NITRATE PREFERENCE IN HAEMATOCOCCUS AS CONTROLLED BY STRAIN, AGE OF INOCULUM, AND pH OF THE MEDIUM

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Abstract
The green alga haematococcus was tested for nitrate uptake in the presence of ammonium. Preference for the nitrate ion was controlled by initial pH of the medium and by age of the culture inoculum.Critical age and initiai pH for H. pluvialis Flotow, Cambridge U. strain 34/1a and for H. lacustris (Girod.) Rostaf., Indiana U. strain 294, were different. When inocula consisted of cells in log phase of growth, cultures of H. pluvialis preferred ammonium in medium that was pH 7.0. Only a small percentage of H. lacustris cultures preferred ammonium and only when the medium was as acid as pH 4.8. Increased age of the inoculum decreased sensitivity to pH of the culture medium.Nitrate uptake in H. lacustris was less sensitive to external pH and seemed to be more exclusive than in H. pluvialis.