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1.
Chromium(Ⅵ) Reduction in Wheat Rhizosphere   总被引:3,自引:0,他引:3  
Reduction of Cr(Ⅵ) to Cr(Ⅲ) were studied in a fresh wheat rhizosphere soil (Kuroboku, high humic andosol) pretreated with a basal fertilizer consisting of (NH4)2SO4, P2O5 and KH2PO4 and with K2Cr2O7 by using a rhizobox system. It was found that rhizosphere exerted a positive effect on Cr(Ⅵ) reduction.Part of the reason was the decrease of pH in the rhizosphere due to application of (NH4)2SO4, implying that application of physiologically acid fertilizers would reduce Cr(Ⅵ) toxicity to plants.  相似文献   

2.
Zusammenfassung Es werden vegetationskundliche Beobachtungen mitgeteilt, die während einer botanischen Sammelreise im Herbst 1958 in Südchina in Nordostkuangsi gemacht wurden. Für dieses Gebiet sind drei Landschaftsformen charakteristisch: Kegelkarstberge, die um Kuei-lin flächenmäßig den größten Raum einnehmen; niedrige Sandsteinwellen und höhere Bergzüge aus kristallinen Gesteinen; intramontane Ebenen und Flußniederungen, beide jetzt vollständig in landwirtschaftliche Kultur übernommen.NO-Kuangsi liegt im südlichen Teil des ausgedehnten meridionalen Hartlaub-Lorbeerwaldgebietes in China, meridionale immergrüne Arten sind deshalb in Gehölzartenbestand des Gebiets vorherrschend. Die Vegetation ist fast stets durch menschlichen Einfluß devastiert, natürliche Waldreste sind nur noch kleinflächig erhalten.Die Kalkkarstberge tragen im ursprünglichen Zustand eine artenreiche Waldgesellschaft (Quercus glauca-Loropetalum chinense-Liriope platyphylla-Ass.), die im Gegensatz zur Vegetation der übrigen Standorte einen beachtlichen Anteil submeridionaler, sommergrüner Holzarten besitzt, der als Ausdruck der relativen Trockenheit der Karststandorte gewertet werden kann. Für Karstberge in fortgeschritteneren Erosionsstadien ist ein hoher Anteil vonKeteleeria fortunei typisch.Auf den sauren Verwitterungsböden der Sandsteinwellen und Kristallinberge ist jetzt nur noch buschförmige oder niederwaldartige Sekundärvegetation vorhanden (Pinus massoniana-Rhodomyrtus tomentosa-Dicranopteris-Ass.). Verschiedene Devastierungsstadien werden beschrieben, im Endstadium resultieren arme, reine Grasfluren (Imperata-Paspalum-Eremochloa-Ass.). Aufforstungen mitPinus massoniana (selten mitCunninghamia lanceolata) sind hier unternommen worden. Auf diesen Standorten wachsen fast ausschließlich meridionale Arten. Im Gegensatz dazu ist der Anteil hygrophiler, subtropischer Elemente in der Vegetation feuchter und schattiger Tal- und Schluchtstandorte innerhalb dieser Bergketten wesentlich höher, an einigen Stellen haben sich auch hier Reste der üppigen und vielschichtigen primären Waldgesellschaften erhalten (Castanopsis sp. — Camellia sp. — Alpinia chinensis-Ass.).
Summary Vegetational studies have been made during a botanical expedition through Southern China in Northeastern Kuangsi in autumn 1958. This region is characterized by three types of landscape: Coneshaped limestone karst mountains (inhabiting most of the area around Kuei-lin); low sandstone hills and somewhat higher chains of crystalline rocks; intramountaineous and river plains, the last both completely used for agricultural purposes. Northeastern Kuangsi is situated within the southern part of the expanded meridional region of broad leaved forests in China. Evergreen meridional species of the sclerophyllous and laurifoliaceous types are the predominating ones of the woody species of this region. The vegetation is nearly always devastated by human influence, natural forest relics are preserved only in small areas. The limestone karst hills are covered in the original state by a rich xerophyllous forest association (Quercus glauca-Loropetalum chinense-Liriope platyphylla-ass.). It possesses in contrary to other localities a remarkable number of submeridional summergreen trees and shrubs. Their occurrence has to be considered as the result of the relative aridity of the karst localities. On karst hills showing more progressive erosive stagesKeteleeria fortunei occurs frequently.The acid soils of the sandstone hills and the crystalline mountains are only covered by a secondary shrub vegetation (Pinus massoniana-Rhodomyrtus tomentosa-Dicranopteris-ass.). Different stages of devastation have been described, the final one is a poor grassland association (Imperata-Paspalum-Eremochloa-ass.). Afforestations were here to be seen, mostly, ofPinus massoniana, seldom ofCunninghamia lanceolata. These associations possess almost only meridional species. However in moist and shadowy valleys and ravines of these mountains many hygrophilous subtropical elements occur, here in some cases luxurious and highly differentiated primary forests have been preserved (Castanopsis sp. — Camellia sp. — Alpinia chinensis-ass.).

