The optimum temperature storage of anthurium
flowers is 12.5–20 C because they are very sensitive to
chilling injury (CI). CI is associated with the loss of membrane integrity which can be aligned to phenolic
oxidation due to polyphenol oxidase (PPO) activity, the enzyme responsible for tissue browning. The
increment of phenylalanine ammonia-lyase (PAL) activity, the enzyme responsible for phenols
accumulation, in response to chilling stress has been considered as defense mechanism to chilling
stress. In this study, the effects of 0, 1, 5, 10, 15 and 20 mM g-aminobutyric acid (GABA) treatment applied
by preharvest spraying or postharvest stem-end dipping (15 min at 20 C) on CI of anthurium
flowers (cv.
Sirion) stored at 4 C for 21 days was investigated. CI symptoms were accompanied by spathe browning
and increase in electrolyte leakage as well as malondialdehyde (MDA) content. GABA treatment at 1 and
5 mM by pre and postharvest treatment, respectively, delayed spathe browning and increases in
electrolyte leakage and MDA accumulation. The GABA treated anthurium cut
flowers exhibited
significantly higher PAL enzyme activity, associated with lower PPO activity. Higher PAL enzyme activity
in anthurium cut
flowers treated with GABA coincided with higher total phenol accumulation and higher
DPPH scavenging activity than control
flowers during storage at 4 C for 21 days. Also, proline content in
anthurium cut
flowers treated with GABA was significantly higher than control
flowers during storage.
These results suggest that GABA treatment can be used as a useful technology for enhancing tolerance of
anthurium cut
flowers to postharvest chilling injury by increasing total phenol and proline accumulation
and decreasing MDA content, and thus maintaining membrane integrity.