Contribution of the Pentose Phosphate Pathway and Glycolytic Pathway to Dormancy Breakage and Germination of Peanut (Arachis hypogaeaL.) Seeds

Abstract

Levels of glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate : NADPH oxidoreductase, E.C. 1.1.1.49) 6-phosphogluconate dehydrogenase (6-phospho-D-gluconate : NADP+ oxidoreduc tase, E.C. 1.1.1.44) and aldolase (fructose 1, 6-diphosphate, D-glyceraldehyde, 3-phosphate lyase, E.C. 4.1.2.13) were assayed in the seeds of genetically dormant and non-dormant pure lines of groundnut. In dormant lines cotyledons showed increased levels of activity of G-6-PDH and 6-PGDH during dry storage after-ripening. While the embryonic axis did not exhibit detectable levels of enzyme activities immediately after harvest, the activity started after a lapse of time during dry storage. When seeds of dormant lines were incubated with kinetin (6-furfurylaminopurine) a distinct increase in the levels of both the enzymes was observed. The levels of aldolase activity gradually decreased in the cotyledons and increased in the embryonic axis of both control and kinetin treated seeds during the period of after-ripening. Compared to control, kinetin treatment increased the aldolase activity in the embryonic axis and decreased it in the cotyledons. In non-dormant lines the activity of both the enzymes of PP pathway increased sharply both in the cotyledons and embryonic axis while aldolase activity decreased in the cotyledons and increased in the embryonic axis during germination i.e., from 24 h to 96 h of germination. Abscisic acid caused inhibition of enzyme activities to a large extent.