บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Hypoxia-induced biological changes indicate the presence of AC oxygen sensor in fruit and cut carnations

Theophanes Solomos, Prabodh Trivedi and Mehar Asif

Abstracts of 27th International Horticultural Congress & Exhibition (IHC 2006), August 13-19, 2006, COEX (Convention & Exhibition), Seoul, Korea. 494 pages.

2006

บทคัดย่อ

Hypoxia-induced biological changes indicate the presence of AC oxygen sensor in fruit and cut carnations

The most important aspect of hypoxia for prolonging storage life of certain detached plant organs in general and fruit in particular is retardation of the C2H4 climacteric o­nset.The length of the delay is saturable with respect to O2 concentration.In apples the delay occurs at O2 concentration below 6%.This is accompanied by suppression of the accumulation of ACS1 and ERS1 transcripts, both of which increase during the climacteric rise.Low O2 decreases rate of fruit ripening when their C2H4 climacteric has been initiated.This too is saturable with respect to O2 concentration since suppression of cellulases in climacteric avocado fruit is initiated when concentration of O2 drops below 10%.Hypoxia induces and/or enhances activity of anoxic proteins and this increase is also O2-dependent.In apples, the increase in accumulation of ADH transcripts is initiated at concentrations of O2 below 6%.In carnation petals ADH activity does not increase at O2 concentrations above 5-6%.Expression of the HMGR1 gene in apples increases with decreasing O2 concentration in a way similar to that of ADH.Its promoter contains hypoxic-response elements.The collective data indicate the presence of an O2 sensor that perceives the O2 concentration and when its concentration drops below a certain level, o­n the o­ne hand it suppresses the expression of developmentally regulated genes associated with tissue senescence, while o­n the other it enhances the expression of anoxic proteins. Indirect evidence indicates that the O2-sensing protein contains Fe, since Co Ni, elements that can replace Fe, enhance ADH activity in air.MCP retards the C2H4 climacteric but has no effect o­n the expression of the ADH anoxic gene.Neither does it inhibit the rise in ADH expression when applied together with low O2.