Influence of pH On 2,4-Dichlorophenoxyacetic and Acetic Acid Activity in Chlorella.

Publisher Website
Google Scholar
Abstract
The concentration of un-dissociated 2,4-D in the bathing medium which produced 50% inhibition of photosynthesis in C. pyrenoidosa increased slightly over the range from pH 4.0 to pH 5.5. Similar determinations for acetic acid showed an increasing amount of undissociated acid required between pH 3.97 and pH 5.0 and a decreasing amount between pH 5.0 and pH 7.42. The amount of acetate anion increasing O2 uptake by 20% decreased slightly over the range from pH 4.0 to pH 7.55. Inhibition of photosynthesis by both 2,4-D and acetic acid appeared to be closely related to the concentration of undissociated molecules in the bathing medium, whereas the stimulation of O2 uptake by acetic acid appeared to be related to the concentration of the acetate anion in the bathing medium.