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Divalent phosphate ion activities can be measured in dilute aqueous solutions in the physiological pH range (7.0 to 7.5) with a liquid ionexchange membrane electrode system; the organic ion exchanger consists of an amine chloride membrane. Reference solutions may be either aqueous chloride or bicarbonate solutions. An essentially Nernstian slope is obtained. 相似文献
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产多糖溶磷细菌对难溶性Ca-P的活化特性 总被引：3，自引：0，他引：3
以肠杆菌EnHy-401、节杆菌ArHy-505、固氮菌AzHy-510和巨大芽孢杆菌P17为材料,比较了4种溶磷细菌在摇瓶培养条件下对不同难溶性Ca-P中的磷活化能力.结果表明,4种溶磷细菌均能促使难溶性Ca-P中的磷活化, 但3种产多糖的溶磷细菌(EnHy-401、ArHy-505、AzHy-510)对难溶性Ca-P的活化能力普遍强于不产多糖的溶磷细菌(P17),肠杆菌EnHy-401对Ca3-P、Ca8-P和Ca10-P中的磷活化率分别达61.53%、63.40%和4.32%.在产多糖的溶磷细菌中,有机酸和多糖均高的菌株活化磷的能力最高,3种产多糖的溶磷细菌活化难溶磷酸钙能力的大小顺序依次为肠杆菌EnHy-401、节杆菌ArHy-505、固氮菌AzHy-510.结果还表明,产多糖的溶磷细菌对难溶磷的活化作用是由分泌有机酸和多糖的协同作用实现的,多糖对磷的吸持推动了磷的溶解平衡向溶解方向移动,且该协同作用受胞外多糖持磷能力和环境中C/N的影响,单位体积发酵液中多糖持磷量与菌株的磷活化能力呈正相关.在本试验条件下,C/N值高时,多糖产量高,有机酸分泌多,活化磷的能力就强.同一菌株只有在最适于产有机酸和产多糖的C/N值下,才能表现出最佳的溶磷效果. 相似文献
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Phospholipid-calcium phosphate complex: enhanced calcium migration in the presence of phosphate 总被引：1，自引：0，他引：1
In the presence of acidic phospholipids, inorganic phosphate greatly enhances the net migration of calcium ions from the aqueous phase to the organic phase, an effect that does not occur at less than the physiological pH. The calcium complex in the organic phase is shown by electron microscopy to consist of spherules, composed of stoichiometric amount of calcium, inorganic phosphate, and phospholipid. The demonstration of complex formation between calcium phosphate and acidic phospholipids adds Support to the concept that phospholipids are involved in biological mineralization. 相似文献
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为探明腐植酸与磷肥施用方式对土壤磷素移动性和淋失量的影响,通过室内土柱淋溶试验,分别设计了不施肥（CK）、基施腐植酸钾追施/不追施磷肥（HA-P、HA）、基施磷肥追施/不追施腐植酸钾（P-HA、P）和磷肥腐植酸钾共同基施（P+HA）共6个处理,来探讨将腐植酸水溶性肥料中的主要原料腐植酸钾与磷肥按照不同施用方式施入土壤后对土壤磷素剖面迁移能力和淋出的影响。结果表明：在相同的灌溉条件下,HA-P处理显著增加了土壤磷素的淋出,分别比P-HA、P和P+HA 3个处理的磷素淋出总量高244.08%、78.51%和35.34%,而P-HA则显著降低了土壤磷素的淋出量;P+HA和P-HA处理土壤剖面的速效磷和全磷含量均随土层深度的增加而显著增加,与P处理结果相似,而HA-P处理剖面各层土壤的速效磷和全磷含量差异较小;HA处理会使土壤磷素淋出略有增加。研究表明,腐植酸钾与磷肥等量输入时,以腐植酸钾为基肥、磷溶液进行追肥的施用方式对土壤磷素移动的促进作用最大,有较高的淋失风险,而基施磷肥、追施腐植酸钾则可以显著控制土壤剖面磷素移动,降低土壤磷素的淋出量。 相似文献
