The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,resp...The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,respectively.The control efficacies of the SL-13 to tomato Rhizoctonia rot were 20.65%and 35.23%in the greenhouse and field,respectively.The growth of the plant-pathogenic fungus Rhizoctonia solani was considerably inhibited in the presence of the strain SL-13 culture supernatant.The main antifungal protein was detected to be chitinase through vitro assay.The chitinase was purified with DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration for further characterization.The optimal pH and temperature for the chitinase activity were 7.0 and 50°C,respectively.It was demonstrated that the enzyme was stable at pH 5-9 and 40-60°C.70%of the enzyme activity was retained when incubated at 121°C and 0.11 MPa for 20 min,and the enzyme was not sensitive to protease K and ultraviolet radiation.Thus it is suitable for effective biological control in relatively unstable environment.展开更多
Irrational irrigation practices in the Arys Turkestan Canal command area in the southern part of Kazakhstan have led to the formation of soils with poor physical and chemical properties. To study whether irrigation an...Irrational irrigation practices in the Arys Turkestan Canal command area in the southern part of Kazakhstan have led to the formation of soils with poor physical and chemical properties. To study whether irrigation and leaching practices and/or groundwater rise have contributed to the accumulation of Mg2+ on the cation exchange complex of these soils, historical changes in soil and groundwater quality were used as source data and the Visual MINTEQ model was applied to analyze the chemical composition of water and soils in the study area. The imposed irrigation regime and the leaching of light sierosem soils led to the dissolution and subsequent leaching of inherent gypsum and organic matter from the soil profile. Further, the domination of bicarbonate in the irrigation water promoted weathering of the carbonate minerals present as calcite. The higher concentrations of Mg2+ in comparison to Ca2+ in the irrigation water resulted in the replacement of Na+ by Mg2+ on the cation exchange complex. In the lower part of the command area, shallow groundwater has contributed to the accumulation of Na+ and to a large extent of Mg2+ on the cation exchange sites.展开更多
In the northeast region of New Brunswick, the majority of peatlands are mainly used for horticultural purposes. Abandoned peatlands after peat extraction could represent one of the most important ecological resources ...In the northeast region of New Brunswick, the majority of peatlands are mainly used for horticultural purposes. Abandoned peatlands after peat extraction could represent one of the most important ecological resources through their remaining substrates： serving as agronomic, ecological or environmental value-added support to local development; and giving a second economic life to peatlands. To evaluate this innovative peat soil management, a study was conducted on three residual peatlands from the Acadian Peninsula. Their status was described through a physic-chemical characterization. The results suggest that the peat thickness and the mineral horizon characteristics are good indicators to identify these post-harvest peat soils. The studied sites were characterized by a flat topography, poor and unequal drainage inducing a variation of the water table level. The peat thickness ranged from 18 cm to 40 cm, while the thickness of the mineral horizon--mostly sandy--ranged between 20 cm and 30 cm. The chemical properties revealed an electrical conductivity above 50 μS·cm^-1, an acid pH, and a variable cation exchange capacity （1.3 cmolc·kg^-1 to 11.4 cmolc·kg^-1）. This preliminary study gives basic knowledge on Acadian Peninsula abandoned peatlands soils and gives information about the conditions of their agro-economic, ecological and/or environmental management.展开更多
基金Supported by the National Natural Science Foundation of China（20776017） the Xinjiang Uygur Autonomous Region High-tech Research and Development Project（20081108）+1 种基金 the Fok Ying Tung Education Foundation（101071） the Xinjiang Bingtuan Key Science and Technology Industry Project（2008GG24）
文摘The seed germination and tomato seedling tests showed that Bacillus subtilis SL-13 could promote the sprouting and seedling growth of tomato.The fresh and dry weight of tomato seedlings increased 42.86%and 18.75%,respectively.The control efficacies of the SL-13 to tomato Rhizoctonia rot were 20.65%and 35.23%in the greenhouse and field,respectively.The growth of the plant-pathogenic fungus Rhizoctonia solani was considerably inhibited in the presence of the strain SL-13 culture supernatant.The main antifungal protein was detected to be chitinase through vitro assay.The chitinase was purified with DEAE-Sepharose fast flow ion exchange column chromatography and Sephadex G-75 gel filtration for further characterization.The optimal pH and temperature for the chitinase activity were 7.0 and 50°C,respectively.It was demonstrated that the enzyme was stable at pH 5-9 and 40-60°C.70%of the enzyme activity was retained when incubated at 121°C and 0.11 MPa for 20 min,and the enzyme was not sensitive to protease K and ultraviolet radiation.Thus it is suitable for effective biological control in relatively unstable environment.
基金Project supported by the Asian Development Bank (No.RETA 6208).
文摘Irrational irrigation practices in the Arys Turkestan Canal command area in the southern part of Kazakhstan have led to the formation of soils with poor physical and chemical properties. To study whether irrigation and leaching practices and/or groundwater rise have contributed to the accumulation of Mg2+ on the cation exchange complex of these soils, historical changes in soil and groundwater quality were used as source data and the Visual MINTEQ model was applied to analyze the chemical composition of water and soils in the study area. The imposed irrigation regime and the leaching of light sierosem soils led to the dissolution and subsequent leaching of inherent gypsum and organic matter from the soil profile. Further, the domination of bicarbonate in the irrigation water promoted weathering of the carbonate minerals present as calcite. The higher concentrations of Mg2+ in comparison to Ca2+ in the irrigation water resulted in the replacement of Na+ by Mg2+ on the cation exchange complex. In the lower part of the command area, shallow groundwater has contributed to the accumulation of Na+ and to a large extent of Mg2+ on the cation exchange sites.
文摘In the northeast region of New Brunswick, the majority of peatlands are mainly used for horticultural purposes. Abandoned peatlands after peat extraction could represent one of the most important ecological resources through their remaining substrates： serving as agronomic, ecological or environmental value-added support to local development; and giving a second economic life to peatlands. To evaluate this innovative peat soil management, a study was conducted on three residual peatlands from the Acadian Peninsula. Their status was described through a physic-chemical characterization. The results suggest that the peat thickness and the mineral horizon characteristics are good indicators to identify these post-harvest peat soils. The studied sites were characterized by a flat topography, poor and unequal drainage inducing a variation of the water table level. The peat thickness ranged from 18 cm to 40 cm, while the thickness of the mineral horizon--mostly sandy--ranged between 20 cm and 30 cm. The chemical properties revealed an electrical conductivity above 50 μS·cm^-1, an acid pH, and a variable cation exchange capacity （1.3 cmolc·kg^-1 to 11.4 cmolc·kg^-1）. This preliminary study gives basic knowledge on Acadian Peninsula abandoned peatlands soils and gives information about the conditions of their agro-economic, ecological and/or environmental management.
