1
|
Soininen EM, Neby M. Small rodent population cycles and plants - after 70 years, where do we go? Biol Rev Camb Philos Soc 2024; 99:265-294. [PMID: 37827522 DOI: 10.1111/brv.13021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/14/2023]
Abstract
Small rodent population cycles characterise northern ecosystems, and the cause of these cycles has been a long-lasting central topic in ecology, with trophic interactions currently considered the most plausible cause. While some researchers have rejected plant-herbivore interactions as a cause of rodent cycles, others have continued to research their potential roles. Here, we present an overview of whether plants can cause rodent population cycles, dividing this idea into four different hypotheses with different pathways of plant impacts and related assumptions. Our systematic review of the existing literature identified 238 studies from 150 publications. This evidence base covered studies from the temperate biome to the tundra, but the studies were scattered across study systems and only a few specific topics were addressed in a replicated manner. Quantitative effects of rodents on vegetation was the best studied topic, and our evidence base suggests such that such effects may be most pronounced in winter. However, the regrowth of vegetation appears to take place too rapidly to maintain low rodent population densities over several years. The lack of studies prevented assessment of time lags in the qualitative responses of vegetation to rodent herbivory. We conclude that the literature is currently insufficient to discard with confidence any of the four potential hypotheses for plant-rodent cycles discussed herein. While new methods allow analyses of plant quality across more herbivore-relevant spatial scales than previously possible, we argue that the best way forward to rejecting any of the rodent-plant hypotheses is testing specific predictions of dietary variation. Indeed, all identified hypotheses make explicit assumptions on how rodent diet taxonomic composition and quality will change across the cycle. Passing this bottleneck could help pinpoint where, when, and how plant-herbivore interactions have - or do not have - plausible effects on rodent population dynamics.
Collapse
Affiliation(s)
- Eeva M Soininen
- Department of Arctic and Marine Biology, UiT-The Arctic University of Norway, Postboks 6050 Langnes, Tromsø, 9037, Norway
| | - Magne Neby
- Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Høyvangvegen 40, Ridabu, 2322, Norway
| |
Collapse
|
2
|
Headrick KC, Juenger TE, Heckman RW. Plant physical defenses contribute to a latitudinal gradient in resistance to insect herbivory within a widespread perennial grass. AMERICAN JOURNAL OF BOTANY 2024; 111:e16260. [PMID: 38031482 DOI: 10.1002/ajb2.16260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 12/01/2023]
Abstract
PREMISE Herbivore pressure can vary across the range of a species, resulting in different defensive strategies. If herbivory is greater at lower latitudes, plants may be better defended there, potentially driving a latitudinal gradient in defense. However, relationships that manifest across the entire range of a species may be confounded by differences within genetic subpopulations, which may obscure the drivers of these latitudinal gradients. METHODS We grew plants of the widespread perennial grass Panicum virgatum in a common garden that included genotypes from three genetic subpopulations spanning an 18.5° latitudinal gradient. We then assessed defensive strategies of these plants by measuring two physical resistance traits-leaf mass per area (LMA) and leaf ash, a proxy for silica-and multiple measures of herbivory by caterpillars of the generalist herbivore fall armyworm (Spodoptera frugiperda). RESULTS Across all genetic subpopulations, low-latitude plants experienced less herbivory than high-latitude plants. Within genetic subpopulations, however, this relationship was inconsistent-the most widely distributed and phenotypically variable subpopulation (Atlantic) exhibited more consistent latitudinal trends than either of the other two subpopulations. The two physical resistance traits, LMA and leaf ash, were both highly heritable and positively associated with resistance to different measures of herbivory across all subpopulations, indicating their importance in defense against herbivores. Again, however, these relationships were inconsistent within subpopulations. CONCLUSIONS Defensive gradients that occur across the entire species range may not arise within localized subpopulations. Thus, identifying the drivers of latitudinal gradients in herbivory defense may depend on adequately sampling the diversity within a species.
Collapse
Affiliation(s)
- Kevin C Headrick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Thomas E Juenger
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
| | - Robert W Heckman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, 78712, USA
| |
Collapse
|
3
|
Thorne SJ, Maathuis FJM, Hartley SE. Induction of silicon defences in wheat landraces is local, not systemic, and driven by mobilization of soluble silicon to damaged leaves. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:5363-5373. [PMID: 37314063 DOI: 10.1093/jxb/erad224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 06/13/2023] [Indexed: 06/15/2023]
Abstract
In response to herbivory, many grasses, including crops such as wheat, accumulate significant levels of silicon (Si) as an antiherbivore defence. Damage-induced increases in Si can be localized in damaged leaves or be more systemic, but the mechanisms leading to these differences in Si distribution remain untested. Ten genetically diverse wheat landraces (Triticum aestivum) were used to assess genotypic variation in Si induction in response to mechanical damage and how this was affected by exogenous Si supply. Total and soluble Si levels were measured in damaged and undamaged leaves as well as in the phloem to test how Si was allocated to different parts of the plant after damage. Localized, but not systemic, induction of Si defences occurred, and was more pronounced when plants had supplemental Si. Damaged plants had significant increases in Si concentration in their damaged leaves, while the Si concentration in undamaged leaves decreased, such that there was no difference in the average Si concentration of damaged and undamaged plants. The increased Si in damaged leaves was due to the redirection of soluble Si, present in the phloem, from undamaged to damaged plant parts, potentially a more cost-effective defence mechanism for plants than increased Si uptake.
Collapse
Affiliation(s)
- Sarah J Thorne
- Plants, Photosynthesis, and Soil, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Susan E Hartley
- Plants, Photosynthesis, and Soil, School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| |
Collapse
|
4
|
Edwards PD, Palme R, Boonstra R. Is chronic stress a causal mechanism for small mammal population cycles? Reconciling the evidence. Oecologia 2023; 201:609-623. [PMID: 36864247 DOI: 10.1007/s00442-023-05338-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 02/17/2023] [Indexed: 03/04/2023]
Abstract
Chronic stress has long been hypothesized to play a role in driving population cycles. Christian (1950) hypothesized that high population density results in chronic stress and mass "die-offs" in small mammal populations. Updated variations of this hypothesis propose that chronic stress at high population density may reduce fitness, reproduction, or program aspects of phenotype, driving population declines. We tested the effect of density on the stress axis in meadow voles (Microtus pennsylvanicus) by manipulating population density in field enclosures over three years. Using fecal corticosterone metabolites as a non-invasive measure of glucocorticoid (GC) concentrations, we found that density alone was not associated with GC differences. However, we found that the seasonal relationship of GC levels differed by density treatment, with high-density populations having elevated GC levels early in the breeding season and decreasing towards late summer. We additionally tested hippocampal glucocorticoid receptor and mineralocorticoid receptor gene expression in juvenile voles born at different densities, with the hypothesis that high density may reduce receptor expression, altering negative feedback of the stress axis. We found that females had marginally higher glucocorticoid receptor expression at high density, no effect in males, and no detectable effect of density on mineralocorticoid receptor expression in either sex. Hence, we found no evidence that high density directly impairs negative feedback in the hippocampus, but rather female offspring may be better equipped for negative feedback. We compare our findings with prior studies to attempt to disentangle the complicated relationship between density, seasonality, sex, reproduction and the stress axis.
