Isolation and Physiological Studies on Three Isolates of Amphora (Bacillariophyceae)1

SUMMARY Three clones of the diatom Amphora were euryhaline, able to grow autotrophically at 160 lx (0.001 ly/min) and heterotrophically on glucose and fructose. Furthermore 2 clones grew on glutamate and feast extract. Light‐limited growth of individual clones was stimulated by glycerol, galactose, lactate, acetate, aspartate and asparagine, although mannose torn inhibitory at low and high light levels. The half‐saturation constant for growth of A. coffeaefomis var. perpusilla Grunow (Cleve) with glucose was 25 μM. Heterotrophic growth rate of this organism became saturated with respect to glucose at 0.5 mM.