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Cyclitol galactosides in embryos of buckwheat stem–leaf–seed explants fed D-chiro-inositol, myo-inositol or D-pinitol

Published online by Cambridge University Press:  22 February 2007

Janet M. Ma
Seed Biology, Department of Crop and Soil Sciences, 617 Bradfield Hall, Cornell University Agricultural Experiment Station, Cornell University, Ithaca, NY 14853-1901, USA
Marcin Horbowicz
Seed Biology, Department of Crop and Soil Sciences, 617 Bradfield Hall, Cornell University Agricultural Experiment Station, Cornell University, Ithaca, NY 14853-1901, USA Research Institute for Vegetable Crops, Skierniewice, Poland
Ralph L. Obendorf*
Seed Biology, Department of Crop and Soil Sciences, 617 Bradfield Hall, Cornell University Agricultural Experiment Station, Cornell University, Ithaca, NY 14853-1901, USA
*Correspondence: Fax: +1 607 255 2644 Email:


Crop seeds accumulate soluble carbohydrates as part of their maturation process. In legume seeds, the major soluble carbohydrates are sucrose and its galactosides raffinose, stachyose and verbascose. In buckwheat (Fagopyrum esculentum Moench) seeds, the major soluble carbohydrates are sucrose and galactosides of d-chiro-inositol, named fagopyritols. This study was conducted to determine changes in soluble carbohydrate accumulation in embryos of buckwheat seeds after feeding solutions containing the free cyclitols D-chiro-inositol, myo-inositol and d-pinitol to stem–leaf–seed explants. Feeding D-chiro-inositol to explants resulted in a fourfold to fivefold increase in the accumulation of free d-chiro-inositol, fagopyritol A1 and fagopyritol B1 in embryos of mature seeds, but resulted in 30% less embryo dry weight compared to the control treatment without cyclitols. Feeding myo-inositol to buckwheat explants increased d-chiro-inositol in leaves and increased accumulation of fagopyritol A1 and fagopyritol B1 fivefold in embryos, fagopyritol A2 and fagopyritol B2 fourfold; fagopyritol A3 and fagopyritol B3 were also detected, with no reduction in accumulated embryo dry weight. Feeding d-pinitol to buckwheat explants resulted in accumulation of free d-pinitol in mature embryos, but not galactopinitols. D-Pinitol, galactopinitol A and galactopinitol B were not detected in embryos from explants fed solutions without d-pinitol. Feeding d-pinitol also resulted in reduced D-chiro-inositol accumulation by buckwheat seeds. The results indicate that myo-inositol may be the precursor to d-chiro-inositol synthesis, and fagopyritols accumulated in response to d-chiro-inositol availability in the embryo. We suggest that increasing myo-inositol in buckwheat maternal tissues may be an effective means to enhance the accumulation of D-chiro-inositol and fagopyritols in seeds, compounds that may be beneficial for the treatment of non-insulin-dependent diabetes mellitus.

Research Article
Copyright © Cambridge University Press 2005

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