Yellowing of broccoli is a crucial limiting factor for its commercial value and consumer acceptance during postharvest.In this study,the impacts of exogenous melatonin(MEL)on chlorophyll content and fluorescence,as we...Yellowing of broccoli is a crucial limiting factor for its commercial value and consumer acceptance during postharvest.In this study,the impacts of exogenous melatonin(MEL)on chlorophyll content and fluorescence,as well as ultrastructure and membrane lipid metabolism of chloroplasts in broccoli were investigated during postharvest.The results showed that MEL treatment(200 μmol L^(-1))maintained the chlorophyll content,chloroplast autofluorescence and integral structure,and reduced the level ofserotonin in the chloroplasts in broccoli.Also,MEL treatment inhibited the membrane lipid peroxidation of chloroplasts,as indicated by low levels of superoxide anion(O_(2)^(-)),hydrogen peroxide(H_(2)O_(2))and malondialdehyde(MDA),and high levels of endogenous MEL.In addition,the stability and fluidity of chloroplast membranes were also better maintained in the treated broccoli via increasing the contents of phosphatidylglyceroland(PG),monogalactosyldiglyceride(MGDG),digalactosyldiglyceride(DGDG)and unsaturated fatty acids as well as decreasing saturated fatty acid content and the activities of lipoxygenase(LOX)and lipase(LPS).Thus,the application of MEL facilitated the maintenance of chloroplast integrity,thus contributing to yellowing postponement and the extension of the storage life of broccoli.展开更多
Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.Therefore,advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a hig...Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.Therefore,advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI,proline metabolism,and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control),0.1 (MT1),and 0.2 mmol L^(-1)(MT2) melatonin solution for 30 min.The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis,such as pyrroline-5-carboxylate synthetase (P5CS),pyrroline-5-carboxylate reductase (P5CR),ornithine D-aminotransferase (OAT),P5CS2,P5CR2,and OAT3.Additionally,proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.Thus,melatonin treatment has regulated proline metabolism resulting in the accumulation of proline,subsequently contributing to enhancing the chilling tolerance of‘Keitt’mango fruit.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.32372408)the National Natural Science Foundation of China for Youth(Grant No.32102041).
文摘Yellowing of broccoli is a crucial limiting factor for its commercial value and consumer acceptance during postharvest.In this study,the impacts of exogenous melatonin(MEL)on chlorophyll content and fluorescence,as well as ultrastructure and membrane lipid metabolism of chloroplasts in broccoli were investigated during postharvest.The results showed that MEL treatment(200 μmol L^(-1))maintained the chlorophyll content,chloroplast autofluorescence and integral structure,and reduced the level ofserotonin in the chloroplasts in broccoli.Also,MEL treatment inhibited the membrane lipid peroxidation of chloroplasts,as indicated by low levels of superoxide anion(O_(2)^(-)),hydrogen peroxide(H_(2)O_(2))and malondialdehyde(MDA),and high levels of endogenous MEL.In addition,the stability and fluidity of chloroplast membranes were also better maintained in the treated broccoli via increasing the contents of phosphatidylglyceroland(PG),monogalactosyldiglyceride(MGDG),digalactosyldiglyceride(DGDG)and unsaturated fatty acids as well as decreasing saturated fatty acid content and the activities of lipoxygenase(LOX)and lipase(LPS).Thus,the application of MEL facilitated the maintenance of chloroplast integrity,thus contributing to yellowing postponement and the extension of the storage life of broccoli.
基金financially supported by the National Natural Science Foundation of China(32072280)。
文摘Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.Therefore,advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI,proline metabolism,and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control),0.1 (MT1),and 0.2 mmol L^(-1)(MT2) melatonin solution for 30 min.The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis,such as pyrroline-5-carboxylate synthetase (P5CS),pyrroline-5-carboxylate reductase (P5CR),ornithine D-aminotransferase (OAT),P5CS2,P5CR2,and OAT3.Additionally,proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.Thus,melatonin treatment has regulated proline metabolism resulting in the accumulation of proline,subsequently contributing to enhancing the chilling tolerance of‘Keitt’mango fruit.
