Variability in Activities of Sucrose Metabolizing Enzymes in Relation to Sucrose Accumulation Among Parents and Their Progenies of Sugarcane

摘要

Variability studies on sucrose metabolizing enzymes in relation to sucrose accumulation have been done in stem tissues of parents and a set of ten progenies of the cross Co 89003 (early maturing) × Co Se 92423 (late maturing) during sugarcane development. Sucrose content increased from stem elongation stage to maturity stage in both parents and progenies. Sucrose concentrations of the progenies were intermediate between those of the parents at stem elongation stage. Reducing sugars content, i.e., glucose plus fructose continuously decreased with advancement of the growth of the stem in all the genotypes. Specific activities of sucrose synthase (SS) and sucrose phosphate synthase (SPS) peaked at ripening stage and declined thereafter in each of the parents and their progenies. Specific activity of soluble acid invertase (SAI) in stem was found highest at stem elongation stage and declined thereafter in all the genotypes. Unlike SAI, soluble neutral invertase (SNI) activity increased with cane maturation. No significant overall relationship was found between the specific activities of SS/SPS/SNI and sucrose accumulation. However, a significant nonlinear negative relationship (R2 — 0.643) between SAI and sucrose accumulation did exist over all genotypes. The difference in specific activities of SPS and SAI (SPS-SAI) and sucrose concentration were significantly positively correlated, showing a near hyperbolic relationship (R~2 = 0.495). Hence, this study may assist the sugarcane breeders in the selection of genotypes having higher capacity for sucrose accumulation and their maturity behavior under subtropical conditions.