Increase in Free and Bound Abscisic Acid during Natural and Ethylene-induced Senescence of Citrus Fruit Peel

Abstract

Free and bound abscisic acid and neutral growth inhibitors were detected in citrus fruit peel using two bioassays and gasliquid chromatography. None of the inhibitor components seems to be directly associated with chloroplasts or chromoplasts in citrus fruit peel.Green, nonsenescent fruits contain mostly neutral inhibitors and relatively low amounts of free and bound abscisic acid. Upon harvest and storage in ethylene, 50 microliters per liter, both free and bound abscisic acid accumulate rapidly, attaining within 24 hours a level of 1 microgram per gram. After 48 hours bound abscisic acid reaches a much higher level than free abscisic acid. Fruits allowed to senesce on the tree follow a similar course of abscisic acid accumulation, attaiuing finally a 10: 1 ratio of bound to free abscisic acid.

Regulation of Senescence in Carnation (Dianthus caryophyllus)

“…Some (10) believe the effect of ABA to be mediated by ethylene, while others (6) consider it to be unrelated to ethylene. Conversely, ethylene has been demonstrated to promote a rise in the level of ABA (8,9,12).In this study, the effect of exogenous ABA and CO2 on ethylene production by cut carnation flowers was examined. enclosed in a 10-liter desiccator.…”

“…Hypobaric ventilation, which lowers ethylene to hyponormal levels within tissues, extended flower longevity and largely negated enhacement of senescence by abscisic acid. Supplementing hypobarically ventilated flowers with ethylene hastened senescence irrespective of abscisic acid treatment.Collectively, the data indicate that abscisic acid hastens senescence of carnations largely as a result of advancing the onset of autocatalytic ethylene production.Abscisic acid and ethylene (together or separately) promote senescence of flowers (1,2,9,12,14). The interaction of abscisic acid and ethylene in the control of senescence has been reviewed by Sacher (17).…”

“…Abscisic acid and ethylene (together or separately) promote senescence of flowers (1,2,9,12,14). The interaction of abscisic acid and ethylene in the control of senescence has been reviewed by Sacher (17).…”

Control endógeno y exógeno de la maduración externa de los frutos cítricos

“…Los niveles de clorofila, bajo este punto de vista, estarían determinados por un balance entre su síntesis y su degradación y el cambio de color ocurriría como consecuencia del desplazamiento de dicho balance hacia la disminución de la síntesis de clorofila (Jacob-Wilk et al, 1999). Durante el proceso de desverdizado, la piel de los cítricos acumula grandes cantidades de carotenoides oxigenados responsables de la coloración (Eilati et al, 1969b;Goldschmidt et al, 1973;Molnár y Szabolcs, 1980;Gross, 1981;Rodrigo et al, 2003Rodrigo et al, , 2006. La concentración y composición de éstos varía considerablemente entre las distintas especies y cultivares y depende de las condiciones ambientales (Gross, 1977).…”

“…Con respecto a las hormonas asociadas a la promoción de la maduración, se ha reportado que la aplicación de etileno induce un incremento del contenido total de ABA en el flavedo de los frutos cítricos (Goldschmidt et al, 1973, Lafuente et al, 1997. En este sentido, se ha probado que la expresión de la mayoría de los genes que codifican enzimas que actúan promoviendo la ruta de biosíntesis de carotenoides en el flavedo de los frutos, aumenta inducida por la aplicación de etileno durante la maduración Fujii et al, 2007), dando lugar al mencionado incremento de ABA.…”