|
Keywords
|
papaya, GABA, chilling injury, abiotic stress, proline, GAD
|
|
Abstract
|
The effect of g-aminobutyric acid (GABA) treatment at two concentrations (1 mM
or 5 mM) on papaya fruit stored at 4°C and 80%–90% relative humidity for 5
weeks was investigated. The application of GABA at 5 mM apparently inhibited
chilling injury, internal browning, electrolyte leakage, malondialdehyde (MDA),
hydrogen peroxide (H 2 O2 ), polyphenol oxidase (PPO), phospholipase D (PLD),
and lipoxygenase (LOX) activities of papaya fruit. Fruit treated with 5 mM GABA
enhanced the activities of ascorbate peroxidase (APX), catalase (CAT),
glutathione reductase (GR), superoxide dismutase (SOD), glutamate
decarboxylase (GAD), and phenylalanine ammonia-lyase (PAL). In addition,
GABA treatment significantly displayed higher levels of proline, endogenous
GABA accumulation, phenolic contents, and total antioxidant activity than the
nontreated papaya. The results suggested that GABA treatment may be a useful
approach to improving the chilling tolerance of papaya fruit by reducing
oxidative stress and enhancing the defense system.
|