1-MCP prevents ultrastructural changes in the organelles of Dendrobium petals that are induced by exogenous ethylene

Ethylene is a plant hormone that causes flower senescence. Dendrobium flowers are sensitive to ethylene and ethylene can induce premature senescence depending on the cultivar and the ethylene concentration. Dendrobium 'Lucky Duan' is one of the most sensitive cultivars to ethylene exposure. Open florets of 'Lucky Duan' were subjected to ethylene, 1-MCP, or 1-MCP plus ethylene treatments and compared with an untreated control. Ethylene induced earlier development of color fading, drooping and venation in petals, whereas 1-MCP pre-treatment counteracted these changes. Under light microscopy, epidermal cells and mesophyll parenchyma tissue around the vascular bundles of petals treated with ethylene showed collapsed cells whereas 1-MCP pre-treatment counteracted this collapse. An scanning electron microscopy (SEM) study confirmed clearly that ethylene treatment caused the collapse of mesophyll parenchyma tissue around vascular bundles. Ultrastructural changes were also studied using transmission electron microscopy (TEM) and showed that ethylene treatment induced morphological changes in conjunction with disorganization of the plasma membrane, the nuclei, chromatin, the nucleoli, myelin bodies, multivesicular bodies, and mitochondria including changes in size and number, breakages of membranes, enlargement of intercellular spaces and disintegration. 1-MCP pre-treatment was observed to counter these changes that were induced by ethylene. The role of ethylene-induced ultra-structural changes in the different organelles was apparently associated with membrane damage.

Automated summary

Ethylene is a plant hormone that can cause flower senescence. Dendrobium flowers are highly sensitive to ethylene, and the concentration of ethylene can determine if premature senescence occurs. The cultivar 'Lucky Duan' is particularly sensitive to ethylene exposure. The study found that ethylene treatment induced color fading, drooping, and venation in the petals of 'Lucky Duan' flowers, while pre-treatment with 1-MCP counteracted these changes. The ultrastructural changes induced by ethylene, such as membrane damage and disorganization of different organelles, were also observed and were mitigated by 1-MCP pre-treatment.