Carbohydrate metabolism during the head formation of lettuce

Research Project

Project/Area Number	07456017
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Research Field	園芸・造園学
Research Institution	The University of Tokyo
Principal Investigator	SUGIYAMA Noboru The University of Tokyo, Graduate School of Agricultural and Life Sciences, Associate professor, 大学院・農学生命科学研究科, 助教授 (30012040)
Project Period (FY)	1995 – 1996
Project Status	Completed (Fiscal Year 1996)
Budget Amount *help	¥6,600,000 (Direct Cost: ¥6,600,000) Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000) Fiscal Year 1995: ¥5,500,000 (Direct Cost: ¥5,500,000)
Keywords	Head formation / Lettuce / Fructan / 結球現象 / 炭水化物
Research Abstract	Remobilization of carbohydrates accumulated in stem tissues was investigated by monitoring changes in carbohydrate types and quantities in leaves and stems during the growth of crisphead lettuce (Lactuca sativa L.var.Gokuwasesisuko). Fructose, glucose and sucrose were the main non-structural carbohydrates in leaves. No accumulation of fructan was detected in leaves, with the exception of wrapper leaves. On the other hand, fructan and sucrose were the dominant non-structural carbohydrates in stems, with fructose and glucose present at low concentrations. Fructans with a degree of polymerization (DP) 3 decreased at the latter stage of head formation, with a concomitantly increase in Fructans with a high DP.DP3-10 fructans increased or stayd constant at the latter stage of the head formation. Fructan accumulations was correlated with an increase in the ratio of stems to aerial parts in terms of dry matter. These results suggested that fructans accumulated in stem tissues are not hydrolyzed and translocated into head leaves.