Effects of the ethylene binding inhibitor, 1-methylcyclopropene, on flue-cured tobacco (Nicotiana tabacum L.)
Zachary Taylor, W. David Smith and Loren Fisher
Thesis, Doctor of Philosophy (Crop Science), North Carolina State University. 119 pages. 2009.
2009
บทคัดย่อ
Three experiments were conducted from 2005 to 2008 to determine the effects of 1-methylcyclopropene (1-MCP) on harvest management of flue-cured tobacco. Treatments consisted of 1-MCP at a rate of 0.026 kg ai ha-1 and 0.0129 kg ai ha-1 applied at: 14 d prior to normal final harvest, 14 and 7 d prior to normal final harvest, 7 d prior to normal final harvest, and 7 and 1 d prior to normal final harvest in all three experiments.
The first experiment was conducted to determine if applications of 1-MCP could increase holding ability and ripening delay in flue-cured tobacco. Holding ability and ripening delay of flue-cured tobacco was not increased by applications of 1-MCP. Value per hectare, grade index, and yield were not affected by applications of 1-MCP, but were reduced when harvest was delayed from the normal.
The second experiment was conducted to determine if applications of 1-MCP could inhibit chemical senescence from applications of 2-chloroethylphosphonic acid in flue-cured tobacco at a rate of 1.68 kg ai ha-1 . Chlorophyll meter values were affected when 1-MCP was applied at 14 d alone and 7 d alone in both 2006 and 2008 at either location. Thus in these years and locations, two of the four 1-MCP treatments were effective at inhibiting chemically enhanced senescence from applications of 2-chloroethylphosphonic acid.
The final experiment was conducted to determine the effective concentrations of ethylene and 1-MCP evolving from leaf surfaces after applications of 1-MCP in flue-cured tobacco. Differences in ethylene concentrations suggest that 1-MCP was bound to the receptor site and by 8-hours, 75-97% of the ethylene concentration had evolved from the leaf tissue. Once 2-chloroethylphosphonic acid had been applied for 48 hours, chlorophyll content in all chemical treatments was significantly reduced from that of the non-treated control. These data suggest that 1-MCP potentially occupied ethylene-binding sites and that new binding site were generated to accept ethylene in the form of 2-chloroethylphosphonic acid, initiating enhanced chemical senescence.