Submitted to: American Society of Sugarbeet Technologists
Publication Type: Abstract Only
Publication Acceptance Date: February 3, 2003
Publication Date: February 17, 2003
Citation: KLOTZ, K.L., CAMPBELL, L.G. COMPARISON OF SCUROSE CATABOLISM IN ROOTS OF THREE BETA VULGAR L GENOTYPES WITH DIFFERENT YIELD AND SUCROSE ACCUMULATING CAPACITIES. Abstract of Joint Meeting of International Institute for Beet Research and the AMERICAN SOCIETY OF SUGARBEET TECHNOLOGISTS. 2003. Abstract p. 61. Technical Abstract: Sucrose catabolism is a major determinant of sink strength in nearly all plants and affects sucrose partitioning to growing sinks as well as sink size and carbohydrate content. Three major enzyme families are responsible for sucrose catabolism in sugarbeet roots: acid invertase, alkaline invertase and sucrose synthase. Previous work suggested that sucrose synthase may have a role in sink strength and root size in sugarbeet. To examine this observation more thoroughly, sucrose catabolism was compared in three Beta vulgaris genotypes with varying capacities for root yield and sucrose accumulation. Soluble acid invertase, cell wall acid invertase, alkaline invertase and sucrose synthase activities were compared at five stages of root development in a fodder beet hybrid (high yield, low sucrose content), a commercial sugarbeet hybrid (typical yield and sucrose content) and the sugarbeet breeding line, L19 (low yield, high sucrose content). Sucrose, glucose and fructose concentrations and mass accumulation were also determined. Generally, sucrolytic activity was greatest in the high yielding fodder beet and lowest in the low yielding L19 breeding line at any stage of development. Nearly all sucrolytic activity for all genotypes was due to sucrose synthase activity. Sucrose synthase activity was the predominant sucrolytic activity at all the stages of development examined, and accounted for 90% or more of the total sucrolytic activity in fodder beet and sugarbeet roots by six weeks after planting and in L19 eight weeks after planting. Differences in sucrose concentration between genotypes were observed and these were inversely correlated with soluble acid invertase activity. The differences in sucrose concentration, however, were largely differences in water content. Only L19 exhibited a significant increase in sucrose concentration when differences in water content were taken into account.