scholarly journals Assessing the role of fungal diversity in decomposition: A meta-analysis

2021 ◽  
Author(s):  
Sytske M. Drost ◽  
Annemieke van der Wal ◽  
Wietse de Boer ◽  
Paul. L.E. Bodelier
Keyword(s):  
Fungal Diversity ◽  
Selection Criteria ◽  
Field Experiments ◽  
Meta Analysis ◽  
C:N Ratio ◽  
Negative Relationship ◽  
Fungal Species ◽  
Control Treatment ◽  
Plant Materials ◽  
Diversity Gradient

AbstractFungi play an important role in carbon - and nutrient cycling. It is, however, unclear if diversity of fungi is essential to fulfill this role. With this meta-analysis, we aim to understand the relationship between fungal diversity and decomposition of plant materials (leaf litter and wood) in terrestrial and aquatic environments. The selection criteria for papers were the presence of a fungal diversity gradient and quantification of decomposition as mass loss. In total 40 papers met the selection criteria. We hypothesized that increase of fungal species will result in stronger decomposition, especially in species poor communities. Both artificial inoculated and naturally assembled fungal communities were included in the analysis in order to assess whether manipulated experiments are representative for field situations. We found a significant positive effect of increased fungal diversity on decomposition. However, in manipulated experiments this relationship was only positive when a control treatment of one fungus was compared with multispecies communities. This relationship became negative when comparisons of higher initial richness (at least two fungal species as “control”) were included. In contrast, under natural field conditions increased fungal diversity coincided with increased decomposition. This suggests that manipulated experiments are not representative for field situations. Possible reasons for this are discussed. Yet, both in manipulated and field experiments, environmental factors can influence diversity – decomposition relationships as indicated by a negative relationship of increasing C:N ratio on the effect of fungal diversity on decomposition. Overall, our results show that fungal diversity can have an important role in decomposition, but that design of experiments (manipulated or field) and quality of the plant material should be taken into account for interpretation of this diversity-functioning relationship.

scholarly journals Induced Resistance to Blackleg (Leptosphaeria maculans) Disease of Canola (Brassica napus) Caused by a Weakly Virulent Isolate of Leptosphaeria biglobosa

Plant Disease ◽  
2006 ◽  
Vol 90 (8) ◽  
pp. 1059-1064 ◽  
Author(s):  
Y. Chen ◽  
W. G. D. Fernando
Keyword(s):  
Brassica Napus ◽  
Field Experiments ◽  
Leptosphaeria Maculans ◽  
Fungal Species ◽  
Control Treatment ◽  
Water Control ◽  
Pathogenicity Group ◽  
Weakly Virulent ◽  
Leptosphaeria Biglobosa ◽  
Highly Virulent

Blackleg of canola is a disease complex of at least two fungal species: Leptosphaeria maculans and L. biglobosa. Isolates of L. biglobosa typically are weakly virulent or avirulent and are assigned to pathogenicity group 1 (PG-1). Isolates of L. maculans are highly virulent and encompass pathogenicity groups PG-2, PG-3, and PG-4. In greenhouse tests, percent lesion/leaf area (PLLA) on cotyledons of two Brassica napus cultivars, Westar and Invigor 2153, was smaller when L. biglobosa (PG-1) was either pre- or co-inoculated at 0, 12, 24, and 48 h with virulent isolates of L. maculans in PG-2, PG-3, and PG-4. On six-leaf-stage plants of Westar, the PLLA declined significantly compared with the control when the lower leaves were treated with either PG-1 or salicylic acid, then challenged with a PG-2 isolate 24 h later. In addition, the activity of four enzymes (chitinase, β-1,3-glucanase, peroxidase, and phenylalanine ammonia lyase) was greatly enhanced at 48 and 72 h when cotyledons of Westar were inoculated first with PG-1 followed by PG-2 24 h later, compared with a water control treatment. Field experiments conducted in 2003 and 2004 showed decreased blackleg severity in plants inoculated with PG-1 alone or prior to PG-2 compared with plants inoculated with PG-2 alone or prior to PG-1.

