THE STIMULATION OF LEMNA MAJOR BY ORGANIC MATTER UNDER STERILE AND NON-STERILE CONDITIONS

Abstract

This paper gives the details of the successful sterilization of Lemna major (Spirodela polyrhiza) reported in Science Vol. 71, p. 268, 1930. The rate of reproduction of the sterile plant in in-organic solutions, with and without organic matter, is compared with the rate of the non-sterile cultures. Sterilization is accomplished by the use of bleaching powder and also K2HgI4 solutions. The plants are grown in cotton stoppered Erlenmeyer flasks in sunlight. In sterile solutions containing purified inorganic salts only, good growth was attained, and the rate of reproduction was perhaps faster than in non-sterile. Extracts of organic materials[long dash]manure, soil, alfalfa, etc.[long dash]which stimulated the growth of the non-sterile plant had no effect on the sterile cultures, or slightly depressed the rate of reproduction. Reinoculation from the non-sterile flasks produced stimulation as before. Pure cultures of bacteria, added to the flasks containing organic material, varied in their capacity to produce stimulation. A few pure organic compounds[long dash]urea creatinine, etc.[long dash]produced no increase in rate of growth, either sterile or non-sterile.