Collapse
Affiliation(s)
- Phoebe D Edwards
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 1A1, Canada.
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada.
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada.
| | - Rupert Palme
- Department of Biomedical Sciences, University of Veterinary Medicine, 1210, Vienna, Austria
| | - Rudy Boonstra
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, M5S 1A1, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada
| |
Collapse
|
5
|
Edwards PD, Boonstra R, Oli MK. An experimental analysis of density dependence in meadow voles: Within-season and delayed effects. Ecology 2023; 104:e4008. [PMID: 36807294 DOI: 10.1002/ecy.4008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 12/26/2022] [Accepted: 01/26/2023] [Indexed: 02/20/2023]
Abstract
Wild mammal populations exhibit a variety of dynamics, ranging from fairly stable with little change in population size over time to high-amplitude cyclic or erratic fluctuations. A persistent question in population ecology is why populations fluctuate as they do. Answering this seemingly simple question has proven to be challenging. Broadly, density-dependent feedback mechanisms should allow populations to grow at low density and slow or halt growth at high density. However, experimental tests of what demographic processes result in density-dependent feedback and on what timescale have proven elusive. Here, we used replicated density perturbation experiments and capture-mark-recapture analyses to test density-dependent population growth in populations of meadow voles (Microtus pennsylvanicus) during the summer breeding season by manipulating founding population density and observing the pattern of survival, reproduction, and population growth. High population density had no consistent effect on survival rates but generally negatively influenced recruitment and population growth rates. However, these density-dependent effects varied within the breeding season and across years. Our study provides evidence that density-dependent feedback mechanisms operate at finer time scales than previously believed and that process, additively with delayed year effects, is key to understanding multiyear population demography.
Collapse
Affiliation(s)
- Phoebe D Edwards
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Madan K Oli
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, Florida, USA.,School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| |
Collapse
|
6
|
Borowski Z, Zub K, Sulwiński M, Suska‐Malawska M, Konarzewski M. Plant-herbivore interactions: Combined effect of groundwater level, root vole grazing, and sedge silicification. Ecol Evol 2021; 11:16047-16054. [PMID: 34824810 PMCID: PMC8601873 DOI: 10.1002/ece3.8275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/25/2021] [Accepted: 10/12/2021] [Indexed: 11/21/2022] Open
Abstract
Accumulation of silica (Si) by plants can be driven by (1) herbivory pressure (and therefore plant-herbivore interactions), (2) geohydrological cycles, or (3) a combination of (1) and (2), with (1-3) possibly affecting Si concentration with a 1-year delay.To identify the relative significance of (1-3), we analyzed the concentration of Si in fibrous tussock sedge (Carex appropinquata), the population density of the root vole (Microtus oeconomus), and the groundwater level, over 11 years.The largest influence of autumn Si concentration in leaves (Sileaf) was on the level of the current-year groundwater table, which was positive and accounted for 13.3% of its variance. The previous year's vole population density was weakly positively correlated with Sileaf, and it alone explained 9.5% of its variance.The only variable found to have a positive, significant effect on autumn Si concentration in rhizomes (Sirhiz) was the current-year spring water level, explaining as much as 60.9% of its variance.We conclude that the changes in Si concentration in fibrous tussock sedge are predominantly driven by hydrology, with vole population dynamics being secondary.Our results provide only partial support for the existence of plant-herbivore interactions, as we did not detect the significant effects of Si tussock concentration on the vole density dynamics. This was mainly due to the low level of silicification of sedges, which was insufficient to impinge herbivores.Future studies on plant-herbivore interactions should therefore aim at disentangling whether anti-herbivore protection is dependent on threshold values of herbivore population dynamics. Furthermore, studies on Si accumulation should focus on the effect of water-mediated Si availability.
Collapse
Affiliation(s)
| | - Karol Zub
- Mammal Research Institute Polish Academy of SciencesBiałowieżaPoland
| | - Marcin Sulwiński
- Faculty of Biology, Biological and Chemical Research CentreWarsaw UniversityWarsawPoland
| | | | | |
Collapse
|
7
|
Katz O, Puppe D, Kaczorek D, Prakash NB, Schaller J. Silicon in the Soil-Plant Continuum: Intricate Feedback Mechanisms within Ecosystems. PLANTS (BASEL, SWITZERLAND) 2021; 10:652. [PMID: 33808069 PMCID: PMC8066056 DOI: 10.3390/plants10040652] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/22/2021] [Accepted: 03/26/2021] [Indexed: 11/28/2022]
Abstract
Plants' ability to take up silicon from the soil, accumulate it within their tissues and then reincorporate it into the soil through litter creates an intricate network of feedback mechanisms in ecosystems. Here, we provide a concise review of silicon's roles in soil chemistry and physics and in plant physiology and ecology, focusing on the processes that form these feedback mechanisms. Through this review and analysis, we demonstrate how this feedback network drives ecosystem processes and affects ecosystem functioning. Consequently, we show that Si uptake and accumulation by plants is involved in several ecosystem services like soil appropriation, biomass supply, and carbon sequestration. Considering the demand for food of an increasing global population and the challenges of climate change, a detailed understanding of the underlying processes of these ecosystem services is of prime importance. Silicon and its role in ecosystem functioning and services thus should be the main focus of future research.
Collapse
Affiliation(s)
- Ofir Katz
- Dead Sea and Arava Science Center, Mt. Masada, Tamar Regional Council, 86910 Tamar, Israel
- Eilat Campus, Ben-Gurion University of the Negev, Hatmarim Blv, 8855630 Eilat, Israel
| | - Daniel Puppe
- Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany; (D.P.); (D.K.); (J.S.)
| | - Danuta Kaczorek
- Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany; (D.P.); (D.K.); (J.S.)
- Department of Soil Environment Sciences, Warsaw University of Life Sciences (SGGW), 02776 Warsaw, Poland
| | - Nagabovanalli B. Prakash
- Department of Soil Science and Agricultural Chemistry, University of Agricultural Sciences, GKVK, Bangalore 560065, India;
| | - Jörg Schaller
- Leibniz Centre for Agricultural Landscape Research (ZALF), 15374 Müncheberg, Germany; (D.P.); (D.K.); (J.S.)
| |
Collapse
|
8
|
Andreassen HP, Sundell J, Ecke F, Halle S, Haapakoski M, Henttonen H, Huitu O, Jacob J, Johnsen K, Koskela E, Luque-Larena JJ, Lecomte N, Leirs H, Mariën J, Neby M, Rätti O, Sievert T, Singleton GR, van Cann J, Vanden Broecke B, Ylönen H. Population cycles and outbreaks of small rodents: ten essential questions we still need to solve. Oecologia 2021; 195:601-622. [PMID: 33369695 PMCID: PMC7940343 DOI: 10.1007/s00442-020-04810-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/19/2020] [Indexed: 12/25/2022]
Abstract
Most small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most important issues that are essential for understanding the generality of small rodent population dynamics.
