The effect of metfluidide on some physiological aspects of Lolium multiflorum: A report submitted in partial fulfillment of the requirements for the degree of B. Agr.Sci. (Hons)

Abstract

The effect of mefluidide, a plant growth retardant, on Tama ryegrass (Lolium multiflorum) was considerable on all measured growth parameters. Application of mefluidide at 0.3 kgha⁻¹ and 0.6 kgha⁻¹ reduced all dry weight components: roots, crowns, shoots and leaf laminae. This reduction was associated with suppression of tiller and leaf laminae development. Net assimilation rate was suppressed initially but dramatically increased four weeks after mefluidide application. This change was also parallelled by changes in relative growth rate. Tama ryegrass when treated with mefluidide at a rate of 0.61 kgha⁻¹ maintained a higher digestibility than untreated plants. This was attributed to suppression of flowering in the treated plants. Mefluidide caused an increase in the chlorophyll concentration in the leaf laminae when applied as a foliar spray at a rate of 0.6 kgha⁻¹. No significant differences were observable in the stem. When mefluidide was applied to the leaf lamina on the main tiller of Tama ryegrass, 20% was taken up at 24 hours. At 48 hours 32% had been taken up, when the plants were grown at 18°C at a relative humidity of 70%. At 24 hours and 48 hours 16.2% and 13.4% respectively of that absorbed was translocated from the lamina. There was evidence that some of the mefluidide absorbed was metabolized within 24 hours of application.