| Summary: | 碩士 === 國立中興大學 === 農藝學系 === 87 === Sweetpotato cv Tainung 66 were planted in field, Wagner’s and sand pot, the plants were subjucted to 3 or 4-day waterlogging treatment at 90DAP. Potassium fer-tilizers（or potassium-enrichment nutrient）was applied before waterlogging treatment 、 after waterlogging treatment and whole growth period in order to explore whether potassium-enrichment nutrient application could melirate waterlogging injury of storage root, and to find out the cause of the waterlogging injury and some improved ways.
The yield of Tainung 66 storage root reduced by waterlogging treatment more serious than shoot in field, Wagner’s and sand pot experiments. Potassium-enrichment fertilizer application could partial recovery the yield of storage root lost caused by waterlogging injury. The best recovery effects of potassium-enrichment fertilizer application in field experiment, less in Wagner’s pot experiment and the worse in sand pot experiment. The same effects of organic-fertilizer enrichment application as potassium-enrichment nutrient application in field and Wagner’s pot experiment. The effects of nitrogen fertilizer application after waterlogging treatment on promoting regrowth of shoot are signifficant，not on growth of storage root.
The chlorophll content and Rubisco activity of Tainung 66 were decreased and glucose 、sucrose、starch accumulated in leaves after waterlogging treatment. The glucose 、sucrose、starch decreased after waterlogging treatment in storage root because of the route of translocation was inhibited. The effects of potassium-enrichment fertilizer applicaton was less on promotion of chlorophll content and Rubisco activity but beneficial on promotion of photoassimilates translocation. The results of 14C-labelling experiment indicated the application of potassium fertilizer promoted translocation of 14C out from leaves in sand grown waterlogging-sweetpotato plant, however most of 14C translocate to fiberous root, less to storage root.
In addition, the leakage of waterlogg-sweetpotato storage root increased because of acetaldehyde formation and free radical production. The MDA formation of storage root increased after anoxia treatment. Application of potassium fertilizer reduced the formation of MDA, but the promotion effects of SOD, AP and GR were not significant even inhibit the activity of these antioxidant enzyme. The reason is not clear.
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