Effect of iron and manganese on65Zn absorption and translocation in soybean seedlings

Summary Short-term experiments were conducted to determine the effect of varying levels of iron and manganese on⁶⁵Zn absorption by roots and translocation to shoots in soybean seedlings. In 11 hours uptake duration, both iron and manganese depressed the⁶⁵Zn absorption by roots and translocation to shoots. The depression was of higher magnitude at higher levels of iron and manganese (5.0 ppm) in the medium coupled with highest level (5.0 ppm) of zinc concentration. It is concluded that interactions between zinc and iron as well as zinc and manganese occur during absorption and translocation processes.Publication No.1185 under Journal Series of the G.B. Pant University of Agriculture and Technology, Experiment Station, Pantnagar     

Chemical methods of estimating plant available manganese in soils

Summary Twelve different chemical extraction procedures for extracting soil manganese were used. Soil test values determined for fourteen representative soil samples of Rajasthan State with manganese uptake by six crop species have shown that of the extractants used, 3N ammonium dihydrogen orthophosphate can be best used for estimating plant available soil manganese.     

Principles and problems of the chemical estimation of the supply of available soil manganese

Summary The principles and problems involved in the estimation of the supply of available soil manganese are summarized. Methods have been developed mostly on the basis of a single manganese fraction, but more recently there have also been suggestions of using other single factors or even several factors influencing the supply of available manganese. More important than the suggestion of an extractant is the evaluation of a new method,i.e. the calibration by means of a suitable standard.     

The role of organic matter in soil manganese equilibrium

Summary Tests were conducted to determine the role of additions of fresh organic matter (ground cotton seed hulls) to an alluvial loam soil of pH 8 on manganese equilibrium. It was shown that organic matter has a reducing potential which, when added to the soil, resulted in a rapid and marked increase in exchangeable manganese. The reduction is enhanced by higher temperatures (21.1vs 37.7°C) and additions of water (field capacityvs air dry) and incubation periods up to 3 days. It is suggested that the shift in the soil manganese equilibrium, induced by such factors as waterlogging or anaerobic conditions, will be more pronounced when soils contain high levels of organic matter.Patterns of the standard deviations of sample exchangeable manganese data within treatments showed that the variance is highest in moist soil, lower concentrations of added organic matter, and at longer durations of incubation. Re-oxidation of manganese occurred at lower levels of added organic matter (2 and 4%) and extended incubation time (5 to 9 days).The investigation reported in this paper (67-10-36) is in connection with a project of the Kentucky Agricultural Experiment Station and is published by permission of the Director.     

Sporulation ofBacillus subtilis as a possible measure of available manganese in calcareous soils

Summary Sporulation ofBacillus subtilis ATCC 9799 in nutrient broth was correlated with Mn⁺⁺ concentrations at 10^–7 to 10^–6 M. This specific response was employed for the bioassay of plant available soil manganese. A correlation between sporulation ofB. subtilis in growth medium supplemented with soil samples sterilized by gamma rays or by ethylene oxide, and growth response ofAvena sativa to added manganese was observed in 5 of 6 loessial and rendzina highly calcareous soil types. No correlation between chemical tests and response to manganese fertilization of this soil could be observed.The possible use of this method for the bioassay of plant-available soil manganese is discussed.     

Soil properties of Alhagi sparsifolia community in saline-sodic badlands in west China

A field experiment was conducted to assess the influences of soil chemical, physical, and biological properties of Alhagi sparsifolia community in Linze, Gaotai, and Guazhou County, Gansu province, China. Results showed that soils sampled were generally infertile with low levels of organic matter, available nitrogen, phosphorus, copper, manganese, and zinc with bacteria dominant microbial communities supporting A. sparsifolia. Available potassium and iron were sufficient in the study sites. With increasing soil layer depth, the contents of organic matter, available nitrogen, phosphorus, potassium, manganese, urease, dehydrogenase, bacteria, and actinomyces in the soil decreased significantly (P < 0.05), whereas the concentrations of moisture, available iron, and zinc in the soil increased significantly (P < 0.05). The contents of organic matter, available nitrogen, phosphorus, potassium, iron, manganese, zinc, copper, urease, dehydrogenase, bacteria, and actinomyces showed strong seasonal variations (P < 0.05). All these variables except dehydrogenase, bacteria, and actinomyces were the highest in summer and the lowest in spring. The comprehensive score of soil qualities was the greatest in Linze, medium in Guazhou, and lowest in Gaotai.     