- , 1958 . : , ; , ; , , , .- - , , ( ë [Meusel 1959]) . , , ; . (Quercus glauca — Loropetalum chinense — Liriope platyphylla), , , , . Keteleeria fortunei. (Pinus massoniana — Rhodomyrtus tomentosa — Dicranopteris). (Imperata-Paspalum-Eremochloa). (Pinus massoniana, Cunninghamia lanceolata). . , . , -, (Castanopsis sp. — Camellia sp. — Alpinia chinensis).


Ergebnisse Chinesisch-Deutscher Biologischer Sammelreisen seit 1956 Nr. 14.  相似文献   

3.
Abstract

Numerous experiments have been conducted in Maryland and Pennsylvania since 1981 to determine if adding the nitrification inhibitor dicyandiamide (DCD) to an ammonium‐containing or producing N fertilizer source would increase the efficiency of that source with turfgrass, wheat, or corn. Greater yields per unit of fertilizer N were attained in three of eight experiments with wheat when DCD was included with an early spring application of N as urea or UAN. There was no significant beneficial effect of DCD on turf clipping yields or color in the 3 years of the turf study or on corn grain yields in the 22 field comparisons of N fertilizer with and without DCD. In five of the 22 comparisons with corn, there was a significantly lower grain yield with DCD than when it was not included. In three of these five cases, it was hypothesized that the lower yields with DCD were due to increased NH3 volatilization from urea or urea‐ammonium nitrate solutions containing DCD that were surface‐applied to no‐till corn. It was concluded that there was little likelihood that the inclusion of a nitrification inhibitor such as DCD with N fertilizer would increase N fertilizer efficiency with corn or turf on the predominantly well‐drained silt loam soils in the two states.  相似文献   

4.
The possible adverse effects on health of diet-derived advanced glycation endproducts (AGEs) and advanced lipoxidation endproducts (ALEs) is of current interest. This study had the objective of determining the effects of the addition of AGE/ALE inhibitors and different types of sugar and cooking oil on Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) formation in model foods (sponge cakes). The cake baked using glucose produced the highest level of CML (2.07±0.24 mmol/mol lysine), whereas the cake baked using fructose produced the highest concentration of CEL (25.1±0.15 mmol/mol lysine). There were no significant differences between CML concentrations formed in the cakes prepared using different types of cooking oil, but significant differences (P<0.001) were observed between the cakes prepared using different proportions of cooking oil. The cakes containing oil generated greater concentrations of CML than sucrose. α-Tocopherol and rutin did not inhibit CML and CEL formation. In contrast, ferulic acid and thiamin, thiamin monophosphate, and thiamin pyrophosphate reduced CML and CEL formation.  相似文献   

