Is PLOS ONE Attracting Highly Cited Papers in the Food Sciences? Comparing Authors' Most Cited Work to Their PLOS ONE Articles Published 2006–2016

Since 2007, the Open Access journal PLOS ONE has published 194,622 expert-reviewed scientific papers, including 85 related to the human food sciences such as food safety, general food science, and nutrition. Seventy-five of their corresponding authors had previously published. Their most cited articles in other journals were identified and citation counts compared against those earned by their PLOS ONE papers. No PLOS ONE food sciences paper has yet been cited more than an author's best effort in the field in other journals. More than half (38) of the 75 PLOS ONE papers studied remain uncited even by their own authors.     

近红外反射光谱分析在土壤肥料学的应用及发展方向

近红外反射光谱分析是一种"巨人"分析法,在土壤肥料及植物营养科学具有广阔的应用前景。对近红外反射光谱分析在土壤肥料及植物营养学科中的应用,存在问题,及其在土壤肥料及植物营养学科领域的发展方向进行了评述。     

新疆阜康荒漠植被指数特征和时空过程分析

研究天山北坡典型荒漠区草地植被覆盖变化,对于荒漠区草畜平衡及畜牧业可持续发展具有重要现实意义。采用1990,1999和2008年同时相TM/ETM+遥感影像,经辐射校正和几何校正后,基于荒漠植被指数特征和垂直地带性特征,进行了专家知识决策树分类,研究了阜康市典型荒漠草地、农田等地物近20年间的归一化植被指数(NDVI)和面积变化特征。结果表明,1) 经辐射校正后的NDVI与实际地物情况更接近,大致呈高山草甸>农田>温性草甸>平原荒漠>山前荒漠的规律;2)近20年间农区面积大量占用平原荒漠草地和山前荒漠,新增农田面积296.3 km²,是1990年耕地总面积的1.54倍;3)高山冰盖消融随即转变成为高山草甸类型的趋势明显,20年间减少冰雪区74.7 km²,是1990年冰雪区总面积的0.345倍,这也印证了近20年来全球变暖的说法。     

The impact of clonality on an endangered tree (Elaeocarpus williamsianus) in a fragmented rainforest

The occurrence and distribution of clonality in the endangered rainforest tree Elaeocarpus williamsianus (Elaeocarpaceae) was investigated using SSR and RAPD analyses for 170 apparent individual trees found across seven sites. The results obtained with the two molecular techniques were in complete agreement in showing that single clones are present in most of the E. williamsianus sites with two genets occurring at the largest and most adequately protected site. In addition, seed production, viability and germinability were determined for four of these populations. Fruit were produced in all four populations tested although sterile fruit were very common. Only two E. williamsianus trees representing different genets within the same site produced viable seed. The overall genetic diversity within E. williamsianus is much lower than expected and thus the potential for sexual reproduction has been significantly diminished. It is concluded that habitat fragmentation removed an existing balance between vegetative and sexual reproduction in this species. Such findings have added urgency to the management of this species which could include a reintroduction program incorporating the collation of all clones within selected sites.     

依据传统土壤数据应用数字土壤制图法对香港山地地区土壤建立土纲信息

Based on legacy soil data from a soil survey conducted recently in the traditional manner in Hong Kong of China, a digital soil mapping method was applied to produce soil order information for mountain areas of Hong Kong. Two modeling methods (decision tree analysis and linear discriminant analysis) were used, and their applications were compared. Much more eflort was put on selecting soil covariates for modeling. First, analysis of variance (ANOVA) was used to test the variance of terrain attributes between soil orders. Then, a stepwise procedure was used to select soil covariates for linear discriminant analysis, and a backward removing procedure was developed to select soil covariates for tree modeling. At the same time, ANOVA results, as well as our knowledge and experience on soil mapping, were also taken into account for selecting soil covariates for tree modeling. Two linear discriminant models and four tree models were established finally, and their prediction performances were validated using a multiple jackknifing approach. Results showed that the discriminant model built on ANOVA results performed best, followed by the discriminant model built by stepwise, the tree model built by the backward removing procedure, the tree model built according to knowledge and experience on soil mapping, and the tree model built automatically. The results highlighted the importance of selecting soil covariates in modeling for soil mapping, and suggested the usefulness of methods used in this study for selecting soil covariates. The best discriminant model was finally selected to map soil orders for this area, and validation results showed that thus produced soil order map had a high accuracy.     

Pb胁迫对藿香蓟（Ageratum conyzoides）营养积累与分配的影响

为了解Pb胁迫对地被植物藿香蓟（Ageratum conyzoides）生长特性的影响,采用盆栽控制试验,研究了不同Pb浓度（0、250、500、750、1000、1250、1500mg·kg-1）胁迫处理下霍香蓟植株生物生产量、生物量分配格局及N、P、K、Mg积累和分配特征。结果表明,低浓度Pb胁迫处理明显增加了藿香蓟的生物量、根茎叶中N、P、K、Mg含量及养分积累,改变了养分在植物体内的分配格局,但高浓度Pb胁迫处理明显抑制了植物生长,降低了根茎叶中P、K的含量和积累量。这说明藿香蓟能在一定程度上适应Pb污染土壤环境,可用于轻度Pb污染区域的园林绿化。     

Phosphorus nutrition of white rose potato in relation to growth and minerals of leaf and root tissues

Abstract

White Rose potato plants (Solanum tuberosum, L.) were grown outdoors, without tuber formation, in a modified Hoagland's nutrient solution with 9 treatments of KH₂PO₄ ranging from 0 to 4.0 mmoles per liter. Deficiency symptoms ranged from very severe to none at harvest after 27 days of growth. Growth of the potato plants increased with increased P supply and was associated with an increased P content of the plant tissues. The critical H₂PO₄‐P concentration at a 10% reduction of top growth, based on a second leaf analysis, was about 1,000 ppm for the petiole and terminal bladelet and about 1,200 ppm for the lateral bladelet, dry weight basis.

