scholarly journals Soil microbes weaken the positive effect of an aquatic-terrestrial subsidy on plant performance

2020 ◽  
Author(s):  
Alejandra B Garcia ◽  
Hannah Locke ◽  
Kerri M Crawford
Keyword(s):  
Soil Microbes ◽  
Lake Michigan ◽  
Plant Biomass ◽  
Plant Productivity ◽  
Plant Performance ◽  
Nutrient Inputs ◽  
Positive Effects ◽  
Terrestrial Subsidy ◽  
The Impact ◽  
Terrestrial Subsidies

Abstract Aims Linkages formed through aquatic-terrestrial subsidies can play an important role in structuring communities and mediating ecosystem functions. Aquatic-terrestrial subsidies may be especially important in nutrient-poor ecosystems, such as the freshwater sand dunes surrounding Lake Michigan. Adult midges emerge from Lake Michigan in the spring, swarm to mate, and die. Their carcasses form mounds at the base of plants, where they may increase plant productivity through their nutrient inputs. However, the effect of aquatic-terrestrial subsidies on plant productivity could depend on other biotic interactions. In particular, soil microbes might play a key role in facilitating the conversion of nutrients to plant-available forms or competing for the nutrients by plants. Methods In a greenhouse experiment, we tested how carcasses from lake-emergent midges (Chironomidae) and soil microbes independently and interactively influenced the performance of a common dune grass, Calamovilfa longifolia. To determine whether midges influenced abiotic soil properties, we measured how midge additions influenced soil nutrients and soil moisture. Important findings Midges greatly increased plant biomass, while soil microbes influenced the magnitude of this effect. In the absence of soil microbes plant biomass was 7 times greater with midges than without midges. However, in the presence of soil microbes, plant biomass was only 3 times greater. The effect of midges might be driven by their nutrient inputs into the soil, as midges contained 100 times more N, 10 times more P, and 150 times more K than dune soils did. Our results suggest that soil microbes may be competing with plants for these nutrients. In sum, we found that midges can be an important aquatic-terrestrial subsidy that produces strong, positive effects on plant productivity along the shorelines of Lake Michigan, but that the impact of aquatic-terrestrial subsidies must be considered within the context of the complex interactions that take place within ecological communities.

scholarly journals Response of Barley Plants to Drought Might Be Associated with the Recruiting of Soil-Borne Endophytes

2020 ◽  
Vol 8 (9) ◽  
pp. 1414
Author(s):  
Luhua Yang ◽  
Peter Schröder ◽  
Gisle Vestergaard ◽  
Michael Schloter ◽  
Viviane Radl
Keyword(s):  
Drought Stress ◽  
Bacterial Communities ◽  
Soil Microbes ◽  
Plant Biomass ◽  
Management Strategies ◽  
Plant Performance ◽  
Soil Microbiome ◽  
Bacterial Endophytes ◽  
Natural Conditions

Mechanisms used by plants to respond to water limitation have been extensively studied. However, even though the inoculation of beneficial microbes has been shown to improve plant performance under drought stress, the inherent role of soil microbes on plant response has been less considered. In the present work, we assessed the importance of the soil microbiome for the growth of barley plants under drought stress. Plant growth was not significantly affected by the disturbance of the soil microbiome under regular watering. However, after drought stress, we observed a significant reduction in plant biomass, particularly of the root system. Plants grown in the soil with disturbed microbiome were significantly more affected by drought and did not recover two weeks after re-watering. These effects were accompanied by changes in the composition of endophytic fungal and bacterial communities. Under natural conditions, soil-derived plant endophytes were major colonizers of plant roots, such as Glycomyces and Fusarium, whereas, for plants grown in the soil with disturbed microbiome seed-born bacterial endophytes, e.g., Pantoea, Erwinia, and unclassified Pseudomonaceae and fungal genera normally associated with pathogenesis, such as Gibberella and Gaeumannomyces were observed. Therefore, the role of the composition of the indigenous soil microbiota should be considered in future approaches to develop management strategies to make plants more resistant towards abiotic stress, such as drought.

scholarly journals Expression of cyanobacterial genes enhanced CO2 assimilation and biomass production in transgenic Arabidopsis thaliana