5.
The assessment of the changes in the organic carbon pool in the soils of the Russian Federation that occurred in 1990–2004 was carried out using approximation, soil-geoinformation, and simulation approaches. As a result of the changes in the system of land use, after 1990, the organic carbon storages in the 0- to 20-cm-thick soil layer could be 196–319 Mt depending on the methodology of the calculation applied and taking into account the abandoned area of 14.8 million ha. As compared to the beginning of the 1990s, the organic matter stock in the former plow layer increased by 1.6–5.8%. The great scatter of the data is mainly related to the incertainty of the estimates of the area of arable soils not used any more in agriculture.  相似文献   

6.
Tunnel cultivation of berries is increasing on a global basis, and suitable management techniques are being studied for growing berry crops in a protected environment. Soil mulching and irrigation are among the techniques that significantly affect plant growth and yield. Tunnel cultivation is often limited to growing single cultivars, and little attention has been paid to the effects of growing several cultivars in the same tunnel. There are indications that crop yield and quality might benefit from cross-pollination. In this study, the effects of artificial self- and cross-pollination were studied in 15 strawberry and 6 red raspberry cultivars grown in a protected environment in a greenhouse. Four strawberry cultivars benefited from cross-pollination and one required it. In the case of raspberries, self- and cross-pollination had no effect on yield and fruit quality. In conclusion, particular berry cultivars are better suited to tunnel cultivation.  相似文献   

7.
Mercury (Hg) transport was studied in a river in Kobbefjord, near Nuuk in West Greenland, during the 2009 and 2010 summer periods. The river drains an area of 32?km2, and the Kobbefjord area is considered representative to low-Arctic West Greenland. The river water origins from both precipitation and melting of small glaciers and annual water discharges for 2009 and 2010 were estimated to be 29 and 26 million?m3, respectively. Mean Hg concentrations (±SD) were 0.46?±?0.17 and 0.26?±?0.17?ng?L?1 for 2009 and 2010. The annual Hg transport was estimated to 14 and 6.4?g, corresponding to a transport rate of 0.45 and 0.20?g Hg km?2?year?1 from the river basin. The highest Hg concentrations (up to 1.0?ng?L?1) and discharges were measured in spring 2009 along with melting of extensive amounts of snow deposited during the 2008?C2009 winter period. In contrast, the following 2009?C2010 winter period was relatively dry with less snowfall. This indicates that a major fraction of the Hg in this area is likely to come from Hg deposited along with winter precipitation (as wet deposition) released upon snowmelt. Also, the results show that while Hg concentrations were low in Kobbefjord River compared to other sub-Arctic/Arctic rivers, the annual Hg transport rates from the basin area were within the range reported for other sub-Arctic/Arctic areas.  相似文献   

8.
9.
Atmospheric deposition and surface water chemistry have been monitored intensively at 5 geologically “sensitive” sites in southeastern Canada. The sites receive differing acid inputs that span the entire range found in Canada. Surface water data collected at 9 stations from 1981 to 1993 for SO 4 2? , NO 3 ? , Alkalinity, DOC, pH, Ca2+ and Mg2+ have been analyzed to detect monotonic trends. Similarities between the temporal patterns and trends for SO 4 2? in deposition and surface water suggest that they are strongly linked at our sites. Our 13-year datasets showed significant negative SO 4 2? trends at the 3 Ontario sites and a positive trend in Nova Scotia. A climatically-induced SO 4 2? increase in northwestern Ontario has been reversed. Mobilization and export of adsorbed SO 4 2? and/or reoxidized S from the basins of central Ontario sites is delaying their recovery. Two of our 9 stations (in Quebec and central Ontario) are continuing to acidify. The 2 Nova Scotia stations have the highest DOC levels and both exhibit a decreasing trend. Ionic compensation for declining SO 4 2? varies from station to station, sometimes involving an Alk increase, sometimes a base cation decrease, and sometimes more complex combinations. Additional factors (e.g. climatic variation) also influence variable trends, and data records longer than those presently available will be needed to unequivocally verify acidification recovery.  相似文献   