Collapse
Affiliation(s)
- Harry P Andreassen
- Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway
| | - Janne Sundell
- Lammi Biological Station, University of Helsinki, Pääjärventie 320, 16900, Lammi, Finland
| | - Fraucke Ecke
- Department of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences, Skogsmarksgränd, 90183, Umeå, Sweden
| | - Stefan Halle
- Institute of Ecology and Evolution, Friedrich Schiller University Jena, Dornburger Str. 159, 07743, Jena, Germany
| | - Marko Haapakoski
- Department of Biological and Environmental Science, Konnevesi Research Station, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Heikki Henttonen
- Terrestrial Population Dynamics, Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Otso Huitu
- Terrestrial Population Dynamics, Natural Resources Institute Finland, Latokartanonkaari 9, 00790, Helsinki, Finland
| | - Jens Jacob
- Federal Research Centre for Cultivated Plants, Vertebrate Research, Julius Kühn-Institut, Toppheideweg 88, 48161, Münster, Germany
| | - Kaja Johnsen
- Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway
| | - Esa Koskela
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Juan Jose Luque-Larena
- Departamento de Ciencias Agroforestales, Escuela Tecnica Superior de Ingenierıas Agrarias, Universidad de Valladolid, Campus La Yutera, Avenida de Madrid 44, 34004, Palencia, Spain
| | - Nicolas Lecomte
- Canada Research Chair in Polar and Boreal Ecology and Centre D'Études Nordiques, Department of Biology, Université de Moncton, 18 Avenue Antonine-Maillet, Moncton, NB, E1A 3E9, Canada
| | - Herwig Leirs
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitslain 1, 2610, Wilrijk, Belgium
| | - Joachim Mariën
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitslain 1, 2610, Wilrijk, Belgium
| | - Magne Neby
- Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Campus Evenstad, 2480, Koppang, Norway
| | - Osmo Rätti
- Arctic Centre, University of Lapland, P.O. Box 122, 96101, Rovaniemi, Finland
| | - Thorbjörn Sievert
- Department of Biological and Environmental Science, Konnevesi Research Station, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Grant R Singleton
- International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines
- Natural Resources Institute, University of Greenwich, Chatham Marine, Kent, ME4 4TB, UK
| | - Joannes van Cann
- Department of Biological and Environmental Science, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland
| | - Bram Vanden Broecke
- Evolutionary Ecology Group, Department of Biology, University of Antwerp, Universiteitslain 1, 2610, Wilrijk, Belgium
| | - Hannu Ylönen
- Department of Biological and Environmental Science, Konnevesi Research Station, University of Jyväskylä, P.O. Box 35, 40014, Jyväskylä, Finland.
| |
Collapse
|
9
|
Brightly WH, Hartley SE, Osborne CP, Simpson KJ, Strömberg CAE. High silicon concentrations in grasses are linked to environmental conditions and not associated with C 4 photosynthesis. GLOBAL CHANGE BIOLOGY 2020; 26:7128-7143. [PMID: 32897634 DOI: 10.1111/gcb.15343] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
The uptake and deposition of silicon (Si) as silica phytoliths is common among land plants and is associated with a variety of functions. Among these, herbivore defense has received significant attention, particularly with regard to grasses and grasslands. Grasses are well known for their high silica content, a trait which has important implications ranging from defense to global Si cycling. Here, we test the classic hypothesis that C4 grasses evolved stronger mechanical defenses than C3 grasses through increased phytolith deposition, in response to extensive ungulate herbivory ("C4 -grazer hypothesis"). Despite mixed support, this hypothesis has received broad attention, even outside the realm of plant biology. Because C3 and C4 grasses typically dominate in different climates, with the latter more abundant in hot, dry regions, we also investigated the effects of water availability and temperature on Si deposition. We compiled a large dataset of grasses grown under controlled environmental conditions. Using phylogenetically informed generalized linear mixed models and character evolution models, we evaluated whether photosynthetic pathway or growth condition influenced Si concentration. We found that C4 grasses did not show consistently elevated Si concentrations compared with C3 grasses. High temperature treatments were associated with increased concentration, especially in taxa adapted to warm regions. Although the effect was less pronounced, reduced water treatment also promoted silica deposition, with slightly stronger response in dry habitat species. The evidence presented here rejects the "C4 -grazer hypothesis." Instead, we propose that the tendency for C4 grasses to outcompete C3 species under hot, dry conditions explains previous observations supporting this hypothesis. These findings also suggest a mechanism via which anthropogenic climate change may influence silica deposition in grasses and, by extension, alter the important ecological and geochemical processes it affects.
Collapse
Affiliation(s)
- William H Brightly
- Department of Biology and the Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Sue E Hartley
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Colin P Osborne
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Kimberley J Simpson
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Caroline A E Strömberg
- Department of Biology and the Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| |
Collapse
|
10
|
Waterman JM, Hall CR, Mikhael M, Cazzonelli CI, Hartley SE, Johnson SN. Short‐term resistance that persists: Rapidly induced silicon anti‐herbivore defence affects carbon‐based plant defences. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13702] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jamie M. Waterman
- Hawkesbury Institute for the EnvironmentWestern Sydney University Richmond NSW Australia
| | - Casey R. Hall
- Hawkesbury Institute for the EnvironmentWestern Sydney University Richmond NSW Australia
| | - Meena Mikhael
- School of Medicine Western Sydney University Campbelltown NSW Australia
| | | | | | - Scott N. Johnson
- Hawkesbury Institute for the EnvironmentWestern Sydney University Richmond NSW Australia
| |
Collapse
|
11
|
Croy JR, Meyerson LA, Allen WJ, Bhattarai GP, Cronin JT. Lineage and latitudinal variation inPhragmites australistolerance to herbivory: implications for invasion success. OIKOS 2020. [DOI: 10.1111/oik.07260] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Jordan R. Croy
- Dept of Biological Sciences, Louisiana State Univ. Baton Rouge LA 70803 USA
- Dept of Ecology and Evolutionary Biology, Univ. of California Irvine CA 92697 USA
| | - Laura A. Meyerson
- Dept of Natural Resource Sciences, Univ. of Rhode Island Kingston RI USA
| | - Warwick J. Allen
- Dept of Biological Sciences, Louisiana State Univ. Baton Rouge LA 70803 USA
- The Bio‐Protection Research Centre, School of Biological Sciences, Univ. of Canterbury Christchurch New Zealand
| | - Ganesh P. Bhattarai
- Dept of Biological Sciences, Louisiana State Univ. Baton Rouge LA 70803 USA
- Dept of Entomology, Kansas State Univ. Manhattan KS USA
| | - James T. Cronin
- Dept of Biological Sciences, Louisiana State Univ. Baton Rouge LA 70803 USA
| |
Collapse
|
12
|
Quigley KM, Griffith DM, Donati GL, Anderson TM. Soil nutrients and precipitation are major drivers of global patterns of grass leaf silicification. Ecology 2020; 101:e03006. [PMID: 32020594 PMCID: PMC7317429 DOI: 10.1002/ecy.3006] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 11/26/2019] [Accepted: 12/20/2019] [Indexed: 11/23/2022]
Abstract
Grasses accumulate high concentrations of silicon (Si) in their tissues, with potential benefits including herbivore defense, improved water balance, and reduced leaf construction costs. Although Si is one of the most widely varying leaf constituents among individuals, species, and ecosystems, the environmental forces driving this variation remain elusive and understudied. To understand relationships between environmental factors and grass Si accumulation better, we analyzed foliar chemistry of grasses from 17 globally distributed sites where nutrient inputs and grazing were manipulated. These sites span natural gradients in temperature, precipitation, and underlying soil properties, which allowed us to assess the relative importance of soil moisture and nutrients across variation in climate. Foliar Si concentration did not respond to large mammalian grazer exclusion, but significant variation in herbivore abundance among sites may have precluded the observation of defoliation effects at these sites. However, nutrient addition consistently reduced leaf Si, especially at sites with low soil nitrogen prior to nutrient addition. Additionally, a leaf‐level trade‐off between Si and carbon (C) existed that was stronger at arid sites than mesic sites. Our results suggest soil nutrient limitation favors investment in Si over C‐based leaf construction, and that fixing C is especially costly relative to assimilating Si when water is limiting. Our results demonstrate the importance of soil nutrients and precipitation as key drivers of global grass silicification patterns.