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11860
Author(s):  
Anum Zeb Abbasi ◽  
Misbah Bilal ◽  
Ghazal Khurshid ◽  
Charilaos Yiotis ◽  
Iftikhar Zeb ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transgenic Plants ◽  
Plant Biomass ◽  
Electron Flow ◽  
Single Gene ◽  
Soluble Sugars ◽  
Plant Productivity ◽  
Transcriptomic Analysis ◽  
Plant Performance ◽  
Cyanobacterial Genes

Background Photosynthesis is a key process in plants that is compromised by the oxygenase activity of Rubisco, which leads to the production of toxic compound phosphoglycolate that is catabolized by photorespiratory pathway. Transformation of plants with photorespiratory bypasses have been shown to reduce photorespiration and enhance plant biomass. Interestingly, engineering of a single gene from such photorespiratory bypasses has also improved photosynthesis and plant productivity. Although single gene transformations may not completely reduce photorespiration, increases in plant biomass accumulation have still been observed indicating an alternative role in regulating different metabolic processes. Therefore, the current study was aimed at evaluating the underlying mechanism (s) associated with the effects of introducing a single cyanobacterial glycolate decarboxylation pathway gene on photosynthesis and plant performance. Methods Transgenic Arabidopsis thaliana plants (GD, HD, OX) expressing independently cyanobacterial decarboxylation pathway genes i.e., glycolate dehydrogenase, hydroxyacid dehydrogenase, and oxalate decarboxylase, respectively, were utilized. Photosynthetic, fluorescence related, and growth parameters were analyzed. Additionally, transcriptomic analysis of GD transgenic plants was also performed. Results The GD plants exhibited a significant increase (16%) in net photosynthesis rate while both HD and OX plants showed a non-significant (11%) increase as compared to wild type plants (WT). The stomatal conductance was significantly higher (24%) in GD and HD plants than the WT plants. The quantum efficiencies of photosystem II, carbon dioxide assimilation and the chlorophyll fluorescence-based photosynthetic electron transport rate were also higher than WT plants. The OX plants displayed significant reductions in the rate of photorespiration relative to gross photosynthesis and increase in the ratio of the photosynthetic electron flow attributable to carboxylation reactions over that attributable to oxygenation reactions. GD, HD and OX plants accumulated significantly higher biomass and seed weight. Soluble sugars were significantly increased in GD and HD plants, while the starch levels were higher in all transgenic plants. The transcriptomic analysis of GD plants revealed 650 up-regulated genes mainly related to photosynthesis, photorespiratory pathway, sucrose metabolism, chlorophyll biosynthesis and glutathione metabolism. Conclusion This study revealed the potential of introduced cyanobacterial pathway genes to enhance photosynthetic and growth-related parameters. The upregulation of genes related to different pathways provided evidence of the underlying mechanisms involved particularly in GD plants. However, transcriptomic profiling of HD and OX plants can further help to identify other potential mechanisms involved in improved plant productivity.

scholarly journals Phosphorus and Nitrogen Modulate Plant Performance in Shrubby Legumes from the Iberian Peninsula

Plants ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 334 ◽  
Author(s):  
María Pérez-Fernández ◽  
Ángel Míguez-Montero ◽  
Alexandre Valentine
Keyword(s):  
Plant Biomass ◽  
Plant Performance ◽  
Physiological Basis ◽  
Retama Sphaerocarpa ◽  
Resistant Species ◽  
In The Wild ◽  
Use Efficiency ◽  
Effects Of Drought ◽  
Inoculation Treatment ◽  
The Impact

We investigated the impact of phosphorus nutrition on plant growth and biological nitrogen fixation in four leguminous plants in the Tribe Genistea. The main objective of the study was to analyze Phosphorus and Nitrogen use efficiency under drought. We also tested for the effects of rhizobial inoculation on plant performance. Plants inoculated with Rhizobium strains isolated from plants of the four species growing in the wild were cropped under controlled conditions in soils with either low P (5 µM) or high P (500 µM). The experiment was replicated in the presence and absence of plant irrigation to test for the effects of drought stress of inoculated and non-inoculated plants under the two P levels of fertilization. Low-P treatments increased nodule production while plant biomass and shoot and root P and N contents where maximum at high P. Low P (5 µM) in the growing media, resulted in greater N accumulated in plants, coupled with greater phosphorus and nitrogen uptake efficiencies. Drought reduced the relative growth rate over two orders of magnitude or more, depending on the combination of plant species and treatment. Genista cinerea had the lowest tolerance to water scarcity, whereas Genista florida and Retama sphaerocarpa were the most resistant species to drought. Drought resistance was enhanced in the inoculated plants. In the four species, and particularly in Echinospartum barnadesii, the inoculation treatment clearly triggered N use efficiency, whereas P use efficiency was greater in the non-inoculated irrigated plants. Nodulation significantly increased in plants in the low P treatments, where plants showed a greater demand for N. The physiological basis for the four species being able to maintain their growth at low P levels and to respond to the greater P supply, is through balanced acquisition of P and N to meet the plants’ nutritional needs.

