Effects Of Nitric Oxide On Alternative Oxidasein Cyanide-resistant Respiration Of Postharvest Muskmelon

The regulatory mechanism of cyanide-resistant respiration is becoming a new focus of plant respiratory metabolism. However, there have been no reports on the effects of cyanide-resistant respiration by NO treatment of postharvest muskmelon.In this study, the effect of nitric oxide treatment on the postharvest quality, total respiration rate, respiration pathway and the key enzyme activity of ’Jia Shi’Muskmelon was studied. The full length of the key to Cyanide-resistant Respiration Pathway Alternative Oxidasein(AOX) c DNA were obtianed by RT-PCR and RACE tecnology, analysis the effect of NO treatment on the expression of AOX gene by q PCR tecnology, discussthe functions of the AOX gene in the cyanide-resistant respiration.The main results were as follows:( 1) Fruits of muskmelon were treated with 40 μL/L,60 μL/L,80 μL/L nitric oxide(NO)fumigation.The 60 μL/L NO treatment can better maintain Jiashi Muskmelon fruits hardness, it can slow the rise in the rate of weight loss; inhibition of soluble solids content, titratable the acid content; suppress the respiration of fruit rate, the production of ethylene; reduce the content of MDA; the 60 μL/L NO treatment is able to significantly induce SOD, POD, CAT activity increased, enhancing the antioxidant capacity of fruits in order to deal with the effect of the concentration of 60 μL/L NO is the best.( 2) 60 μL/L NO treatment decreased the respiratory intensity of “Jashi” Muskmelon. Not only significantly inhibit CP respiration of fruit rate reduce,but also induce AP respiration of fruit rate increased,and the respiration of fruit rate of EMP、TCA、PPP have a inhibitory effect.(3)Activities of COX、SDH、PHI、G6PDH �'� 6PGDH, enzyme activities were all reduced with the treatment of NO at different concentration. It appeared that NO regulated the respiratory intensity of respiratory pathway by regulating the enzyme activities of relevant-respiratory pathway. The effect of the concentration of 60 μL/L NO is the best.(4)Using the total RNA from Jiashi Muskmelon as the template, a partial AOX gene fragment(1300bp) was isolated and deposited in Gen Bank under Accession Number KM273124. AOX transcription factorexpression level was higher in the 60 ul/L NO treatment. The expression of Cm AOX was induced by NO treatment, suggesting that Cm AOX may be involved in positive regulation of the fruit storage.