The effect of cold stress on ethylene biosynthesis and sensitivity in cut lily ‘Marlon’

Abstract

Fresh cut lily flowers often have a long postharvest life and produce undetectable levels of ethylene. This changes after cold storage, when lilies produce a higher amount of ethylene with a very early leaf and then flower senescence. Such changes to postharvest physiology are likely ethylene-dependant, either due to a higher level of ethylene production or a change in ethylene sensitivity as a result of alteration in the expression of genes involved in the biosynthesis, perception and signalling of ethylene. Therefore, we investigated the transcriptional regulation of ethylene biosynthesis, perception, and signalling pathways in response to cold storage in the cut lily cultivar ‘Marlon’. Cut lily stems were treated as follows: 1) control (no treatments), 2) 1-Methylcyclopropene (1-MCP; an ethylene action inhibitor) (10 nL L−1), 3) ethylene (10 μL L−1), and 4) 1-MCP (10 nL L−1) + ethylene (10 μL L−1) for 12 h, thereafter, half of each treated group were cold stored at 5 °C in 12 h light/dark condition for 7 days. We assessed quality characteristics, ethylene production, and the expression of its biosynthesis, perception, and signalling genes. Ethylene and 1-MCP treatments had no effects on non-cold-stored plants. Cold storage led to much earlier leaf yellowing (from 8 to 4 days), and flowers senesced and abscised 3 days earlier. In cold-stored plants, flower senescence and abscission were hastened by ethylene and delayed by 1-MCP. These findings indicate that ethylene does influence flower senescence following cold storage but leaf senescence is under the control of other factors. Our results suggest that treatments that focus on ethylene blockers to prolong postharvest life in lilies will be effective for flowers but not leaves.