| Abstract: | Onyia, G. O. C. and Gahan, P. B. 1985. A quantitative cytochemicalstudy of glutamate and glucose-6-phosphate dehydrogenase activitiesduring chilling injury in tubers of Dioscorea rotundala Poir.—J.exp. Bot. 36: 1249–1256. The response of glucose-6-phosphate dehydrogenase and glutamatedehydrogenase activities in healthy Jamaican Dioscorea rotundalatubers and those chilled at 3 ?C for 1,2,3,4, and 7 d at 70%r.h. were assessed by quantitative cytochemical assays. Bothenzymes in chill-damaged tuber tissues showed a substantiallyhigher activity than did those of the healthy tubers. An early,sharp increase in the response of the NADP-tetrazolium reductasesystem of damaged tuber tissue was significantly higher (P =0.001) than that of healthy tubers or those chilled but ableto recover. This response may be used as an early marker ofchilling injury in the yam tuber. Key words: Dioscorea rotundata Poir, quantitative cytochemistry, yam tuber, glucose-6-phosphate, dehydrogenase, glutamate dehydrogenase, NADPitetrazolium reductase |
