Mehlich3-连续流动分析仪在砖红壤有效磷和有效钾测定上的应用

以采自海南省橡胶园的5种母质51个土壤样品为对象,研究了Mehlieh3法浸提-AA3型连续流动分析仪(M3-AA3)联合测定砖红壤有效磷(P)和有效钾(K)的可行性.结果表明,M3法提取的有效磷(y)与常规Bray2-P (x)呈极显著相关(y=0.626 6 x+0.934 1,R2＝0.980 6,p＜0.01,...     

磷肥在海南岛砖红壤中的转化和肥效

本文应用土壤无机磷形态的分级方法,研究了海南岛热作土壤(即热带旱作土壤,以下同)无机磷的形态和磷肥在土壤中的转化及肥效。初步结果表明海南岛热作土壤无机磷以闭蓄态磷酸盐(Occluded phosphate 即O—P)为主体,其含量占土壤无机磷总量50％以上。非闭蓄态磷酸盐(Non-occluded phosphate即非O—P)则以磷酸铁(Fe—P)为主,其次是磷酸钙(Ca—P)和磷酸铝(Al—P)。土壤有效磷(Bray No.1法提取,以下同)大都在3～15ppm,仅占非O—P的3～10％。因此海南岛热作土壤普遍缺磷,施磷肥的效果显著。自然土壤有效磷与土壤Al—P相关极显著。与Fe—P相关不显著,而与Ca—P和O—P呈负相关。水溶性磷肥(过磷酸钙)在热作土壤中主要向非O—P转化,肥料与土壤充分混合盆栽两个月后,土壤O—P没有明显增减,而非O—P特别是Fe—P、Al—P则显著增加。施肥后土壤Fe—P、Al—P与土壤有效磷和作物吸收磷量相关显著,说明磷肥在土壤中转化形成的非O—P在一个相当长的时间内(至少当造)对作物是有效的,而不是很快“固定”失效。因此,对热作土壤中磷酸铁、铝的性质和磷肥的施肥方法值得进一步探讨。     

花生因土施用钾肥研究初报

在花生产区设置13个田间试验并测定土壤有效养分。结果表明,花生施钾肥的效果与土壤有效钾含量极不显著,而与土壤有效磷含量呈明显的正相关关系。采用逐步回归法统计结果,说明花生增产应强调钾与磷素营养的协调。根据回归方程算出,本区花生钾肥应用于缺钾区,亩施     

茶园土壤磷素营养评价指标的探讨

茶树系“好酸作物”,在酸性较强的红黄壤上可以较好地生长。这种土壤对磷的自然固定能力很强,因此,土壤中有效磷含量很低。茶树由于长期自然选择的结果,为了适应这种低磷的环境,形成了对磷吸收的自身特点。据研究,茶树不仅能吸收土壤中的水溶性磷,而且还能吸收与铁、铝、钙结合的难溶性磷,甚至对原生矿物晶格中的某些磷也有一定的吸收利用能力。长期以来,在衡量茶园土壤磷的有效程度时,往往沿用各种作物都通用的测定土壤有效磷含量的方法。但是,通过对茶园土壤磷素营养状况的大量研究和多年的生产实践发现,由于茶树对磷的吸收利用能力比其他作物强,用一般方法测定有效磷含量很难反映茶园上壤实际的供磷能力,因此有必要制定出     

施用不同豆科绿肥对酸性土壤无机磷分级的动态影响

采用尼龙袋法,研究酸性土壤施用4种豆科绿肥(尖叶木蓝、铺地木蓝、扁豆与链荚豆)后,在1年内不同时间,土壤无机磷各组分含量的动态变化。结果表明:不同绿肥对于土壤无机磷影响的效果存在显著差异,但总体上施用豆科绿肥可显著降低酸性土壤无机磷的总量,对于土壤无机磷各组分,施用绿肥可显著增加土壤铁磷(Fe-P)以及铝磷(Al-P)的含量,但显著降低土壤中钙磷(Ca-P)以及闭蓄态磷(O-P)的含量;施用绿肥对于土壤无机磷的影响随施肥时间的变化而不同。     

