1-Methylcyclopropene inhibits ethylene production and post-pollination changes of Dendrobium flowers

Abstract

Importance of the work: Stimulation of ethylene production by pollination causes early flower senescence and the initiation of many post-pollination developmental processes.
Objectives: To investigate the effects of 1-methylcyclopropene (1-MCP) on the ethylene production and post-pollination changes of Dendrobium cv. Sonia Bom #17 florets following pollination.
Materials & Methods: Open florets were treated with 1-MCP prior to pollination and monitored for ethylene production, the 1-aminocyclopropane-1 carboxylic acid (ACC) content, activities of ACC synthase (ACS) and ACC oxidase (ACO), gene expression, epinasty of florets, yellowing of the labellum, perianth venation and water-soaking of the floret tissues after pollination.
Results: Treatment of florets with 1-MCP prior to pollination delayed epinasty of florets, yellowing of the labellum, perianth venation and water-soaking of florets after pollination. In addition, the 1-MCP treatment reduced ovary growth, ethylene production, ACC content and the activities of ACS and ACO in pollinated florets. The ACC content and ACO activity increased more in the column plus ovary than in the perianth of pollinated florets while ACS activity in the column plus ovary increased less than in the perianth. The DenACO gene in the perianth of non-pollinated florets with the 1-MCP treatment was expressed more highly than that of pollinated florets with the 1-MCP treatment. The DenACO gene was expressed slightly throughout the study period in the column plus ovary of pollinated florets with the 1-MCP treatment.
Main finding: 1-MCP treatment delayed perianth senescence and decreased ethylene production, ACC. ACS and ACO in pollinated florets. The column was the likely source of ethylene production, while the increased ethylene production might have been partially due to an increase in DenACO gene expression.