Biochemical stuides on the development of aril browning inpomegranate
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Date
40729
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Publisher
University of Agricultural Sciences GKVK, Bangalore
Abstract
Aril browning (AB) in pomegranate is a physiological disorder free of
external symptoms. Browning of aril starts with a dark dot on the aril
and spreads further to the entire aril. The incidence is at first observed at
50% fruit maturity near the calyx end just under the skin. Present
studies showed that AB incidence was higher in panicles with increasing
number of fruits and in fruits located on the lateral shoots as compared
to those on main shoots. Fruits exposed to sun showed lesser incidence.
AB incidence also increased with fruit maturity. Biochemical studies
revealed that sugars, TSS, starch and pH were higher in AB affected aril
as compared to healthy arils whereas anthocyanin, polyphenols, titrable
acidity, protein and ascorbic acid were less in AB affected aril. Enzyme
activities like amylase, total dehydrogenase activity in seed were reduced
in seed of AB affected aril compared to healthy whereas enzyme activity
like polyphenol oxidase was more in seed of AB affected aril as compared
to seed of healthy aril. Healthy arils showed higher moisture content and
the seed higher percentage and faster rate of germination as compared to
seed of AB affected aril, revealing that seed of AB affected aril had lost
moisture leading to reduction in seed viability. Field experiments with
growth regulators showed that GA3 treatment reduced incidence of AB
and PBZ treatment increased the incidence of browning as compared to
control. These findings indicated that the development of AB in
pomegranate is a result of combination of many factors like interfruit
competition, biochemical and physiological changes in aril during fruit
growth.