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罗文富 《云南农业大学学报(自然科学版)》1997,12(3):214-218
能抑制植物病害的土壤称为抑病土.抑病土在世界上分布广泛,已报道了多种植物土传病害可被土壤抑制.在烟草黑根病抑病机制的研究方面也有许多报道,本文根据这些作者及自己的研究资料加以综述. 相似文献
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Pig slurry in quantities of 200, 400, 500, 600, 800, and 1000 m3 ha-1 year-1 was added to two calcareous soils, which differed in concentration and type of clay minerals. The soils were cultivated with two successive crops of pepper and tomatoes grown in containers. A control was given no slurry. The soils were analysed after harvesting for exchangeable K+. Differences in exchangeable K+ were studied in relation to the concentration and type of clay minerals. The soil with the higher clay content and of the illite type retained K in the exchangeable form to a much greater extent than the soil with the low clay content. In the soil with the lower clay content, of the interstratified illitic — montmorillonite type, very little K was incorporated into the exchange complex. The exchange capacity being low, the amount of K added had little effect on the level of exchangeable K+. 相似文献
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Mohamed H. Abd-Alla 《Biology and Fertility of Soils》1994,18(3):216-218
Rhizobium leguminosarum biovarviceae strain TAL 1236 growing on different organic P compounds as sources of phosphate exhibited phosphatase activities. The strain was able to produce both acid and alkaline phosphatase. However, its ability to produce alkaline phosphatase was much higher. When cellular phosphate fell to 0.115% of cell protein, cellular and extracellular phosphatase activities were enhanced. Mg2+, Co2+, and Ca2+ stimulated the activity of alkaline phosphatase more than acid phosphatase. However, Mn2+ and Fe2+ activated acid phosphatase rather than alkaline phosphatase. It may be concluded thatR. leguminosarum contributes significantly to the release of P from organic compounds through the action of phosphatase which can be activated by a range of cations. 相似文献
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对英国苏格兰西部地区欧洲栎林分的调查表明,由于环境的酸化,在表层土壤中(0—5cm)交换性阳离子含量与1981年相比明显下降,离子饱和度在9.8%-50.1%之间,平均为20.2%。小根的生长与3年前相比有所增加,但死根检出率也相应上升,这反映出养份的淋失,已对栎树生长造成一定影响。 相似文献
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为研究内毒素(ET)致大鼠肝细胞凋亡变化、对肝脏Caspase-3蛋白表达的影响及阳离子A(CA)的保护效应.将试验动物随机分为3组:对照组(Ⅰ组)、ET组(Ⅱ组)和CA保护组(Ⅲ组).3组动物经相应处理后分别在3、4、8、12 h采集肝脏检测肝细胞凋亡情况和Caspase-3蛋白的表达情况.结果表明,肝细胞凋亡与Caspase-3蛋白的表达成正相关的关系.ET可上调Caspase-3蛋白在肝脏的表达,诱导肝细胞凋亡,最终导致肝脏受损;而CA则能明显下调Caspase-3在肝脏的表达,抑制肝细胞凋亡,对由ET诱导的肝损伤具有显著的保护效应. 相似文献
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D.L. Barnes M. Swart M.F. Smith G.H. Wiltshire 《African Journal of Range and Forage Science》2013,30(3):92-98
Forty systematically‐placed observation points were established in a 1.5‐ha area of floristically unifoim veld in which productivity varied spatially. At each point grass yields were determined by harvesting quadrats at eight‐week intervals during the growing season, and the volumetric water content of the soil was measured weekly. In addition, root mass and root‐N content, and soil variables involving C and N contents, extractable P, K, Ca and Mg, cation exchange capacity and base saturation, pH, clay content and soil depth, were determined. The data were examined using linear correlations between variables, principal components analysis and multiple regression. The major factors associated with variations in yield were, in order of importance, soil water content, the N supply (as expressed by root‐N content or root‐N mass) and the cation supply (as expressed by the topsoil variables, extractable Ca or cation exchange capacity or percentage base saturation). There was a relatively weak positive association between yields and the H+ concentration in the subsoil, and a weak negative association between yields and the clay content of the topsoil. A multiple regression function involving all five factors accounted for 77.3% of the variation in dry matter yield. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(7):665-676
Abstract Magnesium (Mg) deficiency In corn (Zea mays L.) is a major problem in many parts of the world because of widespread soil Mg deficiency. One approach to growing corn on infertile soils is to develop hybrids by breeding for better mineral element efficiency. This study was conducted on two soils low and medium in available Mg with corn planted on different dates to determine if hybrids were consistent for differences in mineral element efficiency. Hybrids did not differ in yield at each location but differed between soils. Yield decreased from late plantings. Ear leaf concentrations were greatly affected by soils and planting dates for most elements. Hybrids differed In efficiency of all elements but P, Zn, and Mn efficiency was not consistent between soils. Iron, K, Ca, and Mg concentrations in the ear leaf were genetically consistent in relative efficiencies among hybrids on both soils. Concentrations of K, Ca, and Mg In leaf tissue appeared to be positively related to soil test. Cation sums and ratios were different among hybrids and were rather consistent between soils. Data indicate that hybrids do differ in Mg efficiency as well as other elements and cation balance. The use of genetics to manipulate hybrids for efficiency on low Mg Infertile soils should be feasible. 相似文献