Effects Of NO Treatment On The Respiration Of Different Fleshy Peach Fruit During Cold Storage

Peach(Prunus persica L.Batsch)cultivation areas are widely planted all over the world,and there are many varieties.As a typical climacteric fruit,peach has strong post-harvest respiration and short shelf life,but it is prone to chilling injury(CI)during cold storage.Therefore,it is important to explore regulate respiration,enhance fruit resistance,and extend the storage period of peach fruit.Due to the variety of peach fruit and the huge differences in the quality and respiration of different varieties,this results in different storage periods after harvest.This study used the very early-maturing,melting flesh type‘Chunxue'peach and the very late-maturing,stony-hard type‘Yingshuanghong'as the test materials and treated with different concentrations of NO.By observing the symptoms of CI and the changes in cell wall ultrastructure,measuring firmness,respiration rate,total soluble solids(TSS)content,electrolyte leakage,malondialdehyde content(MDA)and other quality indicators,testing glycolysis pathway(EMP),tricarboxylic acid(TCA)cycle pathway,pentose phosphate pathway(PPP),cytochrome oxidase pathway(CP),cyanide-resistant respiratory pathway(AP)key enzyme activities and gene expression changes,to explore the differences in postharvest storage quality of different fleshy peach cultivars and the effects of NO treatment on the respiratory metabolism pathways of peach fruit.This study clarified the regulation mechanism of NO on the respiratory metabolism pathways of different fleshy peach fruits,laying the foundation for the development of effective peach fruit storage methodsThe main research conclusions are as follows:(1)The melting flesh peach have low firmness and strong respiration rate.Its chilling injury symptoms are characterized by extravasation of juice and transparent flesh.Stony-hard peach have high firmness,low respiration rate after harvest,and no softening of the flesh,showing flesh browning,lignification and other chilling injury symptoms during cold storage.10?L·L^-1 NO treatment has the best effect,can delay fruit chilling injury,inhibit the decrease in firmness and TSS content,reduce respiration rate,electrolyte leakage,MDA content,and improve the storage quality of peach fruits.(2)NO treatment reduced the total respiration rate by reducing the respiration rate of EMP,TCA cycle and COX pathway of peach fruit.10?L·L^-1 NO treatment inhibited the respiration rate of EMP,TCA and CP pathway by reducing the expression level of PpGPI,PpSDH and PpCOX in peach fruit,inhibiting the activity of GPI,SDH and COX.(3)NO treatment induced the AP and PPP pathway of peach fruit to increase the antioxidant capacity,thereby delaying the chilling injury and improving the stress resistance.10?L·L^-1 NO treatment can increase the expression level of PpG-6-PDH,Pp6-PGDH and PpAOX,and enhance the activity of AOX and combined activity of G-6-PDH and 6-PGDH,thereby promoting the AP and PPP pathway and enhancing the antioxidant capacity and the resistance of the fruit to low temperature stress,and delaying the occurrence of chilling damage.(4)Different fleshy peach fruit have different responses to NO treatment.NO treatment has a great influence on the TSS content and respiration rate of‘Chunxue'peach,especially the respiration rate of EMP and TCA cycle,and has a great influence on the firmness of‘Yingshuanghong'peach,the respiration rate of PPP and AP pathway.The effects on chilling injury,electrolyte leakage,and MDA content are the same,and they all have a significant inhibitory effect.