scholarly journals Beneficial Soil Microbes Negatively Affect Spider Mites and Aphids in Pepper

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1831
Author(s):  
Maria L. Pappas ◽  
Konstantinos Samaras ◽  
Ioannis Koufakis ◽  
George D. Broufas
Keyword(s):  
Plant Growth ◽  
Soil Microbes ◽  
Plant Biomass ◽  
Growth Parameters ◽  
Bacterial Species ◽  
Defense Responses ◽  
Spider Mites ◽  
Root Weight ◽  
Microbial Inoculation ◽  
The Impact

Beneficial soil microbes have long been recognized for their ability to improve plant growth, to antagonize pathogens and to prime plants against biotic stressors. Nevertheless, their ability to enhance plant resistance against arthropod pests remains largely unexplored, especially in crop plants such as pepper. Herein, we assessed the effects of several fungal and bacterial species/strains applied in the soil on the performance of key pests of pepper plants. Specifically, we recorded the impact of pepper inoculation with commercial strains of beneficial bacteria (Bacillus amyloliquefaciens and Pseudomonas spp.) as well as fungi (Trichoderma spp. and Cordyceps fumosorosea) on the population growth of the green peach aphid, Myzus persicae, and the two-spotted spider mite, Tetranychus urticae. Furthermore, we recorded the effects of microbial inoculation on plant growth parameters, such as stem and root weight. We found that both pests can be negatively affected by microbial inoculation: spider mites laid up to 40% fewer eggs, and the number of aphids were up to 50% less on pepper-inoculated plants, depending on the microbe. We also recorded a variation among the tested microbes in their impact on herbivore performance, but no significant effects were found on plant biomass. Our results add to the growing literature that beneficial soil microbes may be capable of exerting biocontrol capabilities against aboveground herbivorous pests possibly, among other means, via the elicitation of plant defense responses.

scholarly journals Low functional redundancy among mammalian browsers in regulating an encroaching shrub ( Solanum campylacanthum ) in African savannah

2014 ◽  
Vol 281 (1785) ◽  
pp. 20140390 ◽  
Author(s):  
Robert M. Pringle ◽  
Jacob R. Goheen ◽  
Todd M. Palmer ◽  
Grace K. Charles ◽  
Elyse DeFranco ◽  
...  
Keyword(s):  
Population Level ◽  
Functional Redundancy ◽  
Plant Performance ◽  
Population Declines ◽  
Negative Effects ◽  
Ecological Processes ◽  
Large Herbivore ◽  
Positive Effects ◽  
Viable Seeds ◽  
The Impact

Large herbivorous mammals play an important role in structuring African savannahs and are undergoing widespread population declines and local extinctions, with the largest species being the most vulnerable. The impact of these declines on key ecological processes hinges on the degree of functional redundancy within large-herbivore assemblages, a subject that has received little study. We experimentally quantified the effects of three browser species (elephant, impala and dik-dik) on individual- and population-level attributes of Solanum campylacanthum ( Solanum incanum sensu lato ), an encroaching woody shrub, using semi-permeable exclosures that selectively removed different-sized herbivores. After nearly 5 years, shrub abundance was lowest where all browser species were present and increased with each successive species deletion. Different browsers ate the same plant species in different ways, thereby exerting distinct suites of direct and indirect effects on plant performance and density. Not all of these effects were negative: elephants and impala also dispersed viable seeds and indirectly reduced seed predation by rodents and insects. We integrated these diffuse positive effects with the direct negative effects of folivory using a simple population model, which reinforced the conclusion that different browsers have complementary net effects on plant populations, and further suggested that under some conditions, these net effects may even differ in direction.

scholarly journals Impact of Pratylenchus penetrans on Establishment of Red Raspberry