10.
《CATENA》2004,55(2):183-212
The Baurières plain within the upper Drôme River basin was used to reconstruct recent changes in sediment supply in relation to changes in land use within an alpine catchment. A considerable body of archival information is available. Furthermore, the plain acts as a natural sediment trap and the reach–basin interaction has not been disrupted by human activity. Based on archival data, channel geometry measurements, dendrogeomorphological and radionuclide analysis (Cs137 and unsupported Pb210), the trends in channel change and sediment supply over the past two centuries are assessed and their causes are interpreted.Dendrogeomorphology and radionuclide profiles show that the floodplain is characterised by a decrease in sedimentation rate in the 1960s. The ex-Pb210 profiles also suggest a spatial modification of the relative contribution in sediment supply of the catchment. Bedload yields are estimated to be at least 26 m3 km−2 year−1 between 1928 and 1996 based on an estimate of storage over a channel length of 11.5 km. Archival data concerning bedload removal from traps yields an estimate of 25.6 m3 km−2 year−1 between 1993 and 2001. These two values are very comparable suggesting no major modification in bedload transport within the reach during the 20th century. If the bedload supply has not strongly decreased in the studied reach during this period, the bedload sources have changed. The volume of sediment stored in the Beaurières area between 1928 and 1996 corresponds to at least 40% of the sediment delivered by channel degradation from an upstream alluvial reach.Both changes in floodplain sedimentation as well as changes in bedload and suspended contributions from catchment sources are interpreted as responses to land use but also flow regime. Hillslope sediment production strongly decreased due to planned hillslope afforestation and torrent regulation at the end of the 19th century, and spontaneous hillslope afforestation resulting from grazing decline, mainly in the two decades following World War II. The observed change in suspended sediment supply which occurred around 1960–1965 has a clear synchronicity with spontaneous catchment afforestation following World War II. After this period, a decrease in sediment supply, a change in source, but also a decrease in peak flow, were observed.Changes in run-off are complex and cannot be caused with only land use change. Flood hydrographs underwent peak decreases and duration increases through the 20th century because of increase in water retention capacity of the forested catchment. In addition flood seasonality has changed, with September and October flood events being much less frequent in the last part of the 20th century.  相似文献   

11.
The Ogallala Aquifer is a key water resource for several U. S. states. TransCanada, a Canadian company, proposes to construct the Keystone XL pipeline to transport tar sands crude oil from Alberta to refineries in Texas; one proposed route would bury the pipeline in the Aquifer, raising water quality and environmental concerns. A rich inventory of information about the Aquifer predates the current controversy. This article presents a key subset of an extensive, ongoing bibliography: 128 citations to gray literature about the Ogallala Aquifer in Nebraska, which are inaccessible online and/or held in only a few libraries. The authors present several examples to illustrate the relevance of this gray literature to current events, comment on difficulties encountered during the bibliographic harvest and the identification of this subset, and reiterate the need for planned preservation through digitization of historical (print) gray literature.  相似文献   

12.
《Biological conservation》1986,36(4):315-328
The Wildlife and Countryside Act 1981 protected all species of bat and required that, in certain circumstances, advice be sought about them. Analysis of these enquiries produced data about their geographic distribution, the types of problem that arose, the acceptability of the advice provided, the species of bat involved and the organisations receiving the enquiries. The great majority of enquiries related to dwelling-houses and, of these, most resulted from the discovery of bats roosting in the roof.The conservation organisations, mainly the Nature Conservancy Council, proved very successful in persuading householders to leave bats undisturbed; almost all colonies were permitted to remain temporarily and many were permitted to return in succeeding years. Repairs or remedial timber treatment to roofs used by bats were also important sources of enquiries and detailed advice was provided. Most enquiries came from southern England, with a sustained decline towards the north. Pipistrelles were the most common species, followed by long-eared bats. The other 13 species appeared to be involved in relatively few cases.  相似文献   

13.
Abstract

The quantitative reduction of nitrate in an acid medium with reduced Fe was applied to the alkaline permanganate solution used to absorb NO and NO2 evolved from soils during denitrification reactions. The method involves addition of H2SO4 to acidify the solution and ensure oxidation of nitrite to nitrate, and treatment with reduced Fe at 100°C to reduce nitrate to ammonium. The solution is made alkaline with NaOH and ammonium determined by standard distillation procedures. It is simple and precise, and applicable to nitrogen isotope ratio analysis of NO and NO2 evolved from soils.  相似文献   

