myo-Inositol Metabolism in Lilium longiflorum Pollen: Uptake and Incorporation of myo-Inositol-2-H

Germinating Lilium longiflorum pollen absorbs and metabolizes myo-inositol-2-(3)H (MI-2-(3)H) with a pronounced lag when label is supplied from the beginning of germination. If MI-2-(3)H is given after 3 hours of germination, incorporation of labeled metabolic products into pollen tube polysaccharides is constant over a range of 0.56 mm to 2.78 mm MI. When MI-2-(3)H is supplied as a 0.5-hour pulse 3 hours after germination, the proper precursor-product relationship to tube wall polysaccharides is observed. Replacing 10% of the germination media with sigmatic exudate from a compatible cultivar hastens germination and tube elongation. Enhanced MI metabolism accompanies tube growth in this exudate-enriched media.