Osmoregulation, growth and sucrose accumulation in germinated Trigonella foenum‐graecum (fenugreek) seeds treated with polyethylene glycol

Abstract

Germinated seeds of Trigonella foenum‐graecum L. (fenugreek) were grown in water or in polyethylene glycol (PEG) solutions. After endosperm removal, the water relations, growth, dry weight, sucrose and reducing sugar content of the embryo were determined. Under water sstress conditions, water content and osmotic potential (π0) at saturation, growth and dry weight were lower than in non‐stressed controls. The reduction in dry weight indicated a lower uptake of solutes from the endosperm and the decrease in π0 was not accompanied by an increase in the amount of the accumulated solutes. It is suggested that embryos of stressed fenugreek seeds control osmotic potential by reduction of water uptake and that this results in reduction of growth. Embryos isolated from germinated seeds (“naked” embryos) were grown in water or in PEG solutions, with or without galactose (as an external solute source substituting for the endosperm). The results indicate that a decrease in the external solute did not account for growth reduction under conditions of water stress, and that decreased solute transport to the embryo may be important. The sucrose contents of “naked” embryos and of embryos from whole seeds were higher after PEG treatment, while reducing sugar contents were lower compared to non‐stressed controls. The increased sucrose accumulation may be due to decreased sucrose hydrolysis.