Survival from five common cancers in Georgia, 2015–2019 (CONCORD)

BackgroundPopulation-based cancer survival is a key metric of the effectiveness of health systems in managing cancer. Data from population-based cancer registries are essential for producing reliable and robust cancer survival estimates. Georgia established a national population-based cancer registry on 1 January 2015. This is the first analysis of population-based cancer survival from Georgia.MethodsData were available from the national cancer registry for 16,359 adults who were diagnosed with a cancer of the stomach, colon, rectum, breast (women) or cervix during 2015–2019. We estimated age-specific and age-standardised net survival at one, two and three years after diagnosis for each cancer, by sex.ResultsThe data were of extremely high quality, with less than 2% of data excluded from each dataset. For the patients included in analyses, at least 80% of the tumours were microscopically verified.Age-standardised three-year survival from stomach cancer was 30.6%, similar in men and women. For colon cancer, three-year survival was 60.1%, with survival 4% higher for men than for women. Three-year survival from rectal cancer was similar for men and women, at 54.7%. For women diagnosed with breast cancer, three-year survival was 84.4%, but three-year survival from cervical cancer was only 67.2%.ConclusionEstablishment of a national cancer registry with obligatory cancer registration has enabled the first examination of population-based cancer survival in Georgia. Maintenance of the registry will facilitate continued surveillance of both cancer incidence and survival in the country.     

Effect of rice based six multiple cropping sequences under two cycles of crop rotations on yield and fertility status of soil

A field experiment was carried out to study the effect of various crop rotations, of high yielding varieties of cereals, pulses, fodders, tubers and oilseeds, on the performance of the crops and the fertility status of the soil over two crop-rotation cycles. The yields of rice (Oryza saliva L.), potato (Solanum tuberosum L.) and onion (Allium cepa) crops were found to be decreasing. The yields of wheat (Triticum aestivum L.) and mustard (Brassica juncea coss), were not affected, while the yield of moong (Phaseolus aureus Roxb.) showed a tendency to increase. Rotations which included berseem (Trifolium alexandrinum) increased the organic carbon content of the soil and there was a slight lowering of the pH with the highest application of phosphatic fertilizer. The accumulation of available potassium was greater in the treatments where the highest amount of fertilizer was applied. The available nitrogen content of the soil increased with application of nitrogen and the balance sheet of nitrogen, phosphorus and potassium showed a positive trend. The continuous cropping of high yielding varieties showed a reduction in the available zinc and iron status of the soil, whereas available manganese and copper increased. The available micronutrients, except manganese, did not correlate significantly with soil pH.     

The properties of a biologically formed manganese oxide,its availability to oats and its solution by root washings

Summary Manganese oxide, produced byCorynebacterium sp. in liquid medium was found to be amorphous, probably hydrated and was readily reduced by neutral quinol. Preparations of the oxide had values of n in the formula MnO_n which ranged from 1.76 to 1.88. The oxide was completely available to oats grown in sand culture but only slightly available in a manganese deficient soil. Plants grown under sterile conditions on agar slopes were able to obtain manganese from manganese oxide, indicating that the roots and not associated micro-organisms, were responsible for the solution process. Root washings of oat plants contained substances which dissolved manganese oxides and the activity of these substances increased with increasing acidity. The possible importance of these substances in making soil manganese available to plants is discussed.     