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采用选择性培养基对柳桉、邓恩桉和尾巨桉3种桉树林地根际土壤解磷细菌进行分离和筛选,并对其解磷能力进行测定.结果表明:(1)3种林分根际土壤中均存在大量的解磷细菌,其中的解有机磷细菌数量为(2.23~4.17)×104cfu·g-1,溶无机磷细菌数量为(2.05~4.00)×104cfu·g-1,解有机磷细菌数量多于溶无机磷细菌数量.不同林分根际土壤解磷细菌数量分布有差异,其数量大小为:柳桉尾巨桉邓恩桉.(2)筛选到12株溶无机磷细菌和14株解有机磷细菌,且不同解磷细菌的解磷能力存在显著差异(P0.05).12株溶无机磷细菌在无机磷培养液中的有效磷含量为55.854~367.169μg·m L-1,最大为P7菌株;14株解有机磷细菌在有机磷培养液中的有效磷含量为11.374~30.330μg·m L-1,最大为YP菌株.溶无机磷细菌溶解的无机磷含量与蒙金娜无机磷培养基的p H之间存在极显著负相关性(P0.01),解有机磷细菌分解的有机磷含量与卵黄培养基的p H之间无显著相关性(P0.05).综上所述,26株解磷细菌中,P7菌株溶解无机磷的能力最强,YP8菌株分解有机磷的能力最强,这两个菌株可作为下一步研制桉树微生物肥料的重点菌种. 相似文献
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Nelson BW 《Science (New York, N.Y.)》1967,158(3803):917-920
The widespread occurrence of sedimentary phosphate in argillaceous sediments provides the basis for a new method of paleosalinity estimation. Sedimentary phosphate contains iron- and calcium-phosphate fractions, the relative proportions of which are sensitive to salinity of the water at sites of deposition. The sedimentary phosphate method provides direct estimates of paleosalinity throughout the freshwater to marine range. 相似文献
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以灭菌和未灭菌的耕层下犁底层瘠薄土为基质,以Gv,Gm,Gs,Gi等4种丛枝菌根菌(AM)为材料,研究AM菌对玉米的作用。结果表明,不同的AM菌提高土壤有效磷含量和促进玉米对磷的吸收作用不同。在土壤灭菌条件下,Gs和Gi 2种AM菌提高土壤有效磷含量和玉米地上部植株中磷含量的作用最显著。土壤没有消毒处理条件下,仅Gm菌处理的土壤有效磷和植株磷含量均显著高于对照;而Gi处理的土壤有效磷含量的增加虽未达到显著水平,但植株磷含量却极显著高于对照。在土壤灭菌条件下,Gv和Gm侵染玉米根系的进展快于Gs和Gi;而在土壤没有消毒处理条件下,Gs侵染玉米根系的进展最快,其次为Gv和Gm,Gi侵染玉米根系速度最慢。 相似文献
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A theory for the rapid specific reaction of certain phosphorous-containing esters with many proteolytic enzymes based on the ability of phosphorous to form one additional bond relative to carbon is presented. A stable tetrahedral phosphate ester is compared with a labile tetrahedral orthocarbonyl ester and a relatively stable pentagonal enzyme-phosphate ester complex is compared with a pentagonal enzyme-carbonyl substrate complex. The latter complex is assumed to be the transition state in the enzyme-catalyzed reaction. If the theory is correct, it opens up the possibility of studying intermediates and transition states from the known structures of chemical inhibitors. 相似文献
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对解磷微生物肥料的研究概况进行了综述,内容包括解磷微生物解磷能力及解磷机制的研究方法和进展、解磷微生物制剂和菌肥的应用和发展等. 相似文献
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Previous attempts to phosphorylate nucleosides by heating with inorganic phosphate succeeeded only when acid phosphates such as Ca(HPO(4))(2) were used. The addition of urea and ammonium chloride to the reaction mixture permits phosphorylation in high yield with neutral or basic phosphates at temperatures in the range of 65 degrees to 100 degrees C. Since the abundant mineral, hydroxylapatite, is a satisfactory substrate for this reaction, we believe that this procedure plausible model for prebiotic phosphorylation. 相似文献
