沙棘根瘤共生固氮的研究

研究了生长季节、坡向、植株年龄、植株性别诸因子对沙棘根瘤共生固氮作用的影响,结果证明:季节变化是造成固氮酶活性变化的主要因子;阴坡沙棘根瘤的共生固氮作用与株龄密切相关,而阳坡则不明显;坡向、树龄和沙棘性别均未构成对沙棘根瘤固氮酶活性的显著差异.     

Short‐term releases of CO2 from newly mixed biochar and calcareous soil

The work aimed to quantify native organic C mobilized in one calcareous soil in the 21 days after addition of biochar at a range of large to very large applications. The experiment was carried out in unplanted microcosms, and CO₂ flux was used as a measure of net mineralization. A rapid methodological approach, which does not require ¹³C as a tracer, was used to assess any priming effects induced by the biochar. The amount of CO₂‐C mobilized was small relative to the amount of biochar C and proportional to the amount of the biochar added. The additional CO₂‐C was similar to the content of the water‐soluble organic carbon in the biochar added with each application. No interaction with native soil C, that is priming effect, was observed.     

Root growth enhancement by rhizospheric aluminum treatment in Quercus serrata Thunb. seedlings

This article discusses the effect of aluminum on root growth of Querucus serrata Thunb. In a 9-week hydroponics experiment, the effects of various concentrations (0 to 5.0 mM) of Al on root growth were examined. Results revealed that root biomass increases with the increase in Al concentration up to 2.5 mM, and then it tended to decrease. In the next experiment, the effects of H⁺ and Al³⁺ on roots were compared in a 4-week hydroponics experiment using three treatment solutions: control (pH 6.0), −Al (without Al, pH 3.5), and +Al (with 2.5 mM Al, pH 3.5). No clear difference in the biomass and root length between the control and −Al treated roots was observed, and root and shoot biomass were increased by Al treatment. These results confirmed that the H⁺ concentration level, at a pH of 3.5, is not toxic for Q. serrata and the Al-induced increase in root biomass is not caused by the amelioration of H⁺ toxicity by Al. In the third experiment, roots were exposed to an Al solution (pH 3.6) intermittently. This treatment clarified that Al stimulated rooting and root elongation. In the fourth experiment, the effect of 1 mM Al on root growth during a 15-month period in a sand culture were examined. This experiment confirmed that Al stimulated good growth and development of root systems at appropriate concentrations. Therefore, it is considered that Al-induced root growth enhancement occurs as a long-term and short-term phenomenon.     

基体改良效应石墨炉原子吸收法直接测定植物样品中微量钼

本文研究利用460μg/mlNa_2CO _3—1000μg/mlCa_(2+)复合溶液作石墨炉原子吸收法(GFAAS)直接测定植物样品中微量钼的基体改良剂,详细讨论了该改良剂的作用、特性、钼原子化条件和基体干扰情况。使用本试验推荐的基体改良剂,在一定的浓度范围内能彻底消除钼的记忆效应,大大提高测定灵敏度,钼的原子吸收信号增加104.6％,特征性浓度为0.5ng/mlMo,相对偏差(RSD)为2.4％。     

复合菌剂对草莓黄萎病的田间防治效果

由轮枝孢属真菌Verticillium spp.引起的草莓黄萎病在草莓各产区均有发生,危害严重。在江苏镇江和扬州两地的大田试验表明复合菌剂能有效防治草莓黄萎病,平均防效达到76.8%。该菌剂对草莓有较好的促生作用,150d时,无病田平均增产25.8%,病田增产133.6%。     

石榴皮提取物的酶抑制作用研究

[目的]研究石榴皮提取物对α-淀粉酶和α-葡萄糖苷酶的抑制作用。[方法]以液固比、提取时间、微波功率3个因素,石榴皮多酚为响应值进行Box-Behnken设计,对石榴皮进行提取。以淀粉和PNPG为底物,构建符合人体糖尿病病理的生理特征、更加具有临床意义的高通量体外筛选模型。[结果]结果表明,石榴皮提取物对α-淀粉酶的抑制作用随浓度的增加而增加,60 mg/ml时达39.55%;石榴皮提取物对α-葡萄糖苷酶的抑制作用,浓度在1~10μg/ml时,其抑制率与浓度呈线性关系;当浓度≥10μg/ml时,其增大趋势趋于平缓。提取物浓度在10μg/ml时,其抑制率达90%。[结论]石榴皮提取物对α-淀粉酶和α-葡萄糖苷酶都有不同程度的抑制作用,是潜在的降糖功能因子。     

