FURTHER STUDIES ON THE RELATIONSHIP BETWEEN SHOOT AND ROOT SYSTEMS OF GRASSES

In young grass plants it is possible to relate the weight of the root to that of the shoot through the allometric formula y = bx ^k . Using this formula it was found that flower formation was associated with an increase in shoot growth relative to that of the root. Within varieties of Lolium , the greater the intensity of heading the more was the growth of the shoot relative to that of the root. Perenniality was associated with a high rate of root growth relative to that of the shoot. A decrease in the light intensity or soil water reduced the growth of the plant as a whole, but light decreased root growth more than that of the shoot while water supply had the opposite effect.