土壤有效磷含量对大豆植株磷素含量和土壤有效N、P、K含量的影响

土壤有效磷含量影响大豆植株对N、P、K的吸收利用,进而影响大豆植株的生长发育和产量形成。以吉育89为材料,在大豆不同生长时期测定大豆植株磷素含量和土壤N、P、K含量,研究其随土壤有效磷含量升高而发生变化的规律。结果表明:在取样的4个时期里,植株磷素含量均随土壤有效磷含量的升高呈单峰曲线变化,在土壤磷素水平为30 mg·kg~(-1)时,植株磷素含量达到最大;5个处理的土壤速效磷含量变化趋势都是先下降,在收获期由于土壤自身的磷素补偿作用而有所升高;在各生育时期的土壤中的硝态氮和速效钾含量最低值都出现在有效磷含量为30 mg·kg~(-1)处理,而土壤速效磷含量为10和50 mg·kg~(-1)两个处理的硝态氮和速效钾含量一直较高,说明低磷和高磷土壤对植株氮素吸收有抑制作用。土壤有效钾含量的变化情况与硝态氮相似,均是随土壤有效磷含量升高而呈单峰曲线变化。说明N、P、K肥的合理配比均能够提高肥料的作用效果。     

Olsen法测定蔗区土壤有效磷影响因素研究

为了提高蔗区土壤用碳酸氢钠浸提-钼锑抗比色法(简称Olsen法)测定有效磷含量的精密度和检测效率,本文对Olsen法测定土壤样品有效磷时比色皿的选择、浸提温度、浸提土液比、振荡频率和振荡时间等影响因素进行了分析研究,结果显示当样品浓度较小时,应选用光程长度较大的如2、3cm比色皿,反之,选用光程长度较小的如1 cm比色皿;为保持显色时待测液的酸度,在加入显色剂前,需先调节浸提液的pH至微黄色,以保证实验结果的准确性;选择最大吸收波长700 nm处作为测量波长,以获得较高的灵敏度及较好的线性关系。在土液比1∶20,振荡时间30 min,振荡频率180±20 r/min,浸提温度25±1℃等条件下测定蔗区土壤样品有效磷最为理想,测定土壤样品有效磷含量的RSD为0.41%～1.22%,符合标准要求。与NY/T 1121.7-2014相比,本方法缩短了实验时间,增加了实验结果的稳定性,优化了环境对实验的限制。     

海南热带土壤对磷的吸附特性与施磷量的关系

对海南岛主要类型土壤磷的等温吸附曲线、“磷肥指标”的测定和盆栽试验结果表明:海南岛热带土壤对磷的最大吸附量差异很大,吸附容量愈大,其“标准需磷量”愈高,但是最大吸附量与标准需磷量的比率,则与吸附系数有关;各类土壤施磷量与土壤有效磷提取量呈直线相关,其斜率“b”称为“磷肥指标”,“b”愈大,磷肥的有效程度愈低,要达到一定有效磷水平所需要的施磷量也愈大;各类土壤盆栽花生最高生物量(干重)所对应的施磷量与两种方法预测的土壤需磷量相近,证明应用该两种方法预测热带土壤的需磷量是可行的;缺磷土壤初时的施磷量必须达到一定水平才显肥效。     

利用连续流动分析仪快速测定碱熔法土壤全磷

根据 AA3 型连续流动分析仪（简称 CFA）测定磷的原理,研究了用 CFA 快速测定碱熔法待测液中土壤全磷 的方法。结果表明：通过优化 CFA 进样冲洗液及显色液的酸度,土壤全磷的标准曲线,在 0~8 mg/L 范围内呈线性相 关,相关系数 R2 达 1.000 0;全磷含量不同的 3 个土壤样品待测液 10 次重复测定结果变异系数≤2.0%;样品加标回收 率为 99.08%~102.42%;土壤成分分析标准物质 GBW07408 土壤全磷 CFA 法测定结果与其参考值一致,CFA 法与碱熔 钼锑抗手工比色法测定结果无显著差异。且由于 CFA 法去除了手工法中显色前样品酸度的调节步骤,因此 CFA 法具有 快速、准确测定碱熔法待测液中土壤全磷的效果。     

酸性茶园土施用石灰对磷酸盐的转化与效应

采用实验室接种培养方法,研究了施用石灰对水溶性磷、无机磷组分的转化和酸性土中Bray-1有效磷的影响。结果看出:施用石灰能显著地增加未施磷土壤的水溶性磷或速效磷,以增加未施磷和施用磷肥土壤的铝磷盐组分( fraction)。但对土壤中铁和钙磷盐组分的影响,则相对地少得多。酸性土壤施用石     

Pharmacokinetics of Marine-Derived Drugs

Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future.     