The effects of lime and superphosphate on manganese toxicity in steam-sterilized soil

Summary The effects of liming and superphosphate application on the manganese nutrition of lettuce were studied in factorial experiments. A fairly acid silt loam of the Hamble series, which on steam-sterilization released considerable amounts of manganese in readily available forms, was used in the investigation.Manganese toxicity in lettuce was prevented by liming to increase the pH of the soil. The amounts of water-soluble, exchangeable and total active manganese present in the soil, and the manganese content of lettuce plants, decreased with increasing soil pH; easily reducible soil manganese increased with increasing soil pH.The effect of added superphosphate depended on the pH of the untreated soil. When the soil had a high pH, application of phosphate invariably decreased the pH and increased the manganese uptake. In acid soil supplying excessive amounts of manganese, application of phosphate reduced the manganese content of the plants; the pH of the soil was either unchanged or slightly increased by the treatment.Correlations were calculated between soil pH, various fractions of soil manganese, and the manganese content and yield of lettuce.From a comparison of plants grown in soil and sand culture it was concluded that the presence of a further toxic factor in the soil was probable.The results are discussed in relation to those obtained by other investigators.     

土壤理化性质驱动烤烟根际细菌群落的组配及其共现性网络互作

【目的】解析土壤微生物在植物根际的组配机制对于认识和维护农田生态系统的稳定性至关重要。【方法】通过Illumina高通量测序和生物信息学分析方法明确了我国主要种植烟草生态区烤烟根际土壤细菌群落与土壤理化性质的互作关系。【结果】烤烟根际细菌类群主要为放线菌纲(Actinobacteria)、α-变形菌纲(Alphaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)和嗜热油菌纲(Thermoleophilia)。细菌群落组成按生态区聚类,且样本空间距离和细菌群落相似度显著负相关。共现性网络分析表明,烤烟根际细菌群落间协同作用大于拮抗作用,武陵秦巴生态区、黄淮平原生态区、南岭丘陵生态区和沂蒙丘陵生态区细菌群落高度模块化,小单胞菌属(Micromonospora)为南岭丘陵生态区和黄淮生态区细菌共现性网络的网络中心,Bryobacter和气单胞菌属(Arenimonas)为南岭丘陵生态区细菌网络的模块核心,其菌群特性而非相对丰度决定了其在稳定细菌网络中的重要作用。冗余分析结果证实pH、有效铁、交换性镁和有效锰能显著影响烤烟根际细菌群落结构。【结论】烤烟根际细...     

Effects of arbuscular mycorrhizal fungi on the growth and heavy metal accumulation of bermudagrass [Cynodon dactylon (L.) Pers.] grown in a lead–zinc mine wasteland

Abstract

A pot experiment was conducted to investigate the potential influence of arbuscular mycorrhizal fungi (AMF), Funneliformis mosseae and Diversispora spurcum, on the growth and nutrient (P and S) and heavy metal (HMs) (Pb, Zn, and Cd) content of bermudagrass [Cynodon dactylon (L.) Pers.] in a lead-zinc mine wasteland. The D. spurcum inoculation significantly increased the bermudagrass growth, whereas the F. mosseae inoculation did not. The AMF inoculation significantly increased the soil pH and uptake of P, S, and HMs by bermudagrass, decreased the contents of available Pb and Zn in soils and Pb in shoots, reduced the translocation factor (TF) and translocation capacity factor (TF') of Pb and Cd in bermudagrass and increased the TF and TF' of Zn in bermudagrass. A significant negative correlation was found between pH and available HMs in soil, whereas a significant positive correlation was noted between the HMs content and nutrient content in bermudagrass shoots. Experiment results provide evidence of the potential role of AMF in improving bermudagrass performance for the vegetation restoration of metalliferous mine wastelands.     

长期连作农田土壤细菌群落结构和共现网络拓扑性质对土壤理化性质的响应

【目的】为探究长期连作土壤细菌群落结构和分子生态网络与土壤环境演化的关联性。【方法】本研究利用16S rRNA基因高通量测序技术,解析了湖南省浏阳市两块连作十二年农田(表现连作障碍的GD和健康的YA)土壤微生物群落组成结构和分子生态网络拓扑性质与土壤理化性质的关系。【结果】GD土壤总氮和有效磷含量显著高于YA,而土壤硝态氮和速效钾含量显著低于YA(P<0.05)。GD土壤细菌群落多样性高于YA,两地土壤细菌群落结构存在显著差异(P<0.01),且与土壤pH和有效磷含量相关。进一步分析表明,GD土壤细菌群落之间比YA具有更复杂的生态网络,主要体现在能量代谢、碳循环和氮循环功能模块。【结论】综上所述,连作会引起土壤细菌群落多样性、组成结构和生态网络变化,这可能与土壤理化性质恶化、土壤肥力下降密切相关,进而影响作物生长发育。     

