GROWTH AND SURVIVAL OF SEVERELY-SHADED TILLERS IN LOLIUM-PERENNE L

The effect of shading a single tiller to below its compensation point for a period of 5 weeks in vegetative plants of Lolium perenne L. cv. S23, was studied in two different experiments each employing two light regimes, one of which was common to both experiments.In the first experiment tillers in the axils of the first leaf were shaded three weeks from appearance at both 40 and 70 W m-2. None of the shaded tillers died and they continued to produce new leaves and increase in dry weight but at a reduced rate. In the second experiment, tillers with one emerged leaf in any leaf axil position were shaded at 70 W m-2 and in a treatment in which light was reduced to 13 W m-2 after initial growth at 70 W m-2. As in the first experiment all shaded tillers survived at 70 W m-2 but in the 70 → 13 W m-2 transfer regime all shaded tillers died.In the second experiment shaded tillers in both light regimes were supplied with 14C-assimilate by translocation from the remainder of the plant but in the 70 → 13 W m-2 the initial support was withdrawn within 5 weeks of shading.The results are discussed in terms of the physiological relationships between the tillers of the grass plant. © 1979, Annals of Botany Company.