Collapse
Affiliation(s)
- Kathleen M Quigley
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109, USA
| | - Daniel M Griffith
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109, USA
| | - George L Donati
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, 27109, USA
| | - T Michael Anderson
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, 27109, USA
| |
Collapse
|
13
|
Nawaz MA, Zakharenko AM, Zemchenko IV, Haider MS, Ali MA, Imtiaz M, Chung G, Tsatsakis A, Sun S, Golokhvast KS. Phytolith Formation in Plants: From Soil to Cell. PLANTS (BASEL, SWITZERLAND) 2019; 8:E249. [PMID: 31357485 PMCID: PMC6724085 DOI: 10.3390/plants8080249] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 01/19/2023]
Abstract
Silica is deposited extra- and intracellularly in plants in solid form, as phytoliths. Phytoliths have emerged as accepted taxonomic tools and proxies for reconstructing ancient flora, agricultural economies, environment, and climate. The discovery of silicon transporter genes has aided in the understanding of the mechanism of silicon transport and deposition within the plant body and reconstructing plant phylogeny that is based on the ability of plants to accumulate silica. However, a precise understanding of the process of silica deposition and the formation of phytoliths is still an enigma and the information regarding the proteins that are involved in plant biosilicification is still scarce. With the observation of various shapes and morphologies of phytoliths, it is essential to understand which factors control this mechanism. During the last two decades, significant research has been done in this regard and silicon research has expanded as an Earth-life science superdiscipline. We review and integrate the recent knowledge and concepts on the uptake and transport of silica and its deposition as phytoliths in plants. We also discuss how different factors define the shape, size, and chemistry of the phytoliths and how biosilicification evolved in plants. The role of channel-type and efflux silicon transporters, proline-rich proteins, and siliplant1 protein in transport and deposition of silica is presented. The role of phytoliths against biotic and abiotic stress, as mechanical barriers, and their use as taxonomic tools and proxies, is highlighted.
Collapse
Affiliation(s)
- Muhammad Amjad Nawaz
- Education and Scientific Center of Nanotechnology, Far Eastern Federal University, 690950 Vladivostok, Russia
| | | | | | - Muhammad Sajjad Haider
- Department of Forestry, College of Agriculture, University of Sargodha, 40100 Sargodha, Pakistan
| | - Muhammad Amjad Ali
- Department of Plant Pathology, University of Agriculture, 38040 Faisalabad, Pakistan
- Center of Agricultural Biochemistry and Biotechnology (CABB), University of Agriculture, 38040 Faisalabad, Pakistan
| | - Muhammad Imtiaz
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, 38040 Faisalabad, Pakistan
| | - Gyuhwa Chung
- Department of Biotechnology, Chonnam National University, 59626 Yeosu-Si, Korea
| | - Aristides Tsatsakis
- Department of Toxicology and Forensics, School of Medicine, University of Crete, Heraklion GR-71003, Crete, Greece
| | - Sangmi Sun
- Department of Biotechnology, Chonnam National University, 59626 Yeosu-Si, Korea.
| | - Kirill Sergeyevich Golokhvast
- Education and Scientific Center of Nanotechnology, Far Eastern Federal University, 690950 Vladivostok, Russia.
- Pacific Geographical Institute, FEB RAS, 7 Radio street, Vladivostok 690014, Russia.
| |
Collapse
|
14
|
Oli MK. Population cycles in voles and lemmings: state of the science and future directions. Mamm Rev 2019. [DOI: 10.1111/mam.12156] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Madan K. Oli
- Department of Wildlife Ecology and ConservationUniversity of Florida 110 Newins‐Ziegler Hall Gainesville FL 32611 USA
| |
Collapse
|
15
|
Vicari M, Puentes A, Granath G, Georgeff J, Strathdee F, Bazely DR. Unpacking multi-trophic herbivore-grass-endophyte interactions: feedbacks across different scales in vegetation responses to Soay sheep herbivory. Naturwissenschaften 2018; 105:66. [PMID: 30460621 PMCID: PMC6244524 DOI: 10.1007/s00114-018-1590-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/26/2018] [Accepted: 10/23/2018] [Indexed: 11/28/2022]
Abstract
Grazing can induce changes in both plant productivity and nutritional quality, which may subsequently influence herbivore carrying capacity. While research on Soay sheep (Ovis aries L.) dynamics on Hirta Island in the St. Kilda archipelago has elucidated the complexity of population drivers, including parasites, the role of herbivore-generated feedbacks as an intrinsic regulating factor remains unclear. The sheep lack large predators and every 3-9 years undergo population crashes (overcompensatory mortality). We investigated the effects of grazing on (1) sward productivity and (2) quality (toxicity) of the primary forage species, red fescue (Festuca rubra L.), which is highly infected by an alkaloid-synthesizing fungal endophyte. Grazing had a negative impact on both forage quantity and quality. At higher sheep densities, impacts on sward growth were magnified, resulting in a nonlinear relationship with plant productivity. Simultaneously, endophyte hyphal load (and by inference, toxicity) peaked close to the time of a crash. A greenhouse experiment showed that alkaloid concentration in F. rubra increased in response to artificial defoliation. We conclude that at high sheep densities, grazing-mediated reductions in productivity, together with sustained alkaloid production, are likely to influence sheep dynamics. Future research should consider the interactive effects of forage toxicity, quantity, and nutritional content.
