Fig. 4.

Transfer of ¹⁴C from starch made during different days of N deprivation into TAG. (A) Changes in ¹⁴C levels in TAG. Parallel cultures of D. tertiolecta were pulse-labeled for 24 h with [¹⁴C]bicarbonate during different days of N deprivation. At the end of labeling, cells were washed and transferred to fresh N-deprived media containing 50 mM sodium bicarbonate. Samples were taken for lipid extraction and fractionation at the end of labeling and at the indicated times. The ¹⁴C levels in starch and TAG were determined as described in the Materials and methods. (B) Fractional daily production of starch and of the total TAG produced from starch until the eighth day, expressed as a percentage of the total (data taken from A). Total levels of starch and of TAG produced in 8 d are 1453 nmol C 10⁶ cells⁻¹ and 196.5 nmol C 10⁶ cells⁻¹ for starch and TAG, respectively (means ± SD of three independent experiments). (This figure is available in colour at JXB online.)