(S)-(-)-limonene fumigation protects waxflowers (Chamelaucium spp.) from detrimental effects of ethylene on abscission of flowers/buds

摘要

Waxflowers are economically important native cut flowers in Australian floriculture industry. Postharvest flowers/buds abscissionon stems of waxflowers causes serious economic losses to the Australian waxflower industry. The effects of (S)-(-)-limonene inreducing the damaging effects of ethylene on abscission of flowers/buds in six varieties of Geraldton waxflowers ‘WX73’, ‘WXFU’,‘WX17’, ‘WX58’, ‘WX56’ and ‘Purple Pride’ were investigated in 2014 and 2015. All the experiments were conducted having fourtreatments. The flowers stems were fumigated with ethylene (10 μLL -1 ) for 24 h and (S)-(-)-limonene (1 μM) alone for 18 h and (S)-(-)-limonene fumigation followed by exposure to ethylene. Untreated sprigs served as control. All the six experiments were laid outby following two-factor factorial completely randomised design including the (4 treatments and 4 times) with three replications andthree stems were treated as an experimental unit. Cumulative abscission of flowers/buds was calculated for four consecutive daysfollowing 24 h of ethylene exposure. Fumigation with (S)-(-)-limonene (1 μM) for 18 h followed by exposure to 10 μLL -1 ethylenesignificantly reduced flowers/buds abscission as compared to ethylene treatment alone in all varieties except ‘WX17’. Meanflowers/buds abscission was significantly reduced when flower stems were fumigated with (S)-(-)-limonene followed by exposureto 10 μLL -1 ethylene (26.7%, 30.9%, 62.4%, 13.6 and 6.4%) as compared to those exposed to ethylene treatment alone (89.9%,82.0%, 77.4%, 85.9% and 68.8%) in ‘WX73’, ‘WXFU’, ‘Purple Pride’, ‘WX56’ and ‘WX58’ respectively. ‘WX17’ waxflower fumigatedwith (S)-(-)-limonene followed by exposure to 10 μLL -1 ethylene did not show a significant reduction in flowers/buds abscission ascompared to ethylene alone probably this genotype is more sensitive to ethylene because of their inherited trait. The resultssuggest that (S)-(-)-limonene act as an antagonist to ethylene action and consequently reduced flowers/buds abscission inwaxflowers.