Study On The Best Condition Of Pyrethrum Seed Germination And Effect Of Aerial Part Aqueous Extract On Seedling Growth In Weeds

Through indoor Petri dishes bioassay method,we explored the effects of variable temperature treatment 、cold storage 、NAA treatment on seed germination of pyrethrum, to help with clearing the best condition of pyrethrum seeds germination. We tested offshoot reproduction ability of pyrethrum growing for two years by field experiment, the aim was to clear the difference of survival rate between spring transplanting and autumn transplanting, and provide technical foundation for scientific planting pyrethrum; At the same time, we tested the effects of aqueous extract of pyrethrum aerial part in six companion weeds, i.e. Euphorbia helioscopia、Veronica didyma、Amaranthus retroflexus、Avena fatua、Descurainia Sophia and Bromus japonicas, to help with realizing the influence of pyrethrum on the seed germination and seedlings growth of common orchard grass, providing reference for scientific utilizing pyrethrum resources to govern weeds and pests. The experimental results indicated that:1. The initial germination rate of pyrethrum seeds by purchasing was 16.17%, However, germination rate of pyrethrum seeds was over 60% by harvest. But there was a common problem that seedlings were hard to survive. Through observation we found that seedling roots were dysplasia after germination, thus seedlings could not survive.2. The optimum temperature range of pyrethrum seed germination was from 15℃to 25℃, 20℃/15℃ was more advantageous for pyrethrum seeds germination than the thermostatic;cold preservation was disadvantage for seeds germination. With the increasing cold storage duration, the seed germination rate and germination energy reduced significantly, seeds germination rate reduced 19.33% after cold storage for 40 days compared with contrast.3. Pyrethrum seeds germination rate increased 14.67% treated with 10-6 g·mL-1 NAA, the content of soluble protein and soluble sugar improved.4. Pyrethrum had a strong capability of offshoot breed. The survival rate, plant height, the number of flowers, tillers, seed thousand grain weight were increased significantly by offshoot breeding in the autumn compared with offshoot breeding in the spring, so we suggested to transplant pyrethrum at autumn as far as possible.5. The degree of inhibition existed significant differences among six weeds in response to different concentrations of aqueous extracts. Overall, lower mass concentrations had a promoting effect on six weeds, Increasing concentrations of aqueous extract significantly inhibited seed germination and growlth of weeds. The highest concentration of aqueous extract at 30mg·mL-1 exhibited the strongest inhibition effect. So we concluded that a certain planting density of pyrethrum could inhibit the growth of companion weeds. Differences in inhibition effects among six studied receptors were observed. Comparably, the sensitive order was ranked as Descurainia sophia>Euphorbia helioscopia>Bromus japonicus>Veronica didyma>Amaranthus retroflexus>Avena fatua.