ISHS Acta Horticulturae 463: VIII International Symposium on Plant Bioregulation in Fruit Production
UNDERSTANDING THE ROLE OF PLANT HORMONE DURING DEVELOPMENT AND MATURATION OF CITRUS FRUITS THROUGH THE USE OF MUTANTS |
| Authors: | L. Zacarias, F. Alférez, D. Mallent, Ma. Teresa Lafuente |
| Keywords: | Abscisic acid, carotenoids, Citrus, ethylene, gibberellins, maturation, mutants |
| Abstract:
To study the role of abscisic acid (ABA) in the regulation of Citrus fruit development and maturation, a spontaneous bud mutation of Navelate orange, named Pinalate, has been characterized. Mutant fruits displayed a slow rate of degreening and the skin of mature fruit was yellow The carotenoid content from mature fruits of both genotypes were quantitatively different. At full color, total carotenoids were about 3 times lower in wild type fruits and the proportion of carotenes and xantophylls were 12% and B8% whereas in the mutant accounted for about 86% and 12%, respectively. Mutant fruit accumulated large amounts of the early carotenes, phytoene, phytofluene and ξ-carotene. These data indicated that the mutation in Pinalate have impaired ξ-carotene desaturase activity. ABA content in flavedo tissue of mutant fruit was also reduced and full colored mutant fruits contained about 20% of the content of this hormone than those of wild type. Application of GA3 to Pinalate mature-green fruits did not have any effect delaying fruit coloration. The rate of fruit degreening after treatment with an ethylene-releasing compound (ethephon) was accelerated and similar, as compared with untreated fruits, in both genotypes. Collectively, the results suggest that ABA plays an important role in the regulation of the rate of fruit coloration and the involvement of ethylene and ABA on the process appears to be through independent mechanisms. The potential role of gibberellins and their interaction with ABA are discussed. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
