CHANGES IN CARBOHYDRATES AND CARBOHYDRATE METABOLIZING ENZYMES DURINGTHE DEVELOPMENT, MATURATION, AND RIPENING OF BUTTERCUP SQUASH (CUCURBITA-MAXIMA D DELICA)

During this study, we divided the developmental growth pattern of butt ercup squash into three phases: 1) early growth, from flowering up to 30 days after flowering; 2) maturation, from 30 days until 60 days aft er flowering (or harvest); and 3) ripening, from 60 days (or harvest) until approximate to 100 days after flowering. Harvest occurred at 48 days after flowering. Fruit growth (expansion), starch, and dry matter accumulation were largely completed during early growth, and there wa s a progressive decline in the respiration rate. Extractable activitie s of acid and alkaline invertases, sucrose synthase, alkaline a-galact osidase, and sucrose phosphate synthase (assayed with saturating subst rates) were high initially but declined markedly during this phase. Gl ucose, fructose, and low concentrations of raffinose saccharides were present, but no sucrose was detected. During maturation, starch and dr y matter remained nearly constant and sucrose began to accumulate. Dur ing ripening, starch was degraded, sucrose synthase activity was signi ficant but relatively constant, sucrose phosphate synthase activity in creased, and sucrose continued to accumulate.