Effect of modified and controlled atmosphere storage on enzyme activity and senescence of Dendrobium orchids

Abstract

This research investigated the effect of different atmosphere storage conditions on 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase enzyme activity; and senescence of cut Dendrobium orchid flowers. The atmosphere storage conditions under study were normal atmosphere, modified atmosphere packaging, and controlled atmosphere. Under the normal atmosphere, carbon dioxide (CO 2 ) and oxygen (O 2 ) concentrations were 0.03 and 21 %, respectively. For the modified atmosphere packaging, cut orchid flowers were wrapped in polypropylene film prior to filling with 5 % CO 2 and 2 % O 2 , while under the controlled atmosphere, CO 2 and O 2 concentrations were maintained at 5 and 2 %, respectively. The storage temperature and relative humidity were 13 °C and 95 %, respectively. The ACC synthase and ACC oxidase activity and ethylene-induced electrolyte leakage were determined and results compared. The controlled atmosphere substantially lowered ACC synthase and ACC oxidase activity and was effective in delaying senescence of cut orchid flowers, as indicated by the longest storage life of 28.33 days, followed by the modified atmosphere packaging (18.15 days) and normal atmosphere (11.67 days). The longer storage life enables suppliers of orchid flowers to efficiently manage the demand and supply and also provides exporters with new opportunities to expand into distant overseas markets. The novelty of this research lies in the use of different storage environments to investigate the senescence mechanisms at tissue level of Dendrobium orchid flowers in response to ACC synthase and ACC oxidase enzyme activity.

Effects of active and passive modified atmosphere packaging on biochemical properties of cut Dendrobium orchid flowers

“…According to Andrew et al . (2009) ; Poonsri (2020) , passive MAP, together with low temperatures, could effectively extend the shelf life of cut flowers ( Figure 2 ).

Figure 2 Effects of active and passive MAP on the physical appearance of cut Dendrobium Sonia orchid flowers after 9 days: (a) under normal atmosphere condition, (b) in PP-film passive MAP, (c) in PP-film active MAP.

…”

“…The lower respiration rates could be attributed to the modified atmosphere inside the packaging (higher CO 2 and lower O 2 ) due to the semi-permeability of plastic films ( Poonsri, 2020 ). According to Andrew et al.…”

“…The ethylene production rates of orchid flowers retained in active and passive MAP were significantly lower than under the normal atmosphere condition (p < 0.05), as shown in Figure 4 . The ethylene production of the control steadily increased and reached 13.22 ppm on day 6, which is the level of ethylene that induces wilting, abscission and senescence ( Rattanapanon and Boonyakiat, 2013 ; Poonsri, 2020 ). Due to the excessive ethylene levels, the average storage life of orchid flowers under the normal atmosphere was only 7.67 days.…”

“…The results could be attributed to higher CO 2 inside MAP, which attached itself to the receptor sites of plant tissues. Specifically, CO 2 competed for the receptor sites with ethylene ( Poonsri, 2020 ). In addition, the semi-permeability of plastic films altered the internal atmosphere (higher CO 2 and lower O 2 ), which reduced the ethylene production and ethylene action ( Brandes and Zude-Sasse, 2019 ; Kader, 2002 ; Andrew et al., 2009 ; Poonsri, 2021 ).…”

“…In addition, the semi-permeability of plastic films altered the internal atmosphere (higher CO 2 and lower O 2 ), which reduced the ethylene production and ethylene action ( Brandes and Zude-Sasse, 2019 ; Kader, 2002 ; Andrew et al., 2009 ; Poonsri, 2021 ). Specifically, the ethylene production was reduced as low O 2 inhibited the conversion of 1-aminocyclopropane-1-carboxylic acid (ACC) into ethylene ( Poonsri, 2020 ).…”