| Abstrakt: |
Seeds of many plant species contain phytotoxic compounds which inhibit seed germination or seedling growth of other seeds in their immediate vicinity. Seeds of tall fescue (Festuca arundinaceaSchreb.), annual ryegrass (Lolium multiflorumLam.), orchardgrass (Dactylis glomerataL.), Kentucky bluegrass (Poa pratensisL.), alfalfa (Medicago sativaL.), white clover (Trifolium repensL.), sericea lespedeza [Lespedeza cuneata(Dum. de Cours.) G. Don], and crownvetch (Coronilla variaL.) were leached in water for 24 hours and the leachates were used to moisten filter paper in petri dishes for germination. Seeds of each species were germinated in leachate from all eight species. Seeds of the four legumes were also germinated in leachates from nine other ryegrass cultivars and six other orchardgrass cultivars. Germination and seedling growth of a species was not inhibited by leachate from its own seeds. There was no phytotoxicity to any of the grasses by leachate from other grass species. The only phytotoxicity to any of the grasses was a slight inhibition of bluegrass germination and shoot growth by crownvetch seed leachate. Leachate from one commercial lot of annual ryegrass seed almost completely inhibited germination and root growth of each of the legumes. Other cultivars of ryegrass varied from moderate to no phytotoxicity of their leachates. Leachate of ‘Potomac’ orchardgrass seeds caused moderate germination inhibition of white clover and sericea. Six other orchardgrass cultivars showed little variation in phytotoxicity, while uniformly inhibiting root growth of sericea and crownvetch. Inhibition of germination was not a good measure of phytotoxicity since seedling growth was often inhibited when germination was not. |
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