Interrelationships between carbohydrate metabolism and nitrogen assimilation in cultured plant cells : I. Effects of glutamate and nitrate as alternative nitrogen sources on cell growth.

Suspension cultured sycamore (Acer pseudoplatanus L.) cells will grow with either nitrate or glutamate as sole nitrogen source. Under the particular culture conditions used, cell growth is nitrogen limited. Within the range of initial nitrogen concentrations used (7-14 mM), cell growth on nitrate or glutamate at the same initial nitrogen concentrations is generally comparable. The rate of cell growth on these two nitrogen sources is also comparable with that observed when urea or urea plus nitrate is the prime nitrogen source. Increased nitrogen concentrations result in proportional increases in the final yield of numbers of cells, soluble protein and fresh weight. Dry weight yield by contrast shows both an absolute and relative decline with increasing nitrogen concentrations. At higher initial nitrogen concentrations differences are apparent in the pattern of cell growth between nitrate and glutamate grown cells.