Articles
POLYAMINE BIOSYNTHESIS IN FLAVEDO OF ‘FORTUNE’ MANDARINS AS INFLUENCED BY TEMPERATURE OF POSTHARVEST HOT WATER DIPS
Article number
463_48
Pages
377 – 384
Language
Abstract
‘Fortune’ mandarins were submitted to postharvest hot water dips to verify the influence of this treatment on polyamine content in fruit flavedo.
Dip time was 3 minutes and temperatures tested were 44, 47, 50, 53, 56, and 59°C. Putrescine content in flavedo of untreated fruit was 2.66 μM· g-1 FW. This concentration increased proportionally to bath temperatures up to 6.43 μM· g-1 FW in fruit dipped at 59°C. Not so linear was the increase in spermidine from 0.064 μM· g-1 FW in control fruit to the maximum of 0.183 μM· g-1 FW in fruit treated at 53°C, with decreasing concentrations in fruit dipped at 56 and 59°C. Spermine content also increased from 0.007 μM· g-1 FW to 0.022 μM· g-1 FW in fruit treated at 47°C and ranged around this value at higher temperatures.
Treatment at 47°C was the most effective in reducing chilling injury index in fruit after 4 week storage at 2°C and 90–95% RH. Scald damage was observed with temperatures over 53°C. No correlation was found between polyamine content and chilling injury control, with slight differences for spermine.
Consequently, increases in polyamine levels appeared to be a response to heat stress, without having a specific role in inducing chilling resistance.
Dip time was 3 minutes and temperatures tested were 44, 47, 50, 53, 56, and 59°C. Putrescine content in flavedo of untreated fruit was 2.66 μM· g-1 FW. This concentration increased proportionally to bath temperatures up to 6.43 μM· g-1 FW in fruit dipped at 59°C. Not so linear was the increase in spermidine from 0.064 μM· g-1 FW in control fruit to the maximum of 0.183 μM· g-1 FW in fruit treated at 53°C, with decreasing concentrations in fruit dipped at 56 and 59°C. Spermine content also increased from 0.007 μM· g-1 FW to 0.022 μM· g-1 FW in fruit treated at 47°C and ranged around this value at higher temperatures.
Treatment at 47°C was the most effective in reducing chilling injury index in fruit after 4 week storage at 2°C and 90–95% RH. Scald damage was observed with temperatures over 53°C. No correlation was found between polyamine content and chilling injury control, with slight differences for spermine.
Consequently, increases in polyamine levels appeared to be a response to heat stress, without having a specific role in inducing chilling resistance.
Authors
M. Mulas, G. Gonzales-Aguilar, M.T. Lafuente, L. Zacarias
Keywords
Citrus reticulata, fruit, chilling injury, postharvest treatments, endogenous bioregulators
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