A Meta-Analytic Review of the Relationship Between Learning Organization and Organizational Performance and Employee Attitudes: Using the Dimensions of Learning Organization Questionnaire

2021 ◽  
pp. 153448432098736
Author(s):  
Boreum Ju ◽  
Yunsoo Lee ◽  
Sunyoung Park ◽  
Seung Won Yoon
Keyword(s):  
Organizational Performance ◽  
National Culture ◽  
Learning Organization ◽  
Meta Analysis ◽  
Negative Relationship ◽  
Employee Attitudes ◽  
Future Research ◽  
Analytic Review ◽  
Dimensions Of Learning ◽  
The Relationship

The purpose of this meta-analysis study is to examine the correlations between the Dimensions of Learning Organization Questionnaire (DLOQ) and frequently examined outcomes including organizational performance and employee attitudes. Positive relationships were found between the DLOQ and organizational performance (e.g., financial, knowledge, and innovative performance) and employee attitudes (e.g., organizational commitment and job satisfaction) and the sub-dimensions (e.g., affective, continuance, and normative commitment), with a notable exception of a negative relationship between the DLOQ and turnover. Because the DLOQ has been used in many countries over the years, this study also examined the influence of national culture on the outcomes. Power distance moderated the relationship between the learning organization and overall organizational performance. Our meta-analytic review makes substantive contributions to the literature on the learning organization concept and the study of national culture as a significant moderator. Implications of these findings and suggestions for future research are discussed.

scholarly journals Profiling Dust Mass Concentration in Northwest China Using a Joint Lidar and Sun-photometer Setting

2021 ◽  
Vol 13 (6) ◽  
pp. 1099
Author(s):  
Tianhe Wang ◽  
Ying Han ◽  
Wenli Hua ◽  
Jingyi Tang ◽  
Jianping Huang ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Field Experiments ◽  
Negative Relationship ◽  
Northwest China ◽  
Dust Particles ◽  
Mass Loading ◽  
Average Mass ◽  
Dust Mass ◽  
Dust Loading ◽  
Sun Photometer

The satellite-based estimation of the dust mass concentration (DMC) is essential for accurately evaluating the global biogeochemical cycle of the dust aerosols. As for the uncertainties in estimating DMC caused by mixing dust and pollutants and assuming a fixed value for the mass extinction efficiency (MEE), a classic lidar-photometer method is employed to identify and separate the dust from pollutants, obtain the dust MEE, and evaluate the effect of the above uncertainties, during five dust field experiments in Northwest China. Our results show that this method is effective for continental aerosol mixtures consisting of dust and pollutants. It is also seen that the dust loading mainly occurred in the free troposphere (< 6 km), with the average mass loading of 905 ± 635 µg m−2 trapped in the planetary boundary layer. The dust MEE ranges from 0.30 to 0.60 m2 g−1 and has a significantly negative relationship with the size of dust particles. With the assumption of the dust MEE of 0.37 (0.60) m2 g−1, the DMC is shown to be overestimated (underestimated) by 20–40% (15–30%). In other words, our results suggest that the change of MEE with the size of dust particles should be considered in the estimation of DMC.

scholarly journals Microbial Communities, Metabolites, Fermentation Quality and Aerobic Stability of Whole-Plant Corn Silage Collected from Family Farms in Desert Steppe of North China

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 784
Author(s):  
Chao Wang ◽  
Lin Sun ◽  
Haiwen Xu ◽  
Na Na ◽  
Guomei Yin ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Bacterial Diversity ◽  
Fungal Diversity ◽  
North China ◽  
Bacterial Species ◽  
Fungal Species ◽  
Family Farms ◽  
Aerobic Stability ◽  
Whole Plant ◽  
Lactobacillus Kefiri

Whole-plant corn silages on family farms were sampled in Erdos (S1), Baotou (S2), Ulanqab (S3), and Hohhot (S4) in North China, after 300 d of ensiling. The microbial communities, metabolites, and aerobic stability were assessed. Lactobacillusbuchneri, Acinetobacter johnsonii, and unclassified Novosphingobium were present at greater abundances than others in S2 with greater bacterial diversity and metabolites. Lactobacillus buchneri, Lactobacillus parafarraginis, Lactobacillus kefiri, and unclassified Lactobacillus accounted for 84.5%, and 88.2%, and 98.3% of bacteria in S1, S3, and S4, respectively. The aerobic stability and fungal diversity were greater in S1 and S4 with greater abundances of unclassified Kazachstania, Kazachstania bulderi, Candida xylopsoci, unclassified Cladosporium, Rhizopus microspores, and Candida glabrata than other fungi. The abundances of unclassified Kazachstania in S2 and K. bulderi in S3 were 96.2% and 93.6%, respectively. The main bacterial species in S2 were L. buchneri, A. johnsonii, and unclassified Novosphingobium; Lactobacillus sp. dominated bacterial communities in S1, S3, and S4. The main fungal species in S1 and S4 were unclassified Kazachstania, K. bulderi, C. xylopsoci, unclassified Cladosporium, R. microspores, and C. glabrata; Kazachstania sp. dominated fungal communities in S2 and S3. The high bacterial diversity aided the accumulation of metabolites, and the broad fungal diversity improved the aerobic stability.

