Simple Sugars in Plants
Location: Outside U.S.
Date: Winter 2012-2013
Monosaccarides are soluble so cannot be a storage compound in plants. I have learnt that fructose is stored in fruits. Since fructose is also a monosaccharide, how it remains stored in fruits.
Thanks for the question. Yes, you are correct in that fructose (or other simple monosaccharides) are not an efficient storage form of energy in plants. You may have eaten some fruit that is not ripe. That fruit did not taste sweet since you are tasting starch which is a polymer of glucose. When fruit ripens, the starch gets converted to fructose.
I hope this helps. Please let me know if you have any more questions.
Although I am not a botanist, I think that the assumption that monosaccharaides cannot be stored in plants is not correct. The “Merck Index” listed glucose (a monosaccharide) as having some storage capacity in plant cells. You need to check this out.
Fructose is a monosaccharide produced in many plants, and found in many fruits. It is produced through photosynthesis. It is converted into glucose-fructose for storage as a disaccharide. The following may be helpful:
Anthony R. Brach, Ph.D.
Harvard University Herbaria c/o Missouri Botanical Garden
There are a number of examples where storage compounds are soluble in plants. The cells storing such compounds need intact membranes that contain the compounds in subcellular structures.
J. Tokuhisa Ph.D.
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Update: November 2011