La pourriture fongique des tubercules de pomme de terre en atmosphère contrôlée

Résumé Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.

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Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.

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Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O₂:1% CO₂, 2% O₂:6% CO₂, 2% O₂:12% CO₂, 6% O₂:6% CO₂). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.

     

Marine Pharmacology in 2016–2017: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis and Antiviral Activities; Affecting the Immune and Nervous Systems,and Other Miscellaneous Mechanisms of Action

The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories.     

Effects of Micronutrient Deficiencies on Human Health: Its Status in South Asia

SUMMARY

Vitamin A, iodine, and iron deficiencies affect large numbers of people worldwide. A deficiency of one or more of these micronutrients adversely affects the physical and mental abilities of humans. South Asia contains a high percentage of these individuals, not just because of its large population, but also the prevalence of deficiency is higher there than in many other parts of the world. The reasons for the high rates of deficiency in South Asia are many, but they include inadequate availability of micronutrient-rich foods, sub-optimal dietary habits, and high rates of infection. Across the region, national plans vary from (a) increasing availability of appropriate foods, (b) introducing new dietary behaviors, (c) improving health status, and (d) directly addressing deficiency through intervention programs. The extent to which each of the countries is making progress toward the goals of these plans can help in understanding the priorities for future efforts to address micronutrient malnutrition. This article discusses the adverse effects of micronutrient deficiencies in humans with special reference to South Asia.     

Management of Soil Micronutrient Deficiencies in the Rice-Wheat Cropping System

Summary

Within the last three decades, the rice-wheat cropping system has triggered, and with time, aggravated soil micronutrient deficiencies in the Indo-Gangetic Plains (IGP). This has largely been due to the shift from an earlier rice and wheat monoculture with low yielding, long duration indigenous varieties, to an intensive rice-wheat rotation cropping system with short duration modern high yielding varieties on the same piece of land. The problems related to micronutrient deficiency in the IGP are more due to the size of its available pools in the soil rather than its total contents and are greatly influenced by crop management, or rather its mismanagement. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, zinc deficiency has reduced in some areas of the region. Meanwhile, the deficiency of Fe, Mn and B has increased in the IGP. Deficiency of Cu and Mo is location specific and can limit rice and wheat yields. The adoption and spread of the rice-wheat system in permeable coarse textured soils, particularly in the western IGP, not only caused iron deficiency in rice but also resulted in the emergence of manganese deficiency in wheat. In highly calcareous and acidic soils, boron is the next limiting micronutrient in crop production after zinc. Bumper rice and wheat harvests in the past decade, the declining use of organic manures in the region and except for the widespread use of zinc sulfate, a general lack of awareness amongst farmers on micronutrient deficiency problems has contributed to micronutrients limiting rice and wheat yields in the IGP. Approaches to alleviating micronutrient deficiencies include matching the crop removals of the micronutrients with its replenishments through their respective external carriers, supplementation through organic sources and mobilization/utilization through cultivation of micronutrient efficient crop cultivars. Identification of efficient micronutrient carriers and finding the optimum rate, mode and time of its application is important in ameliorating the micronutrient deficiencies. This article reviews the extent of micronutrient deficiency and discusses various management options available to reduce micronutrient deficiency induced crop yield reduction for rice and wheat in the Indo-Gangetic Plains.     

