title: Water-deficit accumulates sugars by starch degradation--not by de novo synthesis--in white clover leaves (Trifolium repens).
abstract: Labeling 13CO2 in steady-state condition was used to estimate quantitative mobilization of recently fixed carbon or stored sugar during water-deficit in white clover (Trifolium repens L.). Water-deficient gradually decreased leaf-water parameters and total amount of recently fixed carbon. Amount of 13C incorporated into glucose, sucrose and soluble sugars fraction rapidly decreased after 3 days of water-deficit treatment. In contrast, the previously stored soluble sugars significantly increased after 5 days of water-deficit with a coincidence of significant decrease in starch concentration. A highly significant (P < or = 0.001) relationship between the decrease in leaf-water potential caused by water-deficit and the increase in ratio of soluble sugar/starch concentration was observed in water deficit-stressed plants. The data indicate that soluble carbohydrate accumulated by water-deficit treatment is mainly because of the hydrolysis of previously stored starch rather than to de novo synthesis.
authors.affiliation: Institute of Agricultural Science and Technology, BK21 Research Team for the Control of Animal Hazards using Biotechnology, College of Agriculture & Life Science, Chonnam National University, Buk-Gwangju P.O. Box 205, Gwangju 500-600, Korea.
authors.forename: Bok-Rye
authors.initials: BR
authors.lastname: Lee
authors.forename: Yu-Lan
authors.initials: YL
authors.lastname: Jin
authors.forename: Woo-Jin
authors.initials: WJ
authors.lastname: Jung
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Avice
authors.forename: Annette
authors.initials: A
authors.lastname: Morvan-Bertrand
authors.forename: Alain
authors.initials: A
authors.lastname: Ourry
authors.forename: Chan-Woo
authors.initials: CW
authors.lastname: Park
authors.forename: Tae-Hwan
authors.initials: TH
authors.lastname: Kim
mesh_terms: D018533:Biomass; D050260:Carbohydrate Metabolism; D002244:Carbon / Q000378:metabolism; D003681:Dehydration; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism*; D054046:Plant Stomata / Q000502:physiology; D018526:Plant Transpiration; D012995:Solubility; D013213:Starch / Q000378:metabolism*; D013312:Stress, Physiological; D029921:Trifolium / Q000378:metabolism*; D014867:Water / Q000378:metabolism* / Q000502:physiology
chemical_list: D014867:Water; D002244:Carbon; D013213:Starch