Inverse Relationship Between Serum Bilirubin and Atherosclerosis in Men: A Meta-Analysis of Published Studies

2003 ◽  
Vol 228 (5) ◽  
pp. 568-571 ◽  
Author(s):  
Ladislav Novotný ◽  
Libor Vítek
Keyword(s):  
Inverse Relationship ◽  
Serum Bilirubin ◽  
Linear Trend ◽  
Meta Analysis ◽  
Negative Relationship ◽  
Epidemiological Studies ◽  
Atherosclerotic Disease ◽  
Categorical Variables ◽  
History Of ◽  
Stratified Analysis

Bilirubin, a major intravascular product of heme catabolism, is a potent antioxidant compound. Numerous studies have been published showing the relationship between serum bilirubin levels and atherosclerosis. In the present investigation all the epidemiological studies available on the effect of serum bilirubin levels and atherosclerotic disease were analyzed. Studies on the epidemiology of atherosclerotic diseases in relation to serum bilirubin levels were searched in the MEDLINE database. Selected studies were subdivided according to serum bilirubin levels and severity of atherosclerotic disease. Because of the limited number of females involved in the studies, only males were included into meta-analysis. Associations for ordered categorical variables (bilirubin and natural history of graded atherosclerosis) were assessed to find correlation and linear trend between analyzed variables. A stratified analysis was conducted to compare risks of clinical outcomes. Eleven relevant studies were used for analysis. A close negative relationship was found between serum bilirubin levels and severity of atherosclerosis (Spearman rank coefficient r = −0.31, P < 0.0001). The linear trend was confirmed in analysis of proportions with x2 values for both disease conditions to be very significant ( P < 0.0001). Unambiguous inverse relationship between serum bilirubin levels and atherosclerosis was demonstrated in this preliminary meta-analytic study. These results indicate the importance of hem oxygenase-related products in the prevention of oxidative stress-mediated diseases.

Factors affecting the yield of winter cereals in crop margins

2000 ◽  
Vol 135 (4) ◽  
pp. 335-346 ◽  
Author(s):  
A. WILCOX ◽  
N. H. PERRY ◽  
N. D. BOATMAN ◽  
K. CHANEY
Keyword(s):  
Soil Compaction ◽  
Dry Matter ◽  
Field Experiments ◽  
Polynomial Regression ◽  
Negative Relationship ◽  
Fertilizer Application ◽  
Winter Cereal ◽  
Edge Field ◽  
Winter Cereals ◽  
Non Linear

Yields of arable crops are commonly lower on the crop margins or headlands, but the nature of the relationship between yield and distance from the crop edge has not been clearly defined, nor have the reasons for lower marginal yields. Surveys of 40 winter wheat headlands were carried out in 2 years to determine how yield changed with distance, and what factors might influence this relationship. Two field experiments were also conducted over 3 years in winter cereal headlands, in which the effect of distance was measured under conservation headland and conventional (fully sprayed) management.Yields in the headland surveys varied from 0·8 to 10·2 t/ha. An inverse polynomial regression model was fitted to yield and weed data. Best fits were obtained by using separate parameters for each site. Adjusting yields to take account of weed dry matter improved the non-linear fit between yield and distance from crop edge. Field experiments provided similar results but the non-linear relationship was not as apparent.There was a negative relationship between soil compaction, as measured by a cone penetrometer, and yield in one field experiment, where soil density values were relatively constant. No relationship was found between pattern of nitrogen fertilizer application and yield. Conservation headland management resulted in lower yield at one experimental site, especially in the third year, but not at the other site. Where yields were affected, weed dry matter was higher in conservation headland plots than in fully sprayed plots.Although greater weed competition appears to account for at least part of the observed yield reductions on headlands, the role of other factors, particularly soil compaction, needs further study. Increased weed infestation may be an indirect result of reduced crop competition caused by other adverse conditions.

scholarly journals PSII-17 Program Chair Poster Pick: Effect of ruminal protozoa on methane emissions in ruminants – a meta-analysis

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 397-398
Author(s):  
Xiaoxia Dai ◽  
Kenneth Kalscheur ◽  
Pekka Huhtanen ◽  
Antonio Faciola
Keyword(s):  
Dairy Cows ◽  
Meta Analysis ◽  
Random Effect ◽  
Negative Relationship ◽  
Small Ruminants ◽  
Methane Emissions ◽  
Mitigation Strategies ◽  
Positive Relationships ◽  
Ruminal Fermentation ◽  
The Relationship

