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Abstract

Rapid ripening of mango fruit limits its distribution
to distant markets. To better understand and perhaps
manipulate this process, we investigated the role of plant
hormones in modulating climacteric ripening of ‘Kensington
Pride’ mango fruits. Changes in endogenous levels of
brassinosteroids (BRs), abscisic acid (ABA), indole-3-acetic
acid (IAA), and ethylene and the respiration rate, pulp
firmness, and skin color were determined at 2-day intervals
during an 8-day ripening period at ambient temperature
(21 ± 1�C). We also investigated the effects of exogenously
applied epibrassinolide (Epi-BL), (?)-cis, trans-abscisic
acid (ABA), and an inhibitor of ABA biosynthesis, nordihydroguaiaretic
acid (NDGA), on fruit-ripening parameters
such as respiration, ethylene production, fruit softening, and
color. Climacteric ethylene production and the respiration
peak occurred on the fourth day of ripening. Castasterone
and brassinolide were present in only trace amounts in fruit
pulp throughout the ripening period. However, the exogenous
application of Epi-BL (45 and 60 ng g-1 FW)
advanced the onset of the climacteric peaks of ethylene
production and respiration rate by 2 and 1 day, respectively,
and accelerated fruit color development and softening
during the fruit-ripening period. The endogenous level of
ABA rose during the climacteric rise stage on the second day
of ripening and peaked on the fourth day of ripening.
Exogenous ABA promoted fruit color development and
softening during ripening compared with the control and the
trend was reversed in NDGA-treated fruit. The endogenous
IAA level in the fruit pulp was higher during the preclimacteric
minimum stage and declined during the climacteric
and postclimacteric stages. We speculate that higher levels
of endogenous IAA in fruit pulp during the preclimacteric
stage and the accumulation of ABA prior to the climacteric
stage might switch on ethylene production that triggers fruit
ripening. Whilst exogenous Epi-BL promoted fruit ripening,
endogenous measurements suggest that changes in BRs
levels are unlikely to modulate mango fruit ripening.

Item Type:	Article
Authors/Creators:	Zaharah, SS and Singh, Z and Symons, GM and Reid, JB
Keywords:	Mangifera indica L., Brassinosteroids, Ethylene, Abscisic acid, Auxin, Respiration, Fruit ripening, Climacteric
Journal or Publication Title:	Journal of Plant Growth Regulation
ISSN:	0721-7595
Item Statistics:	View statistics for this item

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