Based on the results of field trials and soil and plant measurements, the available silicon contents ofpaddy soils, their relations with the SiO_2 content of rice plant, the relationships between rice yield on theone ...Based on the results of field trials and soil and plant measurements, the available silicon contents ofpaddy soils, their relations with the SiO_2 content of rice plant, the relationships between rice yield on theone hand and the SiO_2 content and SiO_2/N ratio of rice plant on the other, the effects of silicon on riceyield and resistance to diseases and pests and the effective conditions and causes for increasing rice yield inSichuan Basin are expounded in the present paper. The study results show that about one half of the paddysoils developed from yellow soil, purple soil, alluvial soil, etc. in Sichuan Province were insufficient in siliconsupply. Critical values for silicon fertilization were 98 mg kg￣(-1) available Si in the paddy soils and < 112.8gkg￣(-1) SiO_2 in the rice plants. A SiO_2 content of rice plant over 121.6g kg￣(-1) and a SiO_2/N ratio maintainedat about 12 were required for gaining a rice yield of 7500 kg ha￣(-1). The yield increase by silicon fertilizationwas due to the improvement of silicon nutrition in rice plants and the balance of SiO_2/N ratio, and the reasonfor enhanced resistance to diseases and pests was concerned with the inhibition of luxury N absorption andthe raising of plant SiO_2/N ratio. Silicon fertilization tended to balance the uptake of N, P and K by riceplant .展开更多
Two kinds of organic-inorganic comp osite luminescent material were pre pared through sol-gel route,by dopi ng o-amino-benzoic acid(ABA)or N-phenylanthranilic acid(N-PA)into SiO 2 xerogels.Fluorescence properties and ...Two kinds of organic-inorganic comp osite luminescent material were pre pared through sol-gel route,by dopi ng o-amino-benzoic acid(ABA)or N-phenylanthranilic acid(N-PA)into SiO 2 xerogels.Fluorescence properties and thermal properties of ABA and N-PA in SiO 2 xerogels were studied.The relation ship between the fluorescence properties and the preparative cond ition was also studied.The results s howed that the ABA was easy to form dim er of non-luminescence among the molec ules.The quenching concentration o f the ABA was obviously increased owi ng to the shield of silica network.The f luorescence intensity of the composite material prepared at the acid con dition was decreased,and a red shift for the fluorescence peak appeared.With th e increasing of the pH value,the flu-orescence peak blue shifted and the i ntensity was increased.However,th e fluorescent intensity of N-PA /SiO 2 was increasing due to the concentration of N-PA was increased.The thermal stability of ABA and N-PA in the composite material was also improved.But,when the temperature continued to incre ase,the collapse of the silica netwo rk made the organic molecules escape fr om the pore of the silica network,the decomposition of escaping molecule s decreased the intensity of emission spectrum.展开更多
文摘Based on the results of field trials and soil and plant measurements, the available silicon contents ofpaddy soils, their relations with the SiO_2 content of rice plant, the relationships between rice yield on theone hand and the SiO_2 content and SiO_2/N ratio of rice plant on the other, the effects of silicon on riceyield and resistance to diseases and pests and the effective conditions and causes for increasing rice yield inSichuan Basin are expounded in the present paper. The study results show that about one half of the paddysoils developed from yellow soil, purple soil, alluvial soil, etc. in Sichuan Province were insufficient in siliconsupply. Critical values for silicon fertilization were 98 mg kg￣(-1) available Si in the paddy soils and < 112.8gkg￣(-1) SiO_2 in the rice plants. A SiO_2 content of rice plant over 121.6g kg￣(-1) and a SiO_2/N ratio maintainedat about 12 were required for gaining a rice yield of 7500 kg ha￣(-1). The yield increase by silicon fertilizationwas due to the improvement of silicon nutrition in rice plants and the balance of SiO_2/N ratio, and the reasonfor enhanced resistance to diseases and pests was concerned with the inhibition of luxury N absorption andthe raising of plant SiO_2/N ratio. Silicon fertilization tended to balance the uptake of N, P and K by riceplant .
文摘Two kinds of organic-inorganic comp osite luminescent material were pre pared through sol-gel route,by dopi ng o-amino-benzoic acid(ABA)or N-phenylanthranilic acid(N-PA)into SiO 2 xerogels.Fluorescence properties and thermal properties of ABA and N-PA in SiO 2 xerogels were studied.The relation ship between the fluorescence properties and the preparative cond ition was also studied.The results s howed that the ABA was easy to form dim er of non-luminescence among the molec ules.The quenching concentration o f the ABA was obviously increased owi ng to the shield of silica network.The f luorescence intensity of the composite material prepared at the acid con dition was decreased,and a red shift for the fluorescence peak appeared.With th e increasing of the pH value,the flu-orescence peak blue shifted and the i ntensity was increased.However,th e fluorescent intensity of N-PA /SiO 2 was increasing due to the concentration of N-PA was increased.The thermal stability of ABA and N-PA in the composite material was also improved.But,when the temperature continued to incre ase,the collapse of the silica netwo rk made the organic molecules escape fr om the pore of the silica network,the decomposition of escaping molecule s decreased the intensity of emission spectrum.
