Effects Of Exogenous Hydrogen Sulfide And Nitric Oxide Treatment On The Cold Resistance Of Postharvest Banana Fruits

Banana is a typical subtropical fruit,which is loved by the masses for its soft and delicate taste.However,bananas are easy to be subjected to low temperature stress in the storage process,and it is easy to cause cold damage at 0-8?.Cold damage has also become one of the most serious problems in the transportation,storage and processing of bananas.In recent years,H₂S and NO play an important role in the process of plant growth and development and abiotic response.However,there are few studies on the cold resistance of exogenous H₂S and NO to low temperature stress of banana fruits.This experiment using NaHS and SNP respectively as the H₂S and NO donor,exogenous H₂S is studied and the availability of nitric oxide?NO?,as an important signal molecule of postharvest bananas the physiological regulation and the quality of the fruit and the effect of NaHS found 1 mM and 2 mM SNP can reduce the damage to the cells of banana fruit at low temperature,maintaining high antioxidant enzyme activity,and promote the enzymes increase.Further research shows that exogenous H₂S treatment can cause the increase of endogenous H₂S content in banana fruits,and exogenous NO treatment can stimulate the increase of endogenous NO content in banana fruits,significantly improving the damage caused by low temperature to banana fruits.At the same time,the role of NO inhibitor in post-harvest storage and preservation of banana fruits was studied,and the important role of NO in alleviating the low temperature stress of banana was further clarified.This study provides an important theoretical reference for exploring the application of H₂S,NO and other signal molecules in the field of fruit and vegetable preservation.The main research results are as follows:?1?Exogenous hydrogen sulfide and nitric oxide treatment can promote the accu mulation of endogenous NO and endogenous H₂S contents in postharvest banana fruits during cryopreservation.At the same time,it can significantly reduce the cold damage symptoms of banana fruits,enhance the hardness,maintain the color,slow down the increase of MDA content,Maintain membrane integrity so as to improve the ability of bananas to resist cold damage.?2?Exogenous hydrogen sulfide and nitric oxide treatment can improve the enzymatic and non-enzymatic antioxidant capacity of postharvest banana fruits during cryopreservation.Exogenous H₂S and NO treatment can improve the activity of antioxidant enzymes?APX,CAT,POD,SOD,etc.?and enhance the scavenging ability of banana's own reactive oxygen species.Meanwhile,exogenous H₂S and NO treatment can promote the accumulation of non-enzymatic antioxidants in post-harvest banana fruits during cryogenic storage,enhance the activity of GR enzyme,promote the accumulation of GSH content,effectively delay the reduction of AsA content,and achieve the purpose of enhancing the resistance to low temperature.?3?Treatment with exogenous hydrogen sulfide and nitric oxide can improve theaccumulation of secondary metabolites in postharvest banana fruits during cryopreservation.By promoting the accumulation of proline and polyphenols to alleviate the low temperature stress,thus enhancing the cold resistance of bananas.