Phosphorus nutrition had only a slight effect on the K, Na, Mg and NO₃‐N concentrations of the root tissues but Ca increased as phosphate increased which suggests a calcium phosphate precipitation. Phosphorus stress lowered the K, Na, Ca, Mg and NO₃‐N concentrations of the petiole tissues of the recently matured leaf which suggests that P increases salt accumulation. Phosphorus nutrition had only a slight effect on the concentrations of K, Na, Mg and Ca of the blade tissues of the recently matured leaf but NO₃‐N increased greatly with P supply.     

Lime,molybdenum, and cultivar effects on molybdenum deficiency of poinsettia

Poinsettia (Euphorbia pulcherrima Willd. ex Klotz) cultivars ‘Annette Hegg Brilliant Diamond’ (AH), ‘Gutbier V‐14 Glory’ (GG), and ‘Eckespoint C‐1 Red’ (ER) were grown in a peat‐perlite potting medium to study lime and Mo effects on the occurrence of Mo deficiency. Two rates of dolomitic limestone, 0 and 3 kg/m³of growing medium, and weekly applications of micronutrient solutions containing 0.0 or 1.0 ppm Mo were made in factorial combination. Lime, Mo, or both prevented Mo deficiency symptoms in all cultivars. Without both lime and Mo, Mo deficiency symptoms appeared on AH and GG, but not on ER. Lime and/or Mo reduced NO₃‐N content, increased Mo content and increased nitrate reductase enzyme activity (NRA) in the upper recently matured leaves of all cultivars. Lime and Mo interacted to affect these parameters in all cultivars. Comparing the three cultivars without both lime and Mo, NO‐‐N content was lowest and NRA highest in ER. However, the Mo content of ER leaves was equal to or less than that of AG and GG which showed Mo deficiency symptoms.     

不同施肥措施对玉米根际土壤微生物数量及养分含量的影响

通过田间试验,研究了不同施肥措施对根际土壤微生物数量及养分含量的影响。结果表明:(1)施肥显著提高了根际土壤微生物数量。在玉米生育期内土壤细菌和放线菌数量平均数量表现为MNP(有机肥+N+P)>M(有机肥)>NP(N+P)>CK(对照),与CK相比,MNP、M和NP处理细菌数量分别提高了302.82%、183.96%和136.23%,而放线菌数量则分别提高了93.97%%、62.64%和54.28%。土壤真菌平均数量表现为MNP>NP>CK>M,其中MNP和NP分别比CK提高了33.74%和29.08,而M则比CK降低了8.39%。土壤好气性固氮细菌平均数量表现为MNP>NP>M>CK,MNP、M和NP分别比CK提高了55.46%、24.63%和40.87%。(2)在玉米收获期土壤有机质和各营养指标含量均比播种期降低,不同施肥处理土壤有机质含量在播种期和收获期均表现为M>MNP>CK>NP,而土壤全氮、全磷、全钾、碱解氮和速效磷含量在播种期表现为MNP>NP>M>CK,在收获期表现则不尽一致。(3)土壤细菌、放线菌和固氮菌数量均与土壤全氮、全磷和碱解氮含量之间有显著正相关关系(P<0.05),土壤真菌数量与土壤有机质及各养分含量之间相关性较差。     

新时代土壤化学前沿进展与展望

土壤化学是重要的土壤学基础分支学科。在回顾了土壤化学发展历程的基础上,梳理了土壤化学的四个前沿交叉方向,并展望了土壤化学与其他相关学科的交叉发展趋势,以期寻求新的学科增长点。土壤化学经历了从恒电荷到可变电荷土壤学说演变,我国在土壤电化学、根际土壤化学、土壤化学-物理-微生物界面反应等方向逐步领跑。新时代中国已经发展成为国际土壤化学的研究中心之一,尤其在土壤化学与微生物学、地球化学、矿物学、环境化学等交叉领域取得了突破性发展。同时,发展并运用同步辐射、微流控联用光谱能谱、高分辨显微镜、光谱电化学等实时、原位、高精度研究方法,推动土壤化学研究取得了长足的进步。新时代的土壤化学具有三个重要发展趋势,首先系统揭示地球表层系统中物质循环与能量交换的土壤化学机制,实现"0到1"的土壤化学原创性成果的突破;其次需要综合运用地球表层系统理论,从多界面、多要素、多过程的"三多"交互耦合;再次,需要加强与地球宜居性这一人类重大命题的交叉融合,为生态文明建设、土壤污染防治攻坚战、全球变化等国家重大需求提供理论支持。