ONTOGENIC CHANGES IN PHOTOSYNTHETIC CARBON-REDUCTION CYCLE METABOLITES AND ENZYMES OF SUCROSE METABOLISM IN BRASSICA-CAMPESTRIS PODS

Rate of net CO2 exchange (P(N)), changes in the activities of the key enzymes of sucrose and fructose-2,6-bisphosphate (F-2,6-P2) synthesis and levels of certain metabolites of the photosynthetic carbon reducti on (PCR) cycle were determined in pod wall of Brassica at different st ages of pod development. P(N), activities of sucrose-P-synthetase (SPS ) and fructose-1,6-bisphosphatase (FBPase) and the contents of 3-phosp hoglycerate (3-PGA), ribulose-1,5-bisphosphate (RuBP), glyceraldehyde- 3-phosphate (Gly-3-P), dihydroxyacetone phosphate (DHAP) and uridine d iphosphoglucose (UDPG) increased upto 21 d after anthesis followed by a continuous decrease until maturity. However, the content of fructose -6-phosphate (F-6-P) started decreasing only after 28 d of anthesis. C hanges in F-2,6-P2 content were closely associated with the changes in F-6-P-2-kinase activity rather than with F-2,6-P2ase activity.