Manganese as an ecological factor in salt marshes

The plant available manganese concentration (Mn²⁺) of salt-marsh sediments was compared to that of acidic and neutral soils. The mean soil-manganese concentration was higher in the top 1 cm of salt-marsh soil than in the neutral soil and comparable to that of the acidic soil (0–5 cm). A peak in the soil-manganese concentration in the upper marsh was observed one week after the spring tide but this effect was not evident in the lower marsh. Despite these differences, there was no correlation between mean manganese concentration and position on the marsh.The response to manganese of salt-marsh halophytes was studied by measuring growth and root elongation in a range of Mn²⁺ concentrations with and without sodium chloride. Although there was a differential response to manganese between salt-marsh species, manganese resistance was not related to position on the marsh. Most of the species investigated were tolerant of Mn²⁺ at concentrations higher than normally recommended for plant growth. Moreover a salt-marsh ecotype of Festuca rubra was found to have a higher manganese resistance than an inland ecotype of the same species.When sodium chloride was included in the growth medium, salt-marsh plants had a greatly increased resistance to manganese associated with a reduced uptake. This effect is reflected in the tissue-manganese concentration which was lower than in Deschampsia flexuosa although both groups of plants were exposed to a similar range of Mn²⁺ concentrations. It is concluded that sodium chloride markedly reduces the phytotoxicity of manganese in salt marshes.Nomenclature following Clapham, Tutin & Warburg (1968). Flora of the British Isles.The work was carried out while one of us (C. E. Singer) was in receipt of an SERC studentship, which is gratefully acknowledged.     

秦岭辛家山林区落叶松外生菌根真菌多样性

【目的】以秦岭辛家山林区落叶松为研究对象,观察鉴定与其共生的外生菌根真菌。【方法】通过野外调查结合形态学和分子生物学鉴定方法。【结果】鉴定出31种外生菌根真菌,分属2门4目11科11属,分别有毛革菌属(Tomentella)、丝盖伞属(Inocybe)、红菇属(Russula)、Amphinema、蜡蘑属(Laccaria)、蜡壳耳属(Sebacina)、鹅膏菌属(Amanita)、牛肝菌属(Boletus)、丝膜菌属(Cortinarius)、乳菇属(Lactarius)和硬皮马勃属(Scleroderma),丝盖伞属是优势类群。阳坡外生菌根真菌多样性高于阴坡。对菌根根际土与非根际土化学性质分析表明,pH值显著低于非根际,速效磷、速效钾含量显著高于非根际。对根际土化学性质与外生菌根侵染率相关性分析表明,落叶松外生菌根侵染率与土壤pH值呈显著正相关;与速效钾呈极显著正相关;与全氮、速效磷呈显著负相关。【结论】落叶松外生菌根真菌多样性丰富,且受坡向影响。外生菌根真菌可降低根际pH,提高根际有机质、全氮、速效磷、速效钾、水溶性钙和水溶性镁的含量。外生菌根侵染率受土壤pH值、全氮、速效磷、速效钾的影响。     

Associative nitrogenase activity by some Hawaiian grass roots

Summary Nitrogenase activity by the roots of some tropical grasses was detected by the acetylene reduction technique. In some cases particular plant species, evaluated at different times from different sites, displayed marked variations in nitrogenase activity.Acetylene reduction by root samples which had undergone preincubation under low O₂ displayed an increase of approximately 5-fold when compared to plant-containing soil cores. These increases in nitrogenase activity correspond to an increase in the number of nitrogen-fixing bacteria associated with the roots.Journal Series No. 2066 of the Hawaii Agricultural Experiment Station, Honolulu, Hawaii 96822Journal Series No. 2066 of the Hawaii Agricultural Experiment Station, Honolulu, Hawaii 96822     

Increased P diffusion as an explanation of increased p availability in flooded rice soils

