UTILIZATION OF NITRATE BY CELLS OF HETEROTROPHIC AND MIXOTROPHIC CULTURE OF GLYCINE-MAX L

We studied the effect of NO3- concentration and the presence of NH4+ o n growth, dark respiration, and photosynthetic O2 evolution, and on th e ratio between uptake on NO3- and sucrose by hetero- and mixotrophic soybean tissue cultures. Growth is shown to be controlled to a greater extent by the level of carbon supply than by nitrogen supply. Growth activity was inhibited only when nitrogen was totally absent in the nu trient medium. The concentration of NO3- and presence of NH4+ did not affect the rate of dark respiration, but exerted significant influence on the rate of photosynthetic O2 evolution per unit of raw mass. Reca lculation of the O2 evolution rate per unit of chlorophyll present in the cultures did not reveal such influence of the concentration of NO3 - and presence of NH4+. Uptake of NO3- is shown to depend not only on the level of carbon supply, but also on the mode of nutrition callus c ulture, strengthening of nitrogen metabolism occurring in cells of mix otrophic as compared with heterotrophic culture.