Ethylene production by three lily species and their response to ethylene exposure
H. John Elgar, Allan B. Woolf and Rod L. Bieleski
Postharvest Biology and Technology Vol: 16 Issue: 3 Pages: 257-267.
1999
บทคัดย่อ
Several lily cultivars from the three main groups were screened for response
to ethylene. The vase life of most Oriental hybrid and Lilium longiflorum
cultivars was unaffected by ethylene exposure. However, some Asiatic hybrids
showed minor responses, as noted for cultivars `Apeldoorn', `Goldena', `Elite'
and `Mona'. Endogenous ethylene production by all lily cultivars tested was
close to or below the limits of detection. CO2 production rates
during vase life of 7 days at 20°C varied from 0.5¯1.5
mol
kg-1 s-1, with Asiatic hybrids having rates in the upper
end of the range. No climacteric increase in ethylene or CO2
production was detected during 7 days at 20°C. Vase life of two Asiatic
hybrids (`Cordelia' and `Prato') was not affected by a wide range of ethylene
concentrations for varying durations, except at the highest concentration and
duration of ethylene exposure tested, when vase life was reduced by only about 10¯20%.
For those Asiatic lily cultivars responding to ethylene exposure, the main
effects were caused by high ethylene levels, with a reduced degree of flower
opening and percentage of buds which opened. Both these factors influence vase
life determination of stems, although quality of the individual flower buds was
often less affected by ethylene exposure, as evidenced by similar or extended
display life (the period flowers are open and of optimum quality) in
ethylene-treated flowers. Pre-treatment of stems with Chrysal®
or silver thiosulphate (STS) had little effect on the vase life of flowers
subsequently exposed to ethylene. Pre-treatment with 1-methylcyclopropene
(1-MCP) did not generally extend the vase life or improve flower quality of the
Asiatic or L. longiflorum cultivars tested, although exposure to
ethylene did reduce vase life of `Elite' and `Cordelia' by 1.5 days compared
with flowers pre-treated with 1-MCP. For `Cordelia', in vivo
1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity was high,
indicating that the enzymatic machinery for ethylene production is present even
although endogenous levels were difficult to detect. Generally, ethylene
exposure had little effect on cut flower quality or senescence of many of the
lily cultivars examined, even when present at high concentrations. This is at
variance with industry recommendations that lily flowers be treated with an
ethylene antagonist prior to presentation at auction.