PROOF OF THE ESSENTIAL NATURE OF COPPER FOR HIGHER GREEN PLANTS

Abstract

In connection with experiments reported in this journal' by A. L. SO-IMIER and the senior author one experiment was conducted to determine whether or not copper is essential to the higher green plants.In that experiment flax was used as the experimental plant, and a series of cultures wvas run in culture solutions containing no copper with a parallel series the same in all respects except that 0.125 ppm. of Cu was added in the form of CuSO,.The plants in the two series grew equally well until the time of blossoming arrived, when it was noted that those in the series without Cu bloomed much less than the plants in the other series, but particularly that no plant deprived of Cu produced any seed capsule or seed.Since there were many plants in each series, and since every plant receiving Cu produced many seeds it appeared that the results were so striking as not to be accidental.Nevertheless, the senior author decided to run an experiment with another type of plant before reporting on the results.It did not prove feasible to start such an additional experiment until last fall.At that time the experiment described below was begun, and barley