STUDIES ON THE ROOT DEVELOPMENT OF HERBAGE PLANTS

Abstract

The influence of defoliation on the root, stubble and herbage weights of perennial ryegrass during establishment was studied on spaced plants in the greenhouse and field.In the greenhouse trial the rate of root elongation was reduced by a single defoliation. In both the field and greenhouse, cutting reduced the number of roots and tillers per plant but increased the number of roots per tiller. A few weeks after defoliating plants in the field there was a lower root weight on the cut plants than on the uncut. Eventually the influence of a single cut disappeared, but if the cutting was in the laie summer or autumn the plants commenced the winter with a smaller amount of root and stubble, and this appeared to have a deleterious effect on the earliest spring growth.Herbage growth in March and April was positively correlated with both root and stubble weights in the previous November.As the number of cuts during the establishment period (March‐November) was increased from 0–4 the root and stubble weight per plant progressively decreased.The root and stubble weights decreased during the winter.