14.
OPG是一种分泌型糖蛋白,属于TNF受体超家族成员,可抑制破骨细胞分化的最终阶段以及成熟破骨细胞的活性并诱导其凋亡(Simonet et al.,1997;Yasuda et al.,1998)。目前,国内外尚未见有关鸡OPG克隆的相关研究报道。本实验在体外成功地培养鸡胚额骨成骨细胞的基础上(张胶和侯加法,2  相似文献   

15.
(英文)     
对来源于美、中、俄及埃塞阿比亚等22个国家的142份硬粒小麦材料的种子贮藏蛋白位点及遗传变异进行了研究。供试的硬粒小麦(Triticum durum Desf )材料共检测出37条醇溶蛋白条带,无1条带纹为所有材料共有,多态性达到100%,说明硬粒小麦具有丰富的醇溶蛋白等位变异。聚类分析将142份供试材料分为3个大类,材料间遗传差异大小在不同的国家有所不同,表明醇溶蛋白带型与地理来源有一定关系。高分子量谷蛋白电泳共分离出14种亚基和15种亚基组合,但是优质亚基所占比例不高,这可能是因为硬粒小麦加工用途的特殊性,使得多年的育种并未太多改变硬粒小麦高分子量谷蛋白亚基等位变异的频率,促成优质亚基的累计。  相似文献   

16.
(英文)     
为了揭示猪杂种优势的分子机理,利用mRNA差异显示技术研究梅山猪,大白猪和梅大杂交猪背最长肌中基因表达的差异, 分离14条在杂种与纯种背最长肌中差异表达的表达序列标签(EST), 并用半定量RT-PCR鉴定。核苷酸序列分析表明, 这14个EST与已知的基因或表达序列标签没有明显的同源性,随后这14条EST 被提交到GenBank数据库。组织表达谱分析揭示了这些EST在心、脾、 肝、肾 、 小肠、 卵巢、 肺等绝大多数组织中表达, 说明这些基因对生命过程很重要。这些研究结果表明梅山×大白杂交组合的杂种与纯种之间的不同基因差异表达的方向存在巨大差异,猪杂种优势可能是在一定阶段有诸多不同的必不可少的基因向各种方向差异表达共同作用的结果。  相似文献   

17.
Remarkable morphological variation has been found within small Eritrean barley fields. Barley was collected from fields approximately 50 m2 in size. Spike shape, type, and colour were observed to vary both between and within fields. A set of 39 Simple Sequence Repeats (SSR) markers were used to explore the genetic diversity of the Eritrean barley collected from small-scale farmer’s fields. Significant genetic diversity was found within the barley fields. Out of 240 spikes collected from 24 fields (10 spikes per field), only two spikes from geographically distant fields were genetically similar. Based on the SSR data, individual farmers’ fields were found to possess 97.3% of the genetic variation present in the Eritrean barley. We discuss a strategy to improve the barley yield in Eritrea, and to facilitate the in situ conservation of barley genetic diversity. Gunter Backes and Jihad Orabi contributed equally to this work.  相似文献   

18.
(英文)     
用SDS-PAGE方法测定了我国10个小麦主产省份171份小麦品种和高代品系的高分子量麦谷蛋白亚基(HMW-GS)组成。鉴定出18种HMW-GS,40种HMW-GS组成形式,其中20种亚基其组成形式只在一个品种(系)中出现。Glu-A1位点亚基1和Null出现最多,Glu-B1位点7+8和7+9亚基对占绝对优势,Glu-D1位点2+12亚基对出现频率最高。Null、7+9、2+12、Null,7+8,2+12,1、7+8,2+12,1、7+9、2+12等亚基组成形成出现频率最高,占分析品种的49.71%。与前人研究相比,新育成品种HMW-GS亚基组成发生了明显变化,面包优质亚基(对)1、5+10出现的频率显著升高,亚基多态性增加,组成形式明显改善,这些对于品质改良和品种选育是非常有利的,新育成品种Glu-1品质评分已超过7。尽管个别品种亚基组成好,品质优良,但总体上看,我国小麦品种与其它国家相比品质还存在一定差距,提高5+10、17+18等优质亚基的频率是改善我国小麦面包品质的重要措施。  相似文献   

