Water-deficit accumulates sugars by starch degradation--not by de novo synthesis--in white clover leaves (Trifolium repens).
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.
Lee
Bok-Rye
BR
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.
Jin
Yu-Lan
YL
Jung
Woo-Jin
WJ
Avice
Jean-Christophe
JC
Morvan-Bertrand
Annette
A
Ourry
Alain
A
Park
Chan-Woo
CW
Kim
Tae-Hwan
TH
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
D014867:Water; D002244:Carbon; D013213:Starch