Effect of MCP and 1.52 kpa oxygen on apple scald control and alphafarnesene biosynthesis
P. Trivedi, A. Matto and T. Solomos
Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-P-49. pp. 239.
2002
บทคัดย่อ
In the past 4 years we have studied the effects of MCP on scald control in “Granny Smith” “Rome” and “Red Delicious” apples, which are susceptible to scald, and in “Gala” and “Braeburn” cultivars, which are scald-resistant. Application of MCP and 1.52 kPa oxygen immediately after harvest inhibited development of the disorder during 180-220 days storage at 10 C followed by 10-15 days at room temperature in all cultivars. This was accompanied by a strong inhibition of the increase in alfa-farnesene and conjugated trienols. The effectiveness of MCP in controlling scald in “Granny Smith” apples was attenuated whenever its application was delayed. Furthermore, in “Red Delicious”, if the onset of the ethylene climacteric had been initiated at harvest the effectiveness of MCP was greatly diminished. We have cloned the genes of 3-methyl-3-hydroxyl glutaryl-CoA reductase (HMGR1) and the pharnesenyl-pyrophosphate synthase (FPPS) of the mevalonate pathway of *-farnesene synthesis. The expression of either of these genes does not appear to be inhibited by MCP despite the strong inhibition of the rise in a-farnesene content. 1.52 KPa of oxygen strongly enhances the expression of HMGR1. In fact the expression of HMGR1 parallels that of ADH at different O2 concentrations. Low oxygen does indeed inhibit the accumulation of FPPS transcrips.