Abstract The effects of ruminal protozoa (RP) concentration on methane emissions from ruminants were evaluated in a meta-analysis using 67 publications reporting data from 85 in vivo experiments. Experiments included in the database reported methane emissions (g/kg DMI) and RP (log10 cells/mL) from the same group of animals. Quantitative data including diet chemical composition, ruminal fermentation, total tract digestibility, and milk production; and qualitative information including methane mitigation strategies, animal type, and methane measurement methods were also collected. The studies were conducted in dairy cows (51%), beef steers (32%) and small ruminants (32%). 70% of the studies reported a reduction in methane emissions. Supplemental lipids reduced methane emissions 95% of the time. The relationship between methane emissions and RP concentration was evaluated as a random coefficient model with the experiment as a random effect and weighted by the inverse pooled SEM squared, including the possibility of covariance between the slope and the intercept. A quadratic effect of RP concentration on methane emissions was detected: CH4= -28.8 + 12.2 × RP-0.64 × RP2. To detect potential interfering factors in the relationship, the influence of several qualitative and quantitative factors were separately tested. Acetate, butyrate, and isobutyrate molar proportions had positive relationships with methane emissions and influenced the relationship between RP concentration and methane emissions, where the presence of ruminal fermentation variables reduced the effects of RP concentration in methane emissions. Total tract digestibility of DM, OM, and CP had negative relationships while NDF digestibility had a positive relationship with methane emissions; however, they only changed the magnitude of intercept and slope of RP and RP2 for the relationship. For dairy cows, milk fat and protein concentrations had positive relationships and milk yield had a negative relationship with methane emissions and changed the magnitude of intercept and slope of RP and RP2 for the relationship.

scholarly journals Board Attributes and Corporate Social Responsibility Disclosure: A Meta-Analysis

2018 ◽  
Vol 10 (12) ◽  
pp. 4808 ◽  
Author(s):  
Jaime Guerrero-Villegas ◽  
Leticia Pérez-Calero ◽  
José Hurtado-González ◽  
Pilar Giráldez-Puig
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Meta Analysis ◽  
Negative Relationship ◽  
Board Independence ◽  
Board Size ◽  
Ceo Duality ◽  
Capital Costs ◽  
Corporate Social Responsibility Disclosure ◽  
Corporate Social

Many studies have examined the relationships between board attributes (board independence, CEO duality, board size, and women on boards) and corporate social responsibility disclosure (CSRD) as a means to improve a firm’s reputation. This research was performed in various international settings and uneven outcomes were obtained. We therefore meta-analyzed 88 studies to summarize scattered evidence and found that CEO duality had a significantly negative relationship with CSRD, while board independence, board size and women representation had a significantly positive relationship with CSRD. These relationships were more significant in countries with low levels of commitment to sustainable goals. Thus, our study revealed differences in the relationship between board attributes and CSRD, and that these differences were conditioned by the institutional contexts in which firms operate. Our research has practical implications for practitioners and policy makers alike as we offer guidelines on the most suitable corporate governance mechanisms to achieve lower capital costs and better access to finance.

scholarly journals Different Amplicon Targets for Sequencing-Based Studies of Fungal Diversity

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Francesca De Filippis ◽  
Manolo Laiola ◽  
Giuseppe Blaiotta ◽  
Danilo Ercolini
Keyword(s):  
Microbial Ecology ◽  
High Throughput ◽  
Biological Samples ◽  
Fungal Diversity ◽  
High Throughput Sequencing ◽  
Amplicon Sequencing ◽  
Fungal Species ◽  
Fungal Communities ◽  
Its2 Region ◽  
Mock Community

ABSTRACT Target-gene amplicon sequencing is the most exploited high-throughput sequencing application in microbial ecology. The targets are taxonomically relevant genes, with 16S rRNA being the gold standard for bacteria. As for fungi, the most commonly used target is the internal transcribed spacer (ITS). However, the uneven ITS length among species may promote preferential amplification and sequencing and incorrect estimation of their abundance. Therefore, the use of different targets is desirable. We evaluated the use of three different target amplicons for the characterization of fungal diversity. After an in silico primer evaluation, we compared three amplicons (the ITS1-ITS2 region [ITS1-2], 18S ribosomal small subunit RNA, and the D1/D2 domain of the 26S ribosomal large subunit RNA), using biological samples and a mock community of common fungal species. All three targets allowed for accurate identification of the species present. Nevertheless, high heterogeneity in ITS1-2 length was found, and this caused an overestimation of the abundance of species with a shorter ITS, while both 18S and 26S amplicons allowed for more reliable quantification. We demonstrated that ITS1-2 amplicon sequencing, although widely used, may lead to an incorrect evaluation of fungal communities, and efforts should be made to promote the use of different targets in sequencing-based microbial ecology studies. IMPORTANCE Amplicon-sequencing approaches for fungi may rely on different targets affecting the diversity and abundance of the fungal species. An increasing number of studies will address fungal diversity by high-throughput amplicon sequencing. The description of the communities must be accurate and reliable in order to draw useful insights and to address both ecological and biological questions. By analyzing a mock community and several biological samples, we demonstrate that using different amplicon targets may change the results of fungal microbiota analysis, and we highlight how a careful choice of the target is fundamental for a thorough description of the fungal communities.

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