Abstract
Using methods previously described, cultures of 2 clones of M. polymorpha were supplied with 10 nutrient solns. ranging in conc, from 1.83 to 0.01 atmospheres, of which soln. 5, with a cone, of 0.21 atm. and 0.0033 mols per liter, was opt. for vegetative growth[long dash]as judged by fresh and dry wts. and area. It contained 1.6 ml. KN03, 1.4 ml. Ca(NO), 1.2 ml. Mg(NO), 0.8 ml. KH2PO, and 1.6 ml. MgSO, each of a 0.5 M soln. per liter, and the usual micro-nutrients. The pH characteristics of these solns. are briefly discussed. Gemmae cups are most numerous on plants grown on soln. 4, and are produced on [female] and [male] plants in a ratio of 1 to 1.44[long dash]a lower ratio than in previous expts. Solns. with high salt cone, tended to kill the growing tips of plants and produced translucent thalli. Solns. low in salts favored the development of anthocyanin, numerous rhizoids, and a sturdy plant body.