GROWTH CHARACTERISTICS OF PERENNIAL RYEGRASS

Abstract

Mature perennial ryegrass plants in pastures persist through the asexual reproduction of the tiller. Leaves are initiated from the flanks of the tiller stem apex. Generally, two leaves arc growing on a tiller at any one time. New tiller buds may arise from the axils of mature leaves depending on environmental conditions. Flowering results from a physiological change at the stem apex, which then produces a seed head but no further leaves, eventually resulting in the tiller dying. This phenomenon and other environmental changes result in marked seasonal trends in ryegrass tiller .densities. Leaf, tiller, and root production rates are sensitive to light and temperature where nutritional factors are not limiting. Tillering rates also change with stage of regrowth after defoliation. These factors are discussed with reference to their role in determining seasonal trends.