Abstract: Viable generative cells and sperm cells of Lilium davidii Duch. were successfully isolated and purified with osmotic shock method and Pereoll density gradient centrifugation. Total proteins were extracted from sperm cells, generative cells and leaves of L. davidii. Protein patterns were compared on two-dimensional-PAGE. There were apparently more protein dots on the gel from sperm cells than on that from generative cells, especially in the alkaline region. Viable leaf protoplasts were isolated with multi-enzyme mixture, followed by centrifugation. The plasma membrane proteins of sperm cells, generative cells and intact leaf protoplasts were compared, using NHS-biotin (N-hydroxysuccinimido-biotin) labeling method. Horseradish peroxidase labeled streptavidin and the sub-strate 4-Chloro-l-naphthol were used to detect membrane proteins during Western blotting. Two proteins with molecular weights of 46 kD and 50 kD were specific to the plasma membrane of sperm cells. These two sperm specific protein dots were also found on the two-dimensional gels. These proteins may play key roles in sperm-egg recognition in the fertilization process.

Key words: Lilium davidii, Sperm cell, Plasma membrane protein, Western blot, Two-dimensional polyacrylamide gel electrophoresis