Abstract
Pollen tube growth is very specific and called tip growth found only in some tissue. We found two exo-glucanases in the cell walls of lily pollen tubes and named LP-ExoI and LP-ExoII (Kotake et al. 2000). Since their activities were enhanced after pollen germination and these glucanases hydrolyzed laminarin, cello-oligosaccharide and cereal 1,3-1,4-β-glucan, the in vivo substrates were considered to be callose and cellulose. We analyzed the fragments of pollen tube hemicellulose and suggested the presence of 1,3-1,4-β-glucan. We also studied hemicelluloses of lily stigma and style through which pollen tubes pass. Neither 1,3-1,4-β-glucan nor callose was found in the tissues but glucomannan was the major constituent. From these results, substrates for LP-ExoI and II were not only callose and cellulose, but also 1,3-1,4-β-glucan in lily and there are no existence of callose and 1,3-1,4-β-glucan in both stigma and style.
