Effects of flowering on the root system and summer survival of ryegrass

Abstract

Summary Tillers from a clone of short-rotation ryegrass, each with two or three roots, were planted out on three dates, 23 October, 15 November, and 14 December 1956. In half the plants all new roots were cut off as they appeared. The number of flower heads formed decreased with later dates of planting. In the plants whose root systems were restricted to two or three roots, this decrease was associated with an increase in the period between dying back of the flower heads and death of the plant: in the earlier- and more profusely-flowering plants the vegetative tillers died when the flowering tillers died back in the autumn, while in the later-and less profusely-flowering plants, the non-flowering tillers remained alive into the winter or spring. By the time the treated plants had died, the roots had lost most of the cortex and root hairs from all except the finest branches. In the intact plants, sloughing of the cortex did not occur at flowering, but was evident subsequently in some of the older roots. It...