Axillary Bud Development in White Clover in Relation to Defoliation and Shading Treatments

A period of growth under shade netting in the glasshouse allowed the cultivation of white clover stolons with an accumulation of undeveloped axillary buds similar to that often found on stolons from grass/clover swards. The subsequent capacity of these nodes to develop branches under different circumstances was investigated in three experiments. Removal of the laminae and petioles subtending sets of four buds along a stolon reduced the rate at which branches were initiated from the buds. Treatments in which petioles, or petioles plus laminae, were retained initiated branches more quickly. Shading the stolons reduced both the rate of initiation and the percentage of buds which developed, unless both petioles and laminae were retained. There was some evidence that conditions applied to individual buds may act in the same way as the same conditions applied to sets of four buds and that illuminated nodes may depress the performance of neighbouring shaded notes. Fewer buds developed at older nodes than at younger nodes during the summer, but during the autumn younger buds initially developed more slowly than older buds. This suggests that buds can develop at a younger nodal age in summer than in winter. When leafless stolons were cut up into component internodes buds developed faster than on intact stolons, provided the bud was located at the end of the internode nearest the main stolon growing point. If the bud was at the other end, branch development was slower than on intact stolons. The results are discussed in relation to clover growth in sward conditions.