Plant Disease ◽  
2015 ◽  
Vol 99 (7) ◽  
pp. 939-946 ◽  
Author(s):  
Inga A. Zasada ◽  
Jerry E. Weiland ◽  
Z. Han ◽  
T. W. Walters ◽  
P. Moore
Keyword(s):  
Plant Biomass ◽  
Sandy Loam ◽  
Plant Productivity ◽  
Rubus Idaeus ◽  
Separate Experiment ◽  
Silt Loam ◽  
Pratylenchus Penetrans ◽  
Red Raspberry ◽  
Loam Soil ◽  
The Impact

The plant-parasitic nematode, Pratylenchus penetrans, is a major constraint to red raspberry (Rubus idaeus) production. To determine the impact of P. penetrans on the establishment and productivity of eight raspberry cultivars, R. niveus, and R. leucodermis, plants were grown in fumigated and nonfumigated soil. Then, soil and root populations of P. penetrans and plant productivity (vigor, cane height, biomass, and yield) were monitored over 2 years. In a separate experiment, the role that soil type plays in mediating P. penetrans populations and raspberry establishment was investigated. At 6 and 12 months after planting, population densities of P. penetrans were lower in fumigated than in nonfumigated soil; this trend continued 18 months after planting. All cultivars and R. leucodermis were found to be extremely susceptible to damage caused by P. penetrans. By the end of the experiment, yield was the most sensitive indicator of plant productivity among cultivars, with losses in nonfumigated soil ranging from 63 to 100% of those observed in fumigated soil. However, there was no difference in the productivity of R. niveus plants grown in nonfumigated versus fumigated soils. Results also indicated that the damage potential of P. penetrans was greater on sandy loam versus silt loam soils. The total plant biomass of ‘Meeker’ raspberry was 46% lower in a sandy loam soil containing P. penetrans compared with soil without P. penetrans; this trend was not observed consistently in a silt loam soil. Despite the fact that soil fumigation is increasingly more limited by regulations, this study shows the utility of fumigation in reducing P. penetrans populations for a sufficient period of time to ensure that newly planted raspberry seedlings can become successfully established.

scholarly journals Fungal Endophytes in Knock Out® Rose and Performance Effects of Entomopathogens on Marigold and Zinnia

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1791-1798 ◽  
Author(s):  
Kevin M. Heinz ◽  
Polly A. Harding ◽  
Maria Julissa Ek-Ramos ◽  
Heather Hernandez ◽  
Peter C. Krauter ◽  
...  
Keyword(s):  
Plant Growth ◽  
Fungal Endophytes ◽  
Plant Performance ◽  
Plant Responses ◽  
Natural Occurrence ◽  
Aesthetic Quality ◽  
Knock Out ◽  
Positive Effects ◽  
Fungal Entomopathogens ◽  
The Impact

Endophytic fungi are increasingly studied for their ability to enhance plant performance in field crops, yet there are few equivalent studies in floricultural crops. Given the economic importance of these crops and pressures faced by growers to produce plants of high aesthetic quality, we surveyed the natural occurrence of foliar fungal endophytes in Knock Out® roses to identify candidate beneficial isolates. We also tested the effects of entomopathogenic fungal inocula on marigold and zinnia plant growth using different application approaches. Our survey of Knock Out® rose foliage collected from five sites within central Texas revealed at least 24 different fungal genera and 30 probable species, including some isolates providing plant stress tolerance and pathogens or antagonists of insects and nematode pests. The effects of entomopathogen inocula on plant growth varied with host plant (marigold vs. zinnia) and inoculation method (soil drench vs. seed soak). Plant responses were complex, but inoculation with Isaria fumosorosea Wize tended to have a negative effect on plant performance characteristics whereas Beauveria bassiana (Bals.-Criv.) Vuill. tended to have positive effects. When applied to marigold as a seedcoating, I. fumosorosea reduced germination, seedling fresh weight, and produced seedlings with a less compact form. By contrast, seeds inoculated with B. bassiana required less time to germinate, had higher germination rates, and increased the plant compactness. These results show that the impact of fungal entomopathogens applied as endophytes depends on the specific fungi-plant combination being examined. The effect of plant inoculation with entomopathogenic fungi within a pest management context requires further evaluation.