Summary Phosphorus supply factors (capacity, kinetic, intensity, and diffusivity) and plant growth were the approaches used to assess P supply of flooded rice soils. Increases in the capacity, intensity, and kinetic factors, as measured by E-value, solution P concentration, and soil P release rate to a distilled water sink respectively, were unpronouced and infrequent upon water-saturation of ten soils. However, increases in the diffusitivity factor, as measured by ³²P diffusion coefficients, were at least ten-fold as soil moisture increased. The greatest increases in P diffusion occurred as soil moisture increased beyond one-third bar.Using a P fertilized soil or P treated powdered cellulose as the P source and a minus P nutrient solution to nourish a split root system with water and nutrients, data were obtained which suggested that P uptake and rice-shoot growth (indicators of P availability) increased with increasing moisture level. Phosphorus uptake and rice-shoot growth were greatst when the soil or P treated cellulose were water-saturated. These data indicate that increased soil P availability upon flooding can be attributed to an increase in the diffusivity factor.Paper Number 4532 of the Journal Series of the North Carolina Agricultural Experiment Station.Paper Number 4532 of the Journal Series of the North Carolina Agricultural Experiment Station.     

镉吸附细菌的分离及其对土壤镉的固定

[目的] 探究镉吸附细菌是否能够高效固定土壤有效镉（Cd）,为土壤有效Cd的微生物固定提供理论依据。[方法] 利用含Cd²⁺牛肉膏蛋白胨液体培养基对细菌进行Cd的耐受性测试筛选出镉抗性强的菌株;通过16S rRNA基因相似性及系统进化分析鉴定耐镉细菌,将菌细胞加入含CdCl₂溶液中进行Cd²⁺吸附效率测定;通过土培模拟实验,测定土壤pH、碱解氮、有效磷、速效钾、有机质、CEC、有效Cd及微生物数量来分析镉吸附细菌对镉污染土壤的影响。[结果] 从德阳鱼腥草根际土壤中分离获得的57株细菌对Cd²⁺表现出不同程度的抗性,并从中筛选出3株耐Cd优势细菌普罗威登斯菌属（Providencia）DY8、芽孢杆菌属（Bacillus）DY3和芽孢杆菌属（Bacillus）DY1-4。其对溶液中的Cd²⁺表现出较好的吸附作用,吸附效率随着Cd²⁺浓度升高而降低。DY8、DY3、DY1-4能使镉污染土壤中有效Cd含量分别降低72.11%、68.55%、62.32%,同时显著提高镉污染土壤中碱解氮、有效磷的含量。[结论] Cd污染农田土壤中含有丰富的耐Cd微生物资源,Cd吸附细菌能降低土壤中有效Cd的含量,且能有效改善土壤养分条件。     

香蕉假茎生物炭对根际土壤细菌丰度和群落结构的影响

【目的】将香蕉假茎生物炭施加到土壤,探讨香蕉假茎生物炭对香蕉根际土壤微生物的影响。【方法】以香蕉假茎生物炭(BPB)0、1%、2%、3%的质量比与土壤均匀混合。盆栽培养3个月后分离香蕉根际土壤。采用16S rRNA高通量测序技术对根际土壤细菌群落结构和丰度进行表征。【结果】提高BPB施用量可增加土壤有机质、有效钾、有效磷含量,提高土壤pH值,但降低有效氮浓度。在1%BPB样品中获得2278个OTUs,其显示细菌群落中的最大多样性。施加3%的BPB处理土壤,拟杆菌门、疣微菌门和厚壁菌门的相对丰度显著增加;放线菌门、酸杆菌门、芽单胞菌门明显减少。主成分分析发现,1%BPB和2%BPB处理的样本之间土壤细菌群落相似。【结论】施加不同比例BPB改变了根际土壤中细菌丰度和群落结构,且高比例添加改变更加明显。     

不同连作年限甜瓜种植土壤性质和微生物多样性

[背景]连作种植和化肥、农药过量施用导致设施甜瓜土壤质地恶化、病害严重,甜瓜产量和质量下降.[目的]明确甜瓜连作种植年限对土壤化学性质、土壤酶活性和微生物多样性的影响.[方法]以甜瓜种植1年、5年和10年的温室耕层土壤为研究对象,采用常规分析方法、土壤酶活测定试剂盒、稀释涂布平板法和Illumina MiSeq高通量测...