Patterns of axillary bud activity in white clover

The activity of white clover axillary buds was studied over a 13 month period in populations from set-stocked (S) and rotationally grazed (R) pastures. Bud activity in the field was observed and the viability of inactive buds was tested in the laboratory. R populations had significantly greater percentages of nodes bearing active buds, potentially active buds and roots. Two kinds of dormancy were identified in axillary buds. For much of the year buds at approximately 26% of nodes were prevented from growing, probably by a combination of correlative factors and the environmental conditions surrounding each bud-site. During spring, very few buds could be stimulated to grow; these buds were regarded as showing the second form of dormancy. The R population had a deeper but less prolonged 'spring dormancy'. The physiological basis and ecological significance of 'spring dormancy' are considered. Keywords white clover, dormancy, axillary buds