Income Diversification and Bank Efficiency in Vietnam

2017 ◽  
pp. 52-67
Author(s):  
Sang Nguyen Minh
Keyword(s):  
Regression Model ◽  
Commercial Banks ◽  
Banking System ◽  
Operational Efficiency ◽  
Commercial Banking ◽  
Tobit Regression ◽  
Income Diversification ◽  
Positive Effects ◽  
Study Results ◽  
The Impact

This study uses the DEA (Data Envelopment Analysis) method to estimate the technical efficiency index of 34 Vietnamese commercial banks in the period 2007-2015, and then it analyzes the impact of income diversification on the operational efficiency of Vietnamese commercial banks through a censored regression model - the Tobit regression model. Research results indicate that income diversification has positive effects on the operational efficiency of Vietnamese commercial banks in the research period. Based on study results, in this research some recommendations forpolicy are given to enhance the operational efficiency of Vietnam’s commercial banking system.

Impact of Digitalization on Service Work in Knowledge-Intensive Business Services: An Empirical Study in Tax Consultancies

2019 ◽  
Vol 3 (4) ◽  
pp. 209-222
Author(s):  
Philipp K. Görs ◽  
Henning Hummert ◽  
Anne Traum ◽  
Friedemann W. Nerdinger
Keyword(s):  
Work Engagement ◽  
Service Work ◽  
Psychological Consequences ◽  
Business Services ◽  
Knowledge Intensive Business Services ◽  
Positive Effects ◽  
Knowledge Intensive ◽  
The Impact ◽  
Positive Effect ◽  
Special Case

Digitalization is a megatrend, but there is relatively little knowledge about its consequences for service work in general and specifically in knowledge-intensive business services (KIBS). We studied the impact of digitalization on psychological consequences for employees in tax consultancies as a special case of KIBS. We compare two tax consulting jobs with very different job demands, those of tax consultants (TCs) and assistant tax consultants (ATCs). The results show that the extent of digitalization at the workplace level for ATCs correlates significantly positively with their job satisfaction. For TCs, the same variable correlates positively with their work engagement. These positive effects of digitalization are mediated in the case of ATCs by the impact on important job characteristics. In the case of TCs, which already have very good working conditions, the impact is mediated by the positive effect on self-efficacy. Theoretical and practical consequences of these results are discussed.

HOW CLIMATE CHANGE CAN INFLUENCE THE AGRICULTURE IN UKRAINE: A REVIEW

2020 ◽  
Author(s):  
N. Maidanovych ◽  
Keyword(s):  
Climate Change ◽  
Crop Yields ◽  
Soil Surface ◽  
Winter Period ◽  
Negative Consequences ◽  
Resource Saving ◽  
Impact Of Climate Change ◽  
Positive Effects ◽  
Average Annual Temperature ◽  
The Impact

The purpose of this work is to review and analyze the main results of modern research on the impact of climate change on the agro-sphere of Ukraine. Results. Analysis of research has shown that the effects of climate change on the agro-sphere are already being felt today and will continue in the future. The observed climate changes in recent decades have already significantly affected the shift in the northern direction of all agro-climatic zones of Europe, including Ukraine. From the point of view of productivity of the agro-sphere of Ukraine, climate change will have both positive and negative consequences. The positives include: improving the conditions of formation and reducing the harvesting time of crop yields; the possibility of effective introduction of late varieties (hybrids), which require more thermal resources; improving the conditions for overwintering crops; increase the efficiency of fertilizer application. Model estimates of the impact of climate change on wheat yields in Ukraine mainly indicate the positive effects of global warming on yields in the medium term, but with an increase in the average annual temperature by 2 ° C above normal, grain yields are expected to decrease. The negative consequences of the impact of climate change on the agrosphere include: increased drought during the growing season; acceleration of humus decomposition in soils; deterioration of soil moisture in the southern regions; deterioration of grain quality and failure to ensure full vernalization of grain; increase in the number of pests, the spread of pathogens of plants and weeds due to favorable conditions for their overwintering; increase in wind and water erosion of the soil caused by an increase in droughts and extreme rainfall; increasing risks of freezing of winter crops due to lack of stable snow cover. Conclusions. Resource-saving agricultural technologies are of particular importance in the context of climate change. They include technologies such as no-till, strip-till, ridge-till, which make it possible to partially store and accumulate mulch on the soil surface, reduce the speed of the surface layer of air and contribute to better preservation of moisture accumulated during the autumn-winter period. And in determining the most effective ways and mechanisms to reduce weather risks for Ukrainian farmers, it is necessary to take into account the world practice of climate-smart technologies.

Sign in / Sign up

Export Citation Format

Share Document