FLOWER ABSCISSION AND ANTHOCYANIN DEVELOPMENT IN CUT PHLOX FLOWER HEADS: EFFECT OF ETHYLENE INHIBITORS AND SUCROSE

Abstract

Phlox paniculata `John Fanick' produces long lasting, dense terminal flower heads and has potential as a specialty cut flower. Quality and postharvest display life of cut flower heads depends primarily on ethylene-induced flower abscission, flower bud opening, and maintenance and development of flower color during vase life. Late events, such as flower and leaf senescence may also be detrimental to flower quality. In the control treatment, the initial red-pink and purple flower color changes to violet blue in 3 to 4 days, and may lose >50% of initial anthocyanins. Incorporating sucrose (SUC) in the vase solution not only maintained >75% of the initial floral pigments, but also promoted opening of additional flowers and anthocyanin development. Although both ethylene biosynthesis (AOA, ReTain, a.i. AVG) and action inhibitors (STS, 1-MCP) delayed flower abscission, STS and 1-MCP were relatively more effective than AOA and AVG. As in the control, newly opened flowers remained very small when treated with ethylene inhibitors, did not develop red-pink color, and exhibited only shades of violet blue color. Sucrose antagonized the effect of ethylene inhibitors. As such, the flowers in SUC+ethylene inhibitors treatments enlarged in size and developed a reddish-pink blue color. However, the flower quality in SUC alone was much superior than those in SUC+ethylene inhibitors. These results indicate that ethylene inhibitors, alone and in combination with SUC, were not of any additional value in improving postharvest performance and display life of cut phlox flower heads.