Collapse
Affiliation(s)
- Mark Vicari
- Department of Biology, York University, 4700 Keele St., Toronto, ON, Canada.
| | - Adriana Puentes
- Department of Ecology, Swedish University of Agricultural Sciences, Box 7044, 750 07, Uppsala, Sweden
| | - Gustaf Granath
- Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Norbyvägen 18D, Uppsala, Sweden
| | - Jennifer Georgeff
- Department of Biology, York University, 4700 Keele St., Toronto, ON, Canada
| | - Fiona Strathdee
- Department of Biology, York University, 4700 Keele St., Toronto, ON, Canada
| | - Dawn R Bazely
- Department of Biology, York University, 4700 Keele St., Toronto, ON, Canada
| |
Collapse
|
16
|
Ruffino L, Hartley SE, DeGabriel JL, Lambin X. Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography. Ecol Evol 2018; 8:7752-7762. [PMID: 30250660 PMCID: PMC6145023 DOI: 10.1002/ece3.4204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 03/13/2018] [Accepted: 04/19/2018] [Indexed: 11/06/2022] Open
Abstract
Grazing-induced changes in plant quality have been suggested to drive the negative delayed density dependence exhibited by many herbivore species, but little field evidence exists to support this hypothesis. We tested a key premise of the hypothesis that reciprocal feedback between vole grazing pressure and the induction of anti-herbivore silicon defenses in grasses drives observed population cycles in a large-scale field experiment in northern England. We repeatedly reduced population densities of field voles (Microtus agrestis) on replicated 1-ha grassland plots at Kielder Forest, northern England, over a period of 1 year. Subsequently, we tested for the impact of past density on vole life history traits in spring, and whether these effects were driven by induced silicon defenses in the voles' major over-winter food, the grass Deschampsia caespitosa. After several months of density manipulation, leaf silicon concentrations diverged and averaged 22% lower on sites where vole density had been reduced, but this difference did not persist beyond the period of the density manipulations. There were no significant effects of our density manipulations on vole body mass, spring population growth rate, or mean date for the onset of spring reproduction the following year. These findings show that grazing by field voles does induce increased silicon defenses in grasses at a landscape scale. However, at the vole densities encountered, levels of plant damage appear to be below those needed to induce changes in silicon levels large and persistent enough to affect vole performance, confirming the threshold effects we have previously observed in laboratory-based studies. Our findings do not support the plant quality hypothesis for observed vole population cycles in northern England, at least over the range of vole densities that now prevail here.
Collapse
Affiliation(s)
- Lise Ruffino
- School of Biological SciencesUniversity of AberdeenAberdeenUK
| | | | - Jane L. DeGabriel
- School of Biological SciencesUniversity of AberdeenAberdeenUK
- NSW Office of Environment and HeritageSydneyNSWAustralia
| | - Xavier Lambin
- School of Biological SciencesUniversity of AberdeenAberdeenUK
| |
Collapse
|
17
|
Schmidt JH, Rexstad EA, Roland CA, McIntyre CL, MacCluskie MC, Flamme MJ. Weather-driven change in primary productivity explains variation in the amplitude of two herbivore population cycles in a boreal system. Oecologia 2017; 186:435-446. [PMID: 29170821 DOI: 10.1007/s00442-017-4004-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 11/06/2017] [Indexed: 11/29/2022]
Abstract
Vertebrate populations throughout the circumpolar north often exhibit cyclic dynamics, and predation is generally considered to be a primary driver of these cycles in a variety of herbivore species. However, weather and climate play a role in entraining cycles over broad landscapes and may alter cyclic dynamics, although the mechanism by which these processes operate is uncertain. Experimental and observational work has suggested that weather influences primary productivity over multi-year time periods, suggesting a pathway through which weather and climate may influence cyclic herbivore dynamics. Using long-term monitoring data, we investigated the relationships among multi-year weather conditions, measures of primary productivity, and the abundance of two cyclic herbivore species: snowshoe hare and northern red-backed vole. We found that precipitation (rain and snow) and growing season temperatures were strongly associated with variation in primary productivity over multi-year time horizons. In turn, fourfold variation in the amplitude of both the hare and vole cycles observed in our study area corresponded to long-term changes in primary productivity. The congruence of our results for these two species suggests a general mechanism by which weather and climate might influence cyclic herbivore population dynamics. Our findings also suggested that the association between climate warming and the disappearance of cycles might be initiated by changes in primary productivity. This work provides an explanation for observed influences of weather and climate on primary productivity and population cycles and will help our collective understanding of how future climate warming may influence these ecological phenomena in the future.
Collapse
Affiliation(s)
- Joshua H Schmidt
- US National Park Service, Central Alaska Network, 4175 Geist Road, Fairbanks, AK, 99709, USA.
| | - Eric A Rexstad
- Research Unit for Wildlife Population Assessment, Centre for Research into Ecological and Environmental Modelling, University of St. Andrews, St Andrews, KY16 9LZ, UK
| | - Carl A Roland
- US National Park Service, Central Alaska Network, 4175 Geist Road, Fairbanks, AK, 99709, USA.,US National Park Service, Denali National Park and Preserve, 4175 Geist Road, Fairbanks, AK, 99709, USA
| | - Carol L McIntyre
- US National Park Service, Denali National Park and Preserve, 4175 Geist Road, Fairbanks, AK, 99709, USA
| | - Margaret C MacCluskie
- US National Park Service, Central Alaska Network, 4175 Geist Road, Fairbanks, AK, 99709, USA
| | - Melanie J Flamme
- US National Park Service, Yukon-Charley Rivers Preserve and Gates of the Arctic National Park and Preserve, 4175 Geist Road, Fairbanks, AK, 99709, USA
| |
Collapse
|
18
|
Soininen EM, Hamel S, Yoccoz NG. Importance of study design and robust analyses in ecology – what is the evidence for silica–vole interactions? Funct Ecol 2017. [DOI: 10.1111/1365-2435.12830] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Sandra Hamel
- UiT ‐ The Arctic University of Norway NO‐9037 Tromsø Norway
| | | |
Collapse
|
19
|
McLarnon E, McQueen-Mason S, Lenk I, Hartley SE. Evidence for Active Uptake and Deposition of Si-based Defenses in Tall Fescue. FRONTIERS IN PLANT SCIENCE 2017; 8:1199. [PMID: 28769939 PMCID: PMC5513917 DOI: 10.3389/fpls.2017.01199] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/26/2017] [Indexed: 05/06/2023]
Abstract
Silicon (Si) is taken up from the soil as monosilicic acid by plant roots, transported to leaves and deposited as phytoliths, amorphous silica (SiO2) bodies, which are a key component of anti-herbivore defense in grasses. Silicon transporters have been identified in many plant species, but the mechanisms underpinning Si transport remain poorly understood. Specifically, the extent to which Si uptake is a passive process, driven primarily by transpiration, or has both passive and active components remains disputed. Increases in foliar Si concentration following herbivory suggest plants may exercise some control over Si uptake and distribution. In order to investigate passive and active controls on Si accumulation, we examined both genetic and environmental influences on Si accumulation in the forage grass Festuca arundinacea. We studied three F. arundinacea varieties that differ in the levels of Si they accumulate. Varieties not only differed in Si concentration, but also in increases in Si accumulation in response to leaf damage. The varietal differences in Si concentration generally reflected differences in stomatal density and stomatal conductance, suggesting passive, transpiration-mediated mechanisms underpin these differences. Bagging plants after damage was employed to minimize differences in stomatal conductance between varieties and in response to damage. This treatment eliminated constitutive differences in leaf Si levels, but did not impair the damage-induced increases in Si uptake: damaged, bagged plants still had more leaf Si than undamaged, bagged plants in all three varieties. Preliminary differential gene expression analysis revealed that the active Si transporter Lsi2 was highly expressed in damaged unbagged plants compared with undamaged unbagged plants, suggesting damage-induced Si defenses are regulated at gene level. Our findings suggest that although differences in transpiration may be partially responsible for varietal differences in Si uptake, they cannot explain damage-induced increases in Si uptake and deposition, suggesting that wounding causes changes in Si uptake, distribution and deposition that likely involve active processes and changes in gene expression.
