Effects of Shading and Defoliation on the Turnover of Root and Nodule Tissue of Plants ofTrifolium repens, Trifolium pratense, andLotus uliginosus

Abstract

White clover, red clover, and a lotus species were grown in glass-sided boxes and the effects of recurrent defoliation and of shading on the growth of roots and nodules were observed. With white clover, shading led to marked loss of both roots and nodules with little subsequent new growth. Under recurrent defoliation, however, the loss of roots and nodules was more than counterbalanced by new growth, leading to a rapid turnover of root and nodule tissue. With red clover, the loss of roots and nodules was slower. There was no regrowth in the shaded plants and little in the recurrently defoliated plants, leading to a smaller turnover of root and nodule tissue than with white clover. With lotus there was a rapid loss of nodules and some roots in both treatments, with only slight regrowth in the defoliated plants.