Growth of Red Clover Pollen. III. Free Amino Acid Composition in Grains and Supplements to Culture Media¹

Samples of red clover ( Trifolium pratense L.) pollen were cultured in vitro or analyzed for 21 amino acids. Pollen rated at more than 50% in germination capacity had about twice as much gamma aminobutyric acid, glycine, isoleucine, leucine, ornithine, serine, tyrosine, glutamic acid, and phenylalanirie and less proline than pollen which germinated at less than 50%. Supplements of proline, glycine, and alpha aminobutyric acid to the medium enhanced germination of pollen from plants grown in the greenhouse but not from plants grown in the field. Tube elongation of pollen from plants in the greenhouse and field was enhanced by proline and alpha or gamma aminobutyric acid supplements to the medium.