Effects of different nitrogen sources in culture media on protoplast release from plant cell suspension cultures

Abstract

The release of protoplasts from alfalfa, soybean, flax, tobacco, wheat and rice cells grown in liquid media containing either nitrate, ammonium, L-glutamine or L-arginine as the sole nitrogen source was investigated. Growth of all cell types in nitrate medium was comparable or greater than that in other media but protoplast yield was poor. Alfalfa, soybean and flax cells grew better in nitrate medium supplemented with 2 mM NH 4 + than in medium containing only nitrate, and protoplast yield was also increased. Tobacco cells did not respond to this regime. Growth in ammonium medium was usually poor but protoplast yield was consistently as high or higher than for any other medium. Growth in L-glutamine medium was comparable to that in ammonium medium in all cases as was protoplast yield except for flax and wheat cultures where protoplast yield was as low as in nitrate medium. Arginine supported growth comparable to that in nitrate medium except in the case of tobacco culture where growth was poor. Protoplast yield from arginine-grown cells was higher than from nitrate-grown cells except in the case of soybean and tobacco cultures where yield was poor. The effect of nitrogen starvation for 3 days on protoplast yield was examined in wheat and rice cultures. Starvation was found to enhance the yield substantially when compared to that in nitrate medium. Results demonstrated a relationship between nitrogen metabolism and wall organization in these plant cells.