| Poplar and willow are very important backbone trees for city greening of China.They are also the earliest leafing out and the latest defoliating broad-leaved trees in the north of China,which have a lot of other merits,such as big and high tree body,large shading area and better shading effect.Thus,they have played an irreplaceable role in the city ecological environment improving and formed the city landscape with distinct four-season themes.Although the ecological and social benefits of poplar and willow to the city greening are significant but in the period of blossoming and fruits bearing,the male ones will release pollen,and the female ones will release fluff.The pollen or fluff of poplar and willow not only polluted the city ecological environment,but also endangered the public and traffic safety,and the health of city resident.The problem of pollen and fluff of poplar and willow had greatly restricted the continually and further use of poplar and willow in city greening.So,there have a critical requireme to resolve this problem.This project intend to develop a kind of chemical such merits as low cost price,having no or very low environmental pollution,having extremely better controlling effect,and so on,to refrain the pelleting and fluffing of poplar and willow.And on the basis of above research,the application and the safety appraising of this chemical have been researched.The main results are following:1.No.1 of blossom bud restrainer(BBR Ⅰ)can effectively restrain the floral bud differentiation of male and female plants of Populus tomentosa and Salix matsudana f.pendula.So,it can effectively control the pollening and fluffing of those plants.2.It has been determined that the injecting times,the injecting concentrations,the injecting doses of BBR Ⅰ,and the sizes of poplar and willow all have influence on the controlling effects,of which the injecting times and injecting doses are main factors.The multivariant regression equation of the injecting times,the injecting doses of BBR Ⅰ,and the sizes of Populustomentosa and Salix matsudana f.pendula with the fluff controlling effects have been established respectively.3.There have no damage was observed after the BBR Ⅰ were injected at concentration of 100 times of controlling dose into the P.tomentosa and S.matsudana f.pendula.And the injecting of BBRⅠ can improve the growth vigour of P.tomentosa and S.matsudana f.pendula,because of that the nutrition originally for reproductive growth has been used for vegetative growth after the injection of BBR Ⅰ.Thus,there have no drug misadventure of BBR Ⅰ on P.tomentosaand S.matsudana f.pendula.4.There have no damage on Rosa hybrid,Ligustrum vicaryi,Euonymus japonicus,Buxus sinica,Berberis thunbesgii var.atropurpurea,Hemerocallis hybridus,Hosta plantagine,Poa pratensis,Kerria japonica,Forsythia suspense and Prunus triloba after the BBR Ⅰ was sprayed at the concentration of 500 ppm.It could not reduce the floral bud differentiation ratio of R.hybrida,H.hybridus and H.plantaginea after the BBR Ⅰ was sprayed at the concentration of 500 ppm.But it could reduce the floral bud differentiation ratio of K.japonica,F.suspense and P.triloba.5.It has determined that the injecting method further suit for the fluff controlling of poplar and willow through contrasting the merits and demerits of injecting method and spraying method... |
