The Boron Nutrition of the Diatom, Cylindrotheca Fusiformis, Grown on Agar, and the Biological Activity of Some Substituted Phenylboronic Acids

Abstract

The boron requirement of the diatom Oylindrotheca fusiformis Reimann & Lewin, grown in liquid culture, was confirmed, Methods are described in which this requirement is also easily demonstrated on agar, when it is satisfied by 10-5M boric acid, Using this agar technique, the ability of various organic (and other) boron compounds to elicit a growth response on boron-deficient agar media was studied. Aqueous solutions of germanium dioxide were inactive. The results are discussed in relation to the various hypotheses regarding the relationship between the chemical structure and biological activity of boron compounds. The results obtained are consistent with the "complexing hypothesis" for the biological activity of borate.