. J. Bot. 38, 566-577], tomato fruit ripened after
6 to 7 weeks, but calyces swelled unexpectedly, lost their green color, and
gradually became red and succulent. Investigations were conducted,
therefore, to verify the occurrence of the ripening process in the calyx.
Ethylene production increased in both ripening fruit and red calyx, as did
tissue contents of its immediate precursor,
1-aminocyclopropane-1-carboxylic acid. In addition, an increase in the mRNA
of polygalacturonase [poly(1,4-[alpha]-D-galacturonide) glucanohydrolase,
EC 3.2.1.15], an enzyme that in tomato is present in large amounts only in
ripening fruit, was established in both ripe fruit and red calyx by RNA gel
blot analysis. Ultrastructural studies showed that the disruption of cell
walls in red calyx was indistinguishable from that occurring in ripe tomato
fruit. Thus, the developmental program of the calyx changed in several
aspects to resemble that of tomato fruit.
