scholarly journals Priority effects alter interaction outcomes in a legume–rhizobium mutualism

2021 ◽  
Vol 288 (1946) ◽  
pp. 20202753
Author(s):  
Julia A. Boyle ◽  
Anna K. Simonsen ◽  
Megan E. Frederickson ◽  
John R. Stinchcombe
Keyword(s):  
Community Structure ◽  
Priority Effects ◽  
Plant Performance ◽  
Nitrogen Fixing ◽  
High Quality ◽  
Multiple Partners ◽  
Medicago Lupulina ◽  
Interaction Order ◽  
Opposite Order ◽  
Open Question

Priority effects occur when the order of species arrival affects the final community structure. Mutualists often interact with multiple partners in different orders, but if or how priority effects alter interaction outcomes is an open question. In the field, we paired the legume Medicago lupulina with two nodulating strains of Ensifer bacteria that vary in nitrogen-fixing ability. We inoculated plants with strains in different orders and measured interaction outcomes. The first strain to arrive primarily determined plant performance and final relative abundances of rhizobia on roots. Plants that received effective microbes first and ineffective microbes second grew larger than plants inoculated with the same microbes in the opposite order. Our results show that mutualism outcomes can be influenced not just by partner identity, but by the interaction order. Furthermore, hosts receiving high-quality mutualists early can better tolerate low-quality symbionts later, indicating that priority effects may help explain the persistence of ineffective symbionts.

scholarly journals Priority effects alter interaction outcomes in a legume-rhizobium mutualism

2020 ◽  
Author(s):  
Julia A. Boyle ◽  
Anna K. Simonsen ◽  
Megan E. Frederickson ◽  
John R. Stinchcombe
Keyword(s):  
Community Structure ◽  
Priority Effects ◽  
Plant Performance ◽  
Nitrogen Fixing ◽  
High Quality ◽  
Multiple Partners ◽  
Medicago Lupulina ◽  
Interaction Order ◽  
Opposite Order ◽  
Open Question

AbstractPriority effects occur when the order of species arrival affects final community structure. Mutualists often interact with multiple partners in different orders, but if or how priority effects alter interaction outcomes is an open question. In the field, we paired the legume Medicago lupulina with two nodulating strains of Ensifer bacteria that vary in nitrogen-fixing ability. We inoculated plants with strains in different orders and measured interaction outcomes. The first strain to arrive primarily determined plant performance and final relative abundances of rhizobia on roots. Plants that received effective microbes first and ineffective microbes second grew larger than plants inoculated with the same microbes in opposite order. Our results show that mutualism outcomes can be influenced not just by partner identity, but by interaction order. Furthermore, hosts receiving high-quality mutualists early can better tolerate low-quality symbionts later, indicating priority effects may help explain the persistence of ineffective symbionts.

scholarly journals The plant circadian clock influences rhizosphere community structure and function

2017 ◽  
Author(s):  
Charley J. Hubbard ◽  
Marcus T. Brock ◽  
Linda T.A. van Diepen ◽  
Loïs Maignien ◽  
Brent E. Ewers ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Circadian Clock ◽  
Structure And Function ◽  
Plant Performance ◽  
Wild Type ◽  
Night Time ◽  
History Of ◽  
And Function ◽  
Rhizosphere Community

AbstractPlants alter chemical and physical properties of soil, and thereby influence rhizosphere microbial community structure. The structure of microbial communities may in turn affect plant performance. Yet, outside of simple systems with pairwise interacting partners, the plant genetic pathways that influence microbial community structure remain largely unknown, as are the performance feedbacks of microbial communities selected by the host plant genotype. We investigated the role of the plant circadian clock in shaping rhizosphere community structure and function. We performed 16S rRNA gene sequencing to characterize rhizosphere bacterial communities of Arabidopsis thaliana between day and night time points, and tested for differences in community structure between wild-type (Ws) vs. clock mutant (toc1-21, ztl-30) genotypes. We then characterized microbial community function, by growing wild-type plants in soils with an overstory history of Ws, toc1-21 or ztl-30 and measuring plant performance. We observed that rhizosphere community structure varied between day and night time points, and clock misfunction significantly altered rhizosphere communities. Finally, wild-type plants germinated earlier and were larger when inoculated with soils having an overstory history of wild-type in comparison to clock mutant genotypes. Our findings suggest the circadian clock of the plant host influences rhizosphere community structure and function.