Collapse
Affiliation(s)
- Emma McLarnon
- Department of Biology, University of YorkYork, United Kingdom
| | | | | | | |
Collapse
|
20
|
|
21
|
Cooke J, DeGabriel JL, Hartley SE. The functional ecology of plant silicon: geoscience to genes. Funct Ecol 2016. [DOI: 10.1111/1365-2435.12711] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Julia Cooke
- Department of Earth, Environment and Ecosystems The Open University Walton Hall Milton Keynes MK7 6AA UK
| | - Jane L. DeGabriel
- Hawkesbury Institute for the Environment Western Sydney University Locked Bag 1797 Penrith New South Wales 2751 Australia
| | - Susan E. Hartley
- Department of Biology York Environmental Sustainability Institute University of York Heslington York YO10 5DD UK
| |
Collapse
|
22
|
Affiliation(s)
- Susan E. Hartley
- Department of Biology York Environmental Sustainability Institute University of York Heslington York YO10 5DD UK
| | - Jane L. DeGabriel
- Hawkesbury Institute for the Environment Western Sydney University Locked Bag 1797 Penrith New South Wales2751 Australia
| |
Collapse
|
23
|
Radchuk V, Ims RA, Andreassen HP. From individuals to population cycles: the role of extrinsic and intrinsic factors in rodent populations. Ecology 2016; 97:720-32. [DOI: 10.1890/15-0756.1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Viktoriia Radchuk
- Faculty of Applied ecology and Agricultural sciences Hedmark University College Campus Evenstad NO‐2480 Koppang Norway
| | - Rolf A. Ims
- Department of Arctic and Marine Biology The Arctic University of Norway NO‐9037 Tromsø Norway
| | - Harry P. Andreassen
- Faculty of Applied ecology and Agricultural sciences Hedmark University College Campus Evenstad NO‐2480 Koppang Norway
| |
Collapse
|
24
|
Calandra I, Zub K, Szafrańska PA, Zalewski A, Merceron G. Silicon-based plant defences, tooth wear and voles. J Exp Biol 2016; 219:501-7. [DOI: 10.1242/jeb.134890] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Plant–herbivore interactions are hypothesized to drive vole population cycles through the grazing-induced production of phytoliths in leaves. Phytoliths act as mechanical defences because they deter herbivory and lower growth rates in mammals. However, how phytoliths impair herbivore performance is still unknown. Here, we tested whether the amount of phytoliths changes tooth wear patterns. If confirmed, abrasion from phytoliths could play a role in population crashes. We applied dental microwear texture analysis (DMTA) to laboratory and wild voles. Lab voles were fed two pelleted diets with differing amounts of silicon, which produced similar dental textures. This was most probably due to the loss of food mechanical properties through pelletization and/or the small difference in silicon concentration between diets. Wild voles were trapped in Poland during spring and summer, and every year across a population cycle. In spring, voles feed on silica-rich monocotyledons, while in the summer they also include silica-depleted dicotyledons. This was reflected in the results; the amount of silica therefore leaves a traceable record in the dental microwear texture of voles. Furthermore, voles from different phases of population cycles have different microwear textures. We tentatively propose that these differences result from grazing-induced phytolith concentrations. We hypothesize that the high amount of phytoliths in response to intense grazing in peak years may result in malocclusion and other dental abnormalities, which would explain how these silicon-based plant defences help provoke population crashes. DMTA could then be used to reconstruct vole population dynamics using teeth from pellets or palaeontological material.
Collapse
Affiliation(s)
- Ivan Calandra
- GEGENAA – EA 3795, Université de Reims Champagne-Ardenne, 51100 Reims, France
| | - Karol Zub
- Mammal Research Institute, Polish Academy of Sciences, 17-230 Białowiez˙a, Poland
| | | | - Andrzej Zalewski
- Mammal Research Institute, Polish Academy of Sciences, 17-230 Białowiez˙a, Poland
| | - Gildas Merceron
- iPHEP UMR 7262, CNRS & Université de Poitiers, 86073 Poitiers, France
| |
Collapse
|
25
|
Reynolds OL, Padula MP, Zeng R, Gurr GM. Silicon: Potential to Promote Direct and Indirect Effects on Plant Defense Against Arthropod Pests in Agriculture. FRONTIERS IN PLANT SCIENCE 2016; 7:744. [PMID: 27379104 PMCID: PMC4904004 DOI: 10.3389/fpls.2016.00744] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/17/2016] [Indexed: 05/18/2023]
Abstract
Silicon has generally not been considered essential for plant growth, although it is well recognized that many plants, particularly Poaceae, have substantial plant tissue concentrations of this element. Recently, however, the International Plant Nutrition Institute [IPNI] (2015), Georgia, USA has listed it as a "beneficial substance". This reflects that numerous studies have now established that silicon may alleviate both biotic and abiotic stress. This paper explores the existing knowledge and recent advances in elucidating the role of silicon in plant defense against biotic stress, particularly against arthropod pests in agriculture and attraction of beneficial insects. Silicon confers resistance to herbivores via two described mechanisms: physical and biochemical/molecular. Until recently, studies have mainly centered on two trophic levels; the herbivore and plant. However, several studies now describe tri-trophic effects involving silicon that operate by attracting predators or parasitoids to plants under herbivore attack. Indeed, it has been demonstrated that silicon-treated, arthropod-attacked plants display increased attractiveness to natural enemies, an effect that was reflected in elevated biological control in the field. The reported relationships between soluble silicon and the jasmonic acid (JA) defense pathway, and JA and herbivore-induced plant volatiles (HIPVs) suggest that soluble silicon may enhance the production of HIPVs. Further, it is feasible that silicon uptake may affect protein expression (or modify proteins structurally) so that they can produce additional, or modify, the HIPV profile of plants. Ultimately, understanding silicon under plant ecological, physiological, biochemical, and molecular contexts will assist in fully elucidating the mechanisms behind silicon and plant response to biotic stress at both the bi- and tri-trophic levels.
Collapse
Affiliation(s)
- Olivia L. Reynolds
- Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, FujianChina
- Graham Centre for Agricultural Innovation, New South Wales Department of Primary Industries, Menangle, NSWAustralia
- *Correspondence: Geoff M. Gurr, ; Olivia L. Reynolds,
| | - Matthew P. Padula
- Proteomics Core Facility, School of Life Sciences, University of Technology Sydney, Sydney, NSWAustralia
| | - Rensen Zeng
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou, FujianChina
| | - Geoff M. Gurr
- Institute of Applied Ecology, Fujian Agriculture and Forestry University, Fuzhou, FujianChina
- Graham Centre for Agricultural Innovation, Charles Sturt University, Orange, NSWAustralia
- *Correspondence: Geoff M. Gurr, ; Olivia L. Reynolds,
| |
Collapse
|
26
|
Anderson KE, Inouye BD, Underwood N. Can inducible resistance in plants cause herbivore aggregations? Spatial patterns in an inducible plant/herbivore model. Ecology 2015; 96:2758-70. [PMID: 26649396 DOI: 10.1890/14-1697.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Many theories regarding the evolution of inducible resistance in plants have an implicit spatial component, but most relevant population dynamic studies ignore spatial dynamics. We examined a spatially explicit model of plant inducible resistance and herbivore population dynamics to explore how realistic features of resistance and herbivore responses influence spatial patterning. Both transient and persistent spatial patterns developed in all models examined, where patterns manifested as wave-like aggregations of herbivores and variation in induction levels. Patterns arose when herbivores moved away from highly induced plants, there was a lag between damage and deployment of induced resistance, and the relationship between herbivore density and strength of the induction response had a sigmoid shape. These mechanisms influenced pattern formation regardless of the assumed functional relationship between resistance and herbivore recruitment and mortality. However, in models where induction affected herbivore mortality, large-scale herbivore population cycles driven by the mortality response often co-occurred with smaller scale spatial patterns driven by herbivore movement. When the mortality effect dominated, however, spatial pattern formation was completely replaced by spatially synchronized herbivore population cycles. Our results present a new type of ecological pattern formation driven by induced trait variation, consumer behavior, and time delays that has broad implications for the community and evolutionary ecology of plant defenses.
Collapse
|
27
|
Hartley SE. Round and round in cycles? Silicon‐based plant defences and vole population dynamics. Funct Ecol 2015. [DOI: 10.1111/1365-2435.12365] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
28
|
Hartley SE, Fitt RN, McLarnon EL, Wade RN. Defending the leaf surface: intra- and inter-specific differences in silicon deposition in grasses in response to damage and silicon supply. FRONTIERS IN PLANT SCIENCE 2015; 6:35. [PMID: 25717331 PMCID: PMC4324063 DOI: 10.3389/fpls.2015.00035] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/14/2015] [Indexed: 05/06/2023]
Abstract
Understanding interactions between grasses and their herbivores is central to the conservation of species-rich grasslands and the protection of our most important crops against pests. Grasses employ a range of defenses against their natural enemies; silicon-based defenses have been shown to be one of the most effective. Silicon (Si) is laid down on the leaf surface as spines and other sharp bodies, known as phytoliths, making grasses abrasive and their foliage indigestible to herbivores. Previous studies on Si defenses found that closely related species may have similar levels of Si in the leaves but differ markedly in abrasiveness. Here we show how the number, shape and distribution of Si-rich phytoliths and spines differ within and between different grass species and demonstrate that species also differ in their ability to change the deposition and distribution of these defenses in response to damage or increases in Si supply. Specifically, we tested the response of two genotypes of Festuca arundinacea known to differ in their surface texture and three different grass species (F. ovina, F. rubra, and Deschampsia cespitosa) differing in their abrasiveness to combined manipulation of leaf damage and Si supply. F. arundinacea plants with a harsh leaf surface had higher Si content and more spines on their leaf surface than soft varieties. F. ovina and D. cespitosa plants increased their leaf Si concentration and produced an increase in the number of leaf spines and phytoliths on the leaf surface in response to Si addition. F rubra also increased leaf Si content in response to treatments, particularly in damaged leaves, but did not deposit this in the form of spines or increased densities of phytoliths. We discuss how the form in which grasses deposit Si may affect their anti-herbivore characteristics and consider the ecological and agricultural implications of the differences in allocation to Si-based defenses between grass species.
Collapse
Affiliation(s)
- Sue E. Hartley
- *Correspondence: Sue E. Hartley, Department of Biology, University of York, Wentworth Way, Heslington, York YO10 5DD, UK e-mail:
| | | | | | | |
Collapse
|
29
|
Wieczorek M, Zub K, Szafrańska PA, Książek A, Konarzewski M. Plant–herbivore interactions: silicon concentration in tussock sedges and population dynamics of root voles. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12327] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Monika Wieczorek
- Mammal Research Institute Polish Academy of Sciences 17‐230 Białowieża Poland
| | - Karol Zub
- Mammal Research Institute Polish Academy of Sciences 17‐230 Białowieża Poland
| | | | - Aneta Książek
- Institute of Biology University of Białystok 15‐950 Białystok Poland
| | - Marek Konarzewski
- Institute of Biology University of Białystok 15‐950 Białystok Poland
| |
Collapse
|
30
|
Huitu O, Forbes KM, Helander M, Julkunen-Tiitto R, Lambin X, Saikkonen K, Stuart P, Sulkama S, Hartley S. Silicon, endophytes and secondary metabolites as grass defenses against mammalian herbivores. FRONTIERS IN PLANT SCIENCE 2014; 5:478. [PMID: 25278951 PMCID: PMC4166226 DOI: 10.3389/fpls.2014.00478] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 08/30/2014] [Indexed: 05/29/2023]
Abstract
Grasses have been considered to primarily employ tolerance in lieu of defense in mitigating damage caused by herbivory. Yet a number of mechanisms have been identified in grasses, which may deter feeding by grazers. These include enhanced silicon uptake, hosting of toxin-producing endophytic fungi and induction of secondary metabolites. While these mechanisms have been individually studied, their synergistic responses to grazing, as well as their effects on grazers, are poorly known. A field experiment was carried out in 5 × 5 m outdoor enclosures to quantify phytochemical changes of either endophyte-infected (E+) or endophyte-free (E-) meadow fescue (Schedonorus pratensis) in response to medium intensity (corresponding with densities of ca. 1200 voles/ha for 5 weeks during 3 months) or heavy intensity (ca. 1200 voles/ha for 8 weeks during 3 months) grazing by a mammalian herbivore, the field vole (Microtus agrestis). A laboratory experiment was then conducted to evaluate the effects of endophyte infection status and grazing history of the grass diet on vole performance. As predicted, grazing increased foliar silicon content, by up to 13%. Grazing also increased foliar levels of phosphorous and several phenolic compounds, most notably those of the flavonols isorhamnetin-diglycoside and rhamnetin derivative. Silicon concentrations were consistently circa 16% higher in E+ grasses than in E-grasses, at all levels of grazing. Similarly, concentrations of chlorogenic acid derivative were found to be consistently higher in E+ than in E- grasses. Female voles maintained on heavily grazed grasses suffered higher mortality rates in the laboratory than female voles fed ungrazed grass, regardless of endophyte infection status. Our results conclusively demonstrate that, in addition to tolerance, grasses employ multi-tiered, effective defenses against mammalian grazers.
Collapse
Affiliation(s)
- Otso Huitu
- Suonenjoki Research Unit, Finnish Forest Research InstituteSuonenjoki, Finland
| | - Kristian M. Forbes
- Suonenjoki Research Unit, Finnish Forest Research InstituteSuonenjoki, Finland
| | | | | | - Xavier Lambin
- School of Biological Sciences, University of AberdeenAberdeen, UK
| | - Kari Saikkonen
- Plant Protection, Agrifood Research FinlandJokioinen, Finland
| | - Peter Stuart
- Suonenjoki Research Unit, Finnish Forest Research InstituteSuonenjoki, Finland
| | - Sini Sulkama
- Suonenjoki Research Unit, Finnish Forest Research InstituteSuonenjoki, Finland
| | - Sue Hartley
- Department of Biology, University of YorkYork, UK
| |
Collapse
|
31
|
Katz O. Beyond grasses: the potential benefits of studying silicon accumulation in non-grass species. FRONTIERS IN PLANT SCIENCE 2014; 5:376. [PMID: 25132839 PMCID: PMC4116777 DOI: 10.3389/fpls.2014.00376] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 07/14/2014] [Indexed: 05/06/2023]
Affiliation(s)
- Ofir Katz
- Department of Geography and Environmental Development, Ben-Gurion University of the NegevBe'er-Sheva, Israel
| |
Collapse
|
32
|
He H, Veneklaas EJ, Kuo J, Lambers H. Physiological and ecological significance of biomineralization in plants. TRENDS IN PLANT SCIENCE 2014; 19:166-74. [PMID: 24291440 DOI: 10.1016/j.tplants.2013.11.002] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/31/2013] [Accepted: 11/04/2013] [Indexed: 05/24/2023]
Abstract
Biomineralization is widespread in the plant kingdom. The most common types of biominerals in plants are calcium oxalate crystals, calcium carbonate, and silica. Functions of biominerals may depend on their shape, size, abundance, placement, and chemical composition. In this review we highlight advances in understanding physiological and ecological significance of biomineralization in plants. We focus on the functions of biomineralization in regulating cytoplasmic free calcium levels, detoxifying aluminum and heavy metals, light gathering and scattering to optimize photosynthesis, aiding in pollen release, germination, and tube growth, the roles it plays in herbivore deterrence, biogeochemical cycling of carbon, calcium, and silicon, and sequestering atmospheric CO2.
Collapse
Affiliation(s)
- Honghua He
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China; School of Plant Biology, The University of Western Australia, Crawley (Perth), WA 6009, Australia.
| | - Erik J Veneklaas
- School of Plant Biology, The University of Western Australia, Crawley (Perth), WA 6009, Australia
| | - John Kuo
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley (Perth), WA 6009, Australia
| | - Hans Lambers
- School of Plant Biology, The University of Western Australia, Crawley (Perth), WA 6009, Australia
| |
Collapse
|
33
|
Quigley KM, Anderson TM. Leaf silica concentration in Serengeti grasses increases with watering but not clipping: insights from a common garden study and literature review. FRONTIERS IN PLANT SCIENCE 2014; 5:568. [PMID: 25374577 PMCID: PMC4204439 DOI: 10.3389/fpls.2014.00568] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/02/2014] [Indexed: 05/23/2023]
Abstract
Grasses (Poaceae) lack the complex biochemical pathways and structural defenses employed by other plant families; instead they deposit microscopic silica (SiO2) granules in their leaf blades (i.e., phytoliths) as a putative defense strategy. Silica accumulation in grasses has generally been considered an inducible defense; other research suggests silica accumulation occurs by passive diffusion and should therefore be closely coupled with whole plant transpiration. We tested the hypothesis that grasses increase leaf silica concentration in response to artificial defoliation in a common garden study in the Serengeti ecosystem of East Africa. Additionally, a watering treatment tested the alternative hypothesis that leaf silica was largely driven by plant water status. Leaf silica content of two dominant C4 Serengeti grass species, Themeda triandra and Digitaria macroblephara, was quantified after a 10-month clipping × water experiment in which defoliation occurred approximately every 2 months and supplementary water was added every 2 weeks. Themeda had greater silica content than Digitaria, and Themeda also varied in foliar silica content according to collection site. Clipping had no significant effect on leaf silica in either species and watering significantly increased silica content of the dominant tall grass species, Themeda, but not the lawn species, Digitaria. Our data, and those collected as part of a supplementary literature review, suggest that silicon induction responses are contingent upon a combination of plant identity (i.e., species, genotype, life history limitations) and environmental factors (i.e., precipitation, soil nutrients, grazing intensity). Specifically, we propose that an interaction between plant functional type and water balance plays an especially important role in determining silica uptake and accumulation.
Collapse
Affiliation(s)
- Kathleen M. Quigley
- *Correspondence: Kathleen M. Quigley, Department of Biology, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27109, USA e-mail:
| | | |
Collapse
|
34
|
DeGabriel JL, Moore BD, Felton AM, Ganzhorn JU, Stolter C, Wallis IR, Johnson CN, Foley WJ. Translating nutritional ecology from the laboratory to the field: milestones in linking plant chemistry to population regulation in mammalian browsers. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2013.00727.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
35
|
Experimental evidence that livestock grazing intensity affects cyclic vole population regulation processes. POPUL ECOL 2013. [DOI: 10.1007/s10144-013-0398-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
36
|
Absolute stability and dynamical stabilisation in predator-prey systems. J Math Biol 2013; 68:1403-21. [PMID: 23571604 DOI: 10.1007/s00285-013-0672-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2012] [Revised: 03/08/2013] [Indexed: 10/27/2022]
Abstract
Many ecological systems exhibit multi-year cycles. In such systems, invasions have a complicated spatiotemporal structure. In particular, it is common for unstable steady states to exist as long-term transients behind the invasion front, a phenomenon known as dynamical stabilisation. We combine absolute stability theory and computation to predict how the width of the stabilised region depends on parameter values. We develop our calculations in the context of a model for a cyclic predator-prey system, in which the invasion front and spatiotemporal oscillations of predators and prey are separated by a region in which the coexistence steady state is dynamically stabilised.
Collapse
|
37
|
Andreassen HP, Glorvigen P, Rémy A, Ims RA. New views on how population-intrinsic and community-extrinsic processes interact during the vole population cycles. OIKOS 2013. [DOI: 10.1111/j.1600-0706.2012.00238.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
38
|
Reynolds JJH, Sherratt JA, White A, Lambin X. A comparison of the dynamical impact of seasonal mechanisms in a herbivore–plant defence system. THEOR ECOL-NETH 2012. [DOI: 10.1007/s12080-012-0173-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|