19.
Cervelli  S.  Di Giovanni  F.  Perna  C.  Perret  D. 《Water, air, and soil pollution》2000,124(1-2):125-139
An isotopic model (NISOTOP) has been developed to investigate the effect of the addition to soil of xenobiotics on urea hydrolysis, N mineralization and immobilization, nitrification and plant uptake of nitrogen in a soil-plant system, after addition of 15N enriched compounds. Therationale of the model follows from the errors in %15N abundance (15N D) and N concentration (CN) determinations which cause high variability coefficients in the calculation of the amount of nitrogen present in the different compounds derived from the added 15N enriched urea. The extent of these errors, besides depending on CN and 15N D errors, will also depend on natural 15N and 15N of the added compound, and therefore on the experimental conditions. The model is described by 18 first-order differential equations and is numerically solved by Euler's method with a time increment of 0.01 day. As an illustration, the model is applied to the effect of phenanthrene, chrysene and benzo(a)pyrene to a soil-plant system, following the addition of 15N-urea. These compounds have been chosen as examples of molecules having 3, 4 and 5 fused aromatic rings and are hereafter collectively referred to as PAHs. PAHs at the rate of 2 mg kg-1 soiland 15N-urea at the rate of 166.7 mg N kg-1 soil were added to wheat pots. At harvesting (after 14 days from plantation) the dry matter yield, the total N content and the N concentration of the wheat seedlings were not statistically affected by addition of the PAHs (P = 0.05). The efficiency of N uptake, that is the percentage of fertilizer taken up by the plants at harvesting in the absence of PAHs was 47.3%, while it was 11.7, 15.2 and 14.8% in the presence of phenanthrene, chrysene and benzo(a)pyrene,respectively. The computation of the first-order rate constants of the N transformations showed that N mineralization, nitrification and N-uptake were affected by the addition of phenanthrene, chrysene and benzo(a)pyrene, whilst benzo(a)pyrene inhibited urea hydrolysis more than phenanthrene and chrysene.  相似文献   

20.
Red–yellow (Pisum fulvum Sibth. et Sm.) and Ethiopian (Pisum abyssinicum A. Br.) peas have become of increasing interest to breeders in the last decade, as they have been found to be partially or completely tolerant to various biotic stresses, such as to attack by pea weevil, mildew blight or rust. A trial was carried out at the Institute of Field and Vegetable Crops at Rimski ?an?evi from 2005 to 2007, with 13 accessions each of red–yellow and Ethiopian peas sown at 100 viable seeds m?2, in plots of 0.5 m2. Seed yield per plant in red–yellow pea was significantly and positively correlated with seed number per plant (r = 0.881**), pod number per plant (r = 0.839**) and number of fertile nodes (r = 0.820**). The highest positive correlation among the agronomic characteristics in Ethiopian pea was between number of fertile nodes and number of pods (r = 0.937**). Seed yield in Ethiopian pea was highly significantly correlated with number of seeds (r = 0.807**), pods (r = 0.692*), and fertile nodes (r = 0.638*). The results suggest that plant morphology of the progenies between red–yellow or Ethiopian peas and grain-type common pea could not differ significantly from that of individual parents. That means that it could be possible to develop hybrid lines that could keep the desirable morphological traits of grain-type common pea, such as lodging-tolerance and high seed yields, and to make an introgression of a specific resistance from wild pea taxa, especially by back-crosses with the former. However, one must always be aware of unpredicted outcomes as a result of rather different genetic basis of individual seed yield components.  相似文献   

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