Nejvíce citovaný článek - PubMed ID 18523810
Differences in AM fungal root colonization between populations of perennial Aster species have genetic reasons
BACKGROUND: Despite many studies on the importance of competition and plants' associations with mutualists and pathogens on plant performance and community organization, the joint effects of these two factors remain largely unexplored. Even less is known about how these joint effects vary through a plant's life in different environmental conditions and how they contribute to the long-term coexistence of species. METHODS: We investigated the role of plant-soil feedback (PSF) in intra- and interspecific competition, using two co-occurring dry grassland species as models. A two-phase PSF experiment was used. In the first phase, soil was conditioned by the two plant species. In the second, we assessed the effect of soil conditioning, competition and drought stress on seedling establishment, plant growth in the first and second vegetation season, and fruit production. We also estimated effects of different treatments on overall population growth rates and predicted the species' potential coexistence. RESULTS: Soil conditioning played a more important role in the early stages of the plants' life (seedling establishment and early growth) than competition. Specifically, we found strong negative intraspecific PSF for biomass production in the first year in both species. Although the effects of soil conditioning persisted in later stages of plant's life, competition and drought stress became more important. Surprisingly, models predicting species coexistence contrasted with the effects on individual life stages, showing that our model species benefit from their self-conditioned soil in the long run. CONCLUSIONS: We provide evidence that the effects of PSF vary through plants' life stages. Our study suggests that we cannot easily predict the effects of soil conditioning on long-term coexistence of species using data only on performance at a single time as commonly done in PSF studies. We also show the importance of using as realistic environmental conditions as possible (such as drought stress experienced in dry grasslands) to draw reasonable conclusions on species coexistence.
- Klíčová slova
- Bromus erectus, Inula salicina, Janzen–Connell hypothesis, Plant–soil (below-ground) interactions, coexistence, germination, moisture treatment, population dynamics, population growth rate, target–neighbour design,
- MeSH
- půda * MeSH
- půdní mikrobiologie MeSH
- rostliny * MeSH
- semenáček MeSH
- vývoj rostlin MeSH
- zpětná vazba MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- půda * MeSH
After abandonment of agricultural fields, some grassland plant species colonize these sites with a frequency equivalent to dry grasslands (generalists) while others are missing or underrepresented in abandoned fields (specialists). We aimed to understand the inability of specialists to spread on abandoned fields by exploring whether performance of generalists and specialists depended on soil abiotic and/or biotic legacy. We performed a greenhouse experiment with 12 species, six specialists and six generalists. The plants were grown in sterile soil from dry grassland or abandoned field inoculated with microbial communities from one or the other site. Plant growth, abundance of mycorrhizal structures and plant response to inoculation were evaluated. We focused on arbuscular mycorrhizal fungi (AMF), one of the most important parts of soil communities affecting plant performance. The abandoned field soil negatively affected plant growth, but positively affