Physico‐chemical characterization of humic‐metal‐phosphate complexes and their potential application to the manufacture of new types of phosphate‐based fertilizers

The aim of this review is to describe the main physicochemical characteristics of diverse types of humic‐metal‐phosphate acid complexes. The effects of these complexes on phosphorus (P) fixation in soils with different pH values and physicochemical features and on plant phosphorus uptake are also discussed. Humic‐metal‐phosphate complexes have apparent stability constants in the same range as those of metal‐humic complexes, in solutions with diverse pH and ionic‐strength values. Likewise, the molecular‐size distribution of humic‐metal‐phosphate complexes as a function of pH is similar to that of potassium or sodium humates and metal‐humic complexes. Humic‐metal‐phosphate complexes are able to decrease phosphate fixation in soils and increase plant growth and phosphate uptake. Phosphorus fertilizers containing humic‐metal‐phosphate complexes proved to be efficient to improve plant growth and P uptake with respect to conventional fertilizers such as single superphosphate. The values of parameters related to plant phosphorus‐utilization efficiency (PUt E) suggest that the regulation of root acquisition of phosphate from these complexes could involve the interregulation of a system for the optimization of metabolic P utilization in the shoot and another system involving stress responses of roots under phosphorus deficiency.     

<Emphasis Type="Italic">Pinus halepensis</Emphasis> somatic embryogenesis is affected by the physical and chemical conditions at the initial stages of the process

Pinus halepensis has been described as a drought-tolerant species with high plasticity to growth in different environments. Its eco-physiological characteristics could facilitate the use of this species in large afforestations in the future scenery of climate change. Somatic embryogenesis is a biotechnological tool with potential for large-scale clonal propagation. In order to establish an improved regeneration protocol for Pinus halepensis, the effects of different temperatures (18, 23, and 28 °C) and water availability conditions (2, 3, and 4 g L^?1 Gelrite^®), during initiation of embryonal masses on the rate of initiation, proliferation, maturation, and the number of embryos developed, were evaluated. It was found that environmental conditions during the initiation stage of Pinus halepensis somatic embryogenesis influence the success of initiation and proliferation. In contrast, there was no effect of these conditions on the maturation rates and the number of somatic embryos. Somatic embryos were obtained in all treatments tested, indicating that plants can be produced from extreme conditions of induction, such as high temperatures (28 °C) and low water availability conditions (4 g L^?1).     

抗福美双假单胞菌株的NTG化学诱变及分子探针鉴定

利用微生物的抗药性筛选抗福美双的假单胞菌株Ｔ４６，然后通过亚硝基胍（ＮＴＧ）化学诱变获得了对福美双敏感的三株突变株Ｔ４６Ｎ１０、Ｔ４６Ｎ７和Ｔ４６Ｎ１７。利用这三个突变株作受体，通过基因克隆的方法筛选到了可使三个突变株恢复抗性的克隆，抗性基因分别被定位在７ｋｂ、２．５ｋｂ和２０ｋｂ的ＥｃｏＲⅠ片段上。将这三个克隆分别用（３２）Ｐ标记后制成分子探针，然后分别与三个突变菌株的总ＤＮＡ进行ＤＮＡ－ＤＮＡ分子杂交，结果表明，各突变株均存在与菌株Ｔ４６的抗福美双基因克隆的高度同源性，经结合形态、生理生化等分析后证实这三株突变株均源自于出发菌株Ｔ４６。     

辽宁省凌源市野生苦参资源的现状及开发利用

近年来,随着中草药价格的提升,农村闲散人员采挖野生苦参的现象较多,致使荒山及林地造成严重水土流失,也对野生苦参资源造成毁灭性破坏,保护野生苦参资源,发展人工种植,对提高当地人均收入,切实可行。     

真空平板玻璃传热理论分析及试验

利用辐射-导热耦合模式分析真空平板玻璃的传热途径,通过传热量和传热系数的计算模型,建立真空玻璃的传热控制方程,计算出真空玻璃结构沿高度方向的温度分布和热流通量,并用试验验证了理论计算结果正确性。试验结果表明,真空玻璃传热系数与真空压强成正比,真空度决定真空玻璃绝热性能;真空玻璃外面镀低辐射膜隔绝了较多的辐射热交换,其效果比内面镀膜好。     

灰葡萄孢（Botrytis cinerea）对苯醚甲环唑的敏感性及其对不同杀菌剂的交互抗药性

采用菌丝生长速率法测定了山东省和河北省不同地区的157株灰葡萄孢对苯醚甲环唑的敏感性,结果表明,其中86株野生菌株对苯醚甲环唑的敏感性（EC50值）在0.0135～1.2832μg/mL之间,相差95.05倍,平均值为（0.3958±0.3485）μg/mL,可作为敏感基线。田间已出现对苯醚甲环唑的低抗菌株,占检测总株数的9.5%,未检测到中抗菌株和高抗菌株。通过测定灰葡萄孢不同菌株对苯醚甲环唑、嘧霉胺、腐霉利、多菌灵、乙霉威和异菌脲的敏感性,发现苯醚甲环唑与嘧霉胺、腐霉利、多菌灵、乙霉威和异菌脲之间不存在交互抗性关系。