Light as an ecological factor and its measurement

The Effect of Prolonged Shading on the Light Saturation Curves of Apparent Photosynthesis in Sun Plants.

“…The physiological classifications "sun" and "shade" plants are convenient, however, and perhaps should not be discarded. Accordingly, the authors feel in agreement with the views expressed by Blackman and Wilson (2) and Shirley (7), that plants should be arranged into sun and shade types on the basis of their ability to survive in a given light environment rather than on the basis of the light saturation curves of their leaves.…”

“…Leucine-C"4 0.18 0.16 0.11 * Amino acid incorporation by intact leaves, attached to the plant, was measured as described previously (7) following application of 10 micromoles (1,000,000 cpm) to the leaf surface. Leaves were treated with biuret or biuret plus urea five days before application of the amino acid.…”

Secondary Succession on the Piedmont of New Jersey

“…A second supposition, advanced by Shirley (1945) is that pioneer woody species such as red cedar rarely cast shade dense enough to preclude invasion of other species, but their shade and root competition may markedly reduce the growth of all but the most tolerant species. Lutz (1928) considers that ".…”

The Effect of Reduced Light Intensity on the Aerial and Subterranean Parts of the European Bindweed

“…The contributions to the role of light made by MACDOUGAL (18), , THATCHER (26), COMBES (10), RoSE (21), SHANTZ (23), GARNER and ALLARD (12), GOURLEY (13), GOURLEY and NIGHTINGALE (14), SCHULTz and THOMPSON (22), LUBIMENKO and KARISNEV (17), BATES and ROESER (7), IWANOFF and KOSSOWITSCH (15), WEAVER and CLEMENTS (28), TYSON (27), CLEMENTS and LONG (8,9), and SHIRLEY (24,25) The reduction in the amount of aerial growth in the control from 1,700.9 in 1937 to 276 grams in 1940 no doubt was due to the fact that the roots became matted and caused a local competition since the area was not cultivated.…”