Irrigation but not N fertilization enhances seedhead density in plains rough fescue ( F estuca hallii)

Plains rough fescue ( F estuca hallii) is an important forage grass species in western Canada. Seed for use in pastures and ecological restoration is in high demand but supply is limited because F. hallii is an erratic seed producer. Seed producers require an understanding of the factors that influence flowering and seed set in this species. The aim of this study was to assess the effect of irrigation and nitrogen fertilization on the flowering and growth of F. hallii in a native rough fescue prairie in Alberta, Canada. Irrigation had a strong positive effect on seedhead density, whereas fertilization had limited effects on growth and reproduction of F. hallii. These results demonstrate that under field conditions, available moisture is likely to be a key factor driving flowering and seed production in F. hallii.     

Marine Drugs Regulating Apoptosis Induced by Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL)

Marine biomass diversity is a tremendous source of potential anticancer compounds. Several natural marine products have been described to restore tumor cell sensitivity to TNF-related apoptosis inducing ligand (TRAIL)-induced cell death. TRAIL is involved during tumor immune surveillance. Its selectivity for cancer cells has attracted much attention in oncology. This review aims at discussing the main mechanisms by which TRAIL signaling is regulated and presenting how marine bioactive compounds have been found, so far, to overcome TRAIL resistance in tumor cells.     

Biochemical and morphological characterization of potato clones differing in their resistance to late blight

Summary Morphological and biochemical parameters that could be involved in resistance to late blight were studied in non-infected and in infected potato hybrids resulting from a cross betweenSolanum phureja, resistant toPhytophthora infestans, and a susceptibleSolanum tuberosum. Some morphological differences between resistant and susceptible hybrids, indicating a positive correlation between stem diameter and phloem thickness in the stem and resistance toP. infestans, were observed. The lignin content in the leaves of the resistant hybrid rose upon infection byP. infestans. In the leaves of the susceptible hybrid, a diminution of the lignin content could be observed upon infection byP. infestans. In the same context, peroxidasic activity raised upon infection byP. infestans in both resistant and susceptible hybrids. Further characterization of the hybrid clones based on the polymorphism of peroxidases was attempted using isoelectric focusing.     

Applied Biotechnology to Combat Late Blight in Potato Caused by <Emphasis Type="Italic">Phytophthora Infestans</Emphasis>

Potato is an important crop, grown worldwide. It suffers from many pests and diseases among which late blight, caused by the oomycete Phytophthora infestans, is the worst. The disease is still causing major damage in many potato production areas and control is only possible by applying fungicides frequently. The knowledge on the molecular biology and genetics of the interaction between the plant and the oomycete is developing rapidly. These are relevant fields of study, currently dominated by the discovery of many resistance genes and numerous effector proteins and the analysis of their specific mode of action. These studies may yield essential information needed for the development of durable resistance. The long-term and worldwide effort to breed for resistance so far has had little effect. A novel breeding approach may change this. It is based on cisgenic modification (CM) consisting of marker-free pyramiding of several resistance genes and their spatial and temporal deployment yielding dynamic varieties that contain potato genes only. It is envisioned that this CM approach with potato’s own genes will not only prove societally acceptable but may also result in simplifications in the legislation on use of the CM approach. Various parties in the potato research arena intend to cooperate in this novel approach in a number of developing countries where potato substantially contributes to food security. The use of resources such as land, water and energy improves when the effect of late blight is markedly reduced.     

Resistance to <Emphasis Type="Italic">Potato virus Y</Emphasis> in a Multitrait Potato Breeding Scheme without Direct Selection in Each Generation

In an experimental breeding scheme to improve late blight (Phytophthora infestans) and white potato cyst nematode (Globodera pallida) resistance of tetraploid potato over three generations of crossing and selection, 15 clones survived the final selection, and these were derived from 15 great-grandparents. There was no direct selection for resistance to Potato virus Y (PVY), but 14 out of the 15 great-grandparents were resistant to PVY and three had extreme resistance. Thirteen of the 15 descendants had PVY resistance and one extreme resistance. This was within the range expected for a random (unselected) sample from the genotypes of the great-grandparents. Hence, we found no evidence for any positive or negative association between PVY resistance and the attributes selected. The conclusion is that laborious selection is not required in every generation when many parents have PVY resistance, including some with more than one copy of a PVY resistance gene or resistance at more than one locus. However, in the future, determining the major virus resistance genes present in potential parents in each generation using diagnostic molecular markers would prevent susceptible × susceptible crosses being made and maximise the number of resistant × resistant ones.