Fine Bubble Aeration Using a High Density Diffuser System

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2437-2440 ◽  
Author(s):  
K. Thatcher
Keyword(s):  
Activated Sludge ◽  
Oxygen Transfer ◽  
Oxygen Demand ◽  
High Density ◽  
Plant Performance ◽  
Energy Usage ◽  
High Quality ◽  
Transfer Rates ◽  
Fine Bubble ◽  
Activated Sludge Processes

Current developments with the activated sludge processes with highly concentrated effluents highlight the requirement to (a) reduce energy usage (b) promote the production of high quality effluent. Having observed the efforts being made to improve plant performance we became aware that current methods had to be improved. It was also noted that a period of stagnation had occurred in the development of effective aeration systems. Improved aeration methods are needed which would allow for oxygen transfer efficiencies to be greater than 2kg/kWh. Such oxygen transfer rates should be continually variable in line with the oxygen demand prevailing at any given time. In our study of activated sludge plants we found that operational and electrical/mechanical maintenance was proving to be time consuming and very costly. With these problems in mind we have designed and developed the Fine Bubble High Density Diffuser System.

scholarly journals Incremental Density-Based Link Clustering Algorithm for Community Detection in Dynamic Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fanrong Meng ◽  
Feng Zhang ◽  
Mu Zhu ◽  
Yan Xing ◽  
Zhixiao Wang ◽  
...  
Keyword(s):  
Community Structure ◽  
Complex Networks ◽  
Community Detection ◽  
Network Topology ◽  
Clustering Algorithm ◽  
Dynamic Networks ◽  
Experimental Results ◽  
Extended Version ◽  
High Quality ◽  
Detection Algorithms

Community detection in complex networks has become a research hotspot in recent years. However, most of the existing community detection algorithms are designed for the static networks; namely, the connections between the nodes are invariable. In this paper, we propose an incremental density-based link clustering algorithm for community detection in dynamic networks, iDBLINK. This algorithm is an extended version of DBLINK which is proposed in our previous work. It can update the local link community structure in the current moment through the change of similarity between the edges at the adjacent moments, which includes the creation, growth, merging, deletion, contraction, and division of link communities. Extensive experimental results demonstrate that iDBLINK not only has a great time efficiency, but also maintains a high quality community detection performance when the network topology is changing.

scholarly journals Power Factor Compensation in Non-Sinusoidal Circuits Using Geometric Algebra and Evolutionary Algorithms

2019 ◽  
Author(s):  
Francisco G. Montoya ◽  
Alfredo Alcayde ◽  
Francisco M. Arrabal-Campos ◽  
Raul Baños
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Evolutionary Algorithms ◽  
Power Factor ◽  
Geometric Algebra ◽  
Active Filters ◽  
High Quality ◽  
Passive Filters ◽  
Algebra Theory ◽  
Open Question

Non-linear loads in circuits cause the appearance of harmonic disturbances both in voltage and current. In order to minimize the effects of these disturbances and, therefore, to control over the flow of electricity between the source and the load, they are often used passive or active filters. Nevertheless, determining the type of filter and the characteristics of their elements is not a trivial task. In fact, the development of algorithms for calculating the parameters of filters is still an open question. This paper analyzes the use of genetic algorithms to maximize the power factor compensation in non-sinusoidal circuits using passive filters, while concepts of geometric algebra theory are used to represent the flow of power in the circuits. According to the results obtained in different case studies, it can be concluded that the genetic algorithm obtain high quality solutions that could be generalized to similar problems of any dimension.

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