TOTAL POLYSACCHARIDE CONTENT OF DEVELOPING POLLEN IN 2 ANGIOSPERM SPECIES

The PAS reaction was used to stain total insoluble polysaccharides in whole pollen grains of anthers of Borago officinalis and Lycopersicum peruvianum from early microspore to ripe pollen stage. Total polysacch aride content was quantified with a microdensitometer: in Borago offic inalis values showed two peaks, one during the microspore and the othe r during the binucleate stage; in Lycopersicum, there was a single pea k during the latter stage. In both species total polysaccharide conten t decreased markedly in the last stage of pollen development before an thesis, when starch was hydrolysed and the polysaccharide reserves of the pollen transferred to the cytoplasm. Pollen grain volume was also determined at the various stages. It was found to increase, though wit h a different pattern in the two species, and to decrease before dehis cence. The results are discussed in terms of cytoembryological data of pollen grain development.