电解质阴离子和pH对可变电荷土壤硫酸盐吸附的影响

The effects of three electrolyte anions, ionic strength and pH on the adsorption of sulfate by two variable charge soils, with different surface charge properties were studied. Under the conditions of the same pH and ionic strength the effect of electrolyte anions on the adsorption of sulfate was in the order of Cl^- > NO₃^- > ClO₄^-, indicating the difference of the nature among these three anions. For Ferralsol in the same concentration of chloride and perchloride solutions, the two sulfate adsorption-pH curves could intersect at certain pH value. When pH was higher than the intersecting point, more sulfate was adsorbed in the perchloride solution, while when it was lower than the intersecting point, more sulfate was adsorbed in the chloride solution. In different concentrations of electrolyte solution, the curves of the amount of oxy-acid anion adsorbed, which changed with pH, could intersect at a certain pH, which is termed point of zero salt effect (PZSE) on adsorption. The nature of electrolyte anions influenced obviously the appearance of PZSE for sulfate adsorption. For ferralsol the curves of adsorption converged to about pH 7 in NaCl solution seemed to intersect in NaNO₃ solution and to have a typical PZSE for sulfate adsorption in NaClO₄ solution. For Acrisol the three curves of adsorption were nearly parallel in NaCl and NaNO₃ solutions and converged to pH 6.5 in NaClO₄ solution.     

水稻对红壤中N、P的吸收利用

试验结果表明,当施氮量一定的情况下,增施磷、钾肥,氮肥利用率和水稻的产量都有显著的增加。谷粒产量和氮肥利用率为29.78g/盆和44.37％,分别比对照(单施氮肥)提高22.75％和9.62％。合理施用氮、钾肥,磷肥的利用率也有显著增加(为29.10％),比单施磷肥利用率提高6.88％。     

极低温辐照大麦种子及热冲击后处理诱变效应的研究

本试验研究了极低温(-196℃)条件下γ射线辐照大麦干种子和极低温辐照结合热冲击后处理的诱变效应。结果表明:1.与常温条件下辐照相比,极低温条件下辐照及结合热击冲后处理均能显著减轻大麦M_1代的生理损伤和染色体畸变率,其半致死照射量分别提高13kR和30kR;2.M_2代的突变率随照射量升高而增加(r=0.9922~(··)),而与不同温度条件没有关系;3.在极低温条件下用50kR辐照及用60—65kR辐照结合热冲击后处理,与常温条件下用35—40kR辐照相比,没有加重M_1代的辐射损伤,而M_2代的突变率则显著增加,其诱变效率分别平均提高30％和48％。     

基于SEM的农户施肥行为及其影响因素实证研究

农户是农业生产中生产要素的主要投资者,是施用化肥的主体,因此关注农户的施肥行为及其影响因素,对保护农业生态环境有很重要的意义。基于河南省驻马店地区的281份有效问卷,采用结构方程模型(SEM)探讨影响农户施肥行为的主要因素。结果表明:过量施用化肥的认识、有机肥施用效果认知和提高施肥技能对农家肥施用行为的影响是显著正向的,标准化路径系数分别为0.194 6、0.634、0.486,对商品有机肥施用行为的影响是显著正向的,标准化路径系数分别为0.102 8、0.335、0.568,而对化肥合理施用行为的影响不显著,标准化路径系数分别为0.142 6、-0.024、0.194,了解化肥信息对化肥合理施用行为的影响是不显著的,标准化路径系数为0.087。在此基础上提出建议:加强农户对化肥过量危害的负面认识,农户对有机肥施用效果的认知程度,完善农家肥补贴措施和重视施肥技术培训工作。