Quantitative Studies on Root Development. III. Further Observations on Growth in the Seedling Phase

Abstract

The influences of light intensity, rooting medium, and the excision of various organs on the early phases of root growth in barley seedlings (cv. Piroline) were explored. The emergence of root axes was affected by light intensity and excision of roots, endosperm or shoot, but was not altered by the rooring medium. Elongation of the emerged axes was similarly responsive. The elongation rate of both the set of axes and individual axes fell wi4h time. The elongation rate of laterals was less than that of the axes and was sensitive to the excision of seedling organs. The data are discussed in relation to the hypothesis that the growth of the root system is determined by the availability of substrate.