| Popis: |
Diphenylamine (DPA), an antioxidant widely used to control superficial scald in apples stored at low temperatures, reduced the chilling-induced pitting of green bell pepper (Capsicum annuum L.) fruit in a concentration-dependent manner up to 12 mM. Treatment was effective whether applied as a 2-min dip or injected into the seed cavity prior to storing peppers at 1° C for 6 or 8 days followed by storage at 20° C for an additional 2 days. Ethanol (5%), the solvent used to dissolve the diphenylamine, also reduced chilling injury of green bell peppers, but to a lesser extent than DPA. Changes in all of the chlorophyll fluorescence parameters were observed within 24 h following the exposure of green bell peppers to low temperatures, whereas visible manifestation of chilling injury was not observed until after the peppers had been exposed to several days of low temperatures. Diphenylamine reduced the chilling-induced decline in maximal chlorophyll fluorescence and increased the time taken for maximal chlorophyll fluorescence to occur and the size of the electron acceptor pool. If chilling injury results from oxidative stress induced by low storage temperatures, it is unlikely that chloroplasts were the site of production of active oxygen species in these green bell peppers since they were stored in the dark. The rapidity of chlorophyll fluorescence responses to low temperatures makes chlorophyll fluorescence analysis useful to distinguish between chilling-sensitive and chilling-resistant plant tissues, but does not measure the extent of chilling injury. |
Full Text from ScienceDirect