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《农业科学学报》2019,18(9):2153-2161
Phosphorus(P) is a limiting nutrient element for crop. To obtain maximum crop yield, P fertilizer is often over-applied, which leads to accelerating exhaustion of phosphate resources and serious environmental problems. Reducing the application of P fertilizer and enhancing the P utilization efficiency of crops are significant for the sustainable development of agriculture. Cadmium(Cd) contamination in rice is another serious agricultural issue. However, whether reducing the application of P fertilizer and enhancing the P utilization efficiency of crops will increase the risk of Cd accumulation in crops remains obscure. In this study, we are aiming to elucidate the relationship between Cd and P in rice from physiological and genetic perspectives. For this purpose, the wild type(WT) rice plants and phosphate(Pi)-starvation signaling repressed mutant phr2 were used to analyze the relationship between Cd and P. Here, we found that Cd stress could promote P accumulation and induce Pi-starvation signaling in WT and phr2 shoots under Pi-sufficient condition in a PHOSPHATE STARVATION RESPONSE 2(PHR2) independent manner. Besides, the expression level of Cd transporter of OsNramp5 and the uptake speed of Cd~(2+) were not obviously changed under Pi-sufficient and Pi-deficient conditions. Furthermore, our Cd determination results showed that the Cd concentrations in WT and phr2 were not obviously changed under Pi-sufficient and Pi-deficient conditions. These results indicate that the external P availability and internal Pi-starvation signaling cannot obviously affect the accumulation of Cd in rice seedling. 相似文献
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利用~(32)P示踪技术研究土壤磷素活性剂对大豆吸收土壤和肥料磷素量的影响 总被引：1，自引：1，他引：1
应用 3 2 P示踪技术研究了土壤磷素活化剂在磷肥肥效方面的影响。结果表明 ,施用土壤磷素活化剂可增加土壤磷素和肥料磷素的供应强度 ,促进大豆对土壤磷素和磷肥磷素的吸收。 相似文献
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磷酸运转器作为调节植物光合产物运转的关键蛋白之一，一直是光合作用研究的重要内容，且多集中在对其运转的生理生化功能的研究。总结了不同类型植物的质体中磷酸运转器的基因结构及其特性，同时也比较了它们的功能。磷酸运转器由核DNA编码，分子量约为36000D。不同的磷酸运转器起源于同一祖先，后相续进化而形成。同一植物不同的基因编码不同的磷酸运转器。C3植物的磷酸运转器调节磷酸（Pi）、磷酸二羟丙酮（DHAP）和3-磷酸甘油酸（3PGA）之间的反向交换运输，而2-磷酸甘油酸（2PGA）、磷酸烯醇式丙酮酸（PEP）、葡萄糖-6-磷酸（G6P）很少或根本不被运输。C4和CAM植物叶绿体中的磷酸运转器除了上面提到的代谢物以外还运输PEP，植物根质体中磷酸运转器也运输G6P。植物同一片叶子不同的细胞具有不同的叶绿体磷酸运转器。表1参36 相似文献
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李翠萍 《郑州牧业工程高等专科学校学报》2010,30(3)
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钙、磷缺乏是由于饲料中钙、磷不足,或二者比例不当,或维生素D缺乏从而引起机体钙、磷缺乏,使小猪发生佝偻病,成年猪发生骨软症的代谢病.临床上以消化紊乱、异食癖、骨骼弯曲为主要特征.现代规模化猪场,由于饲料营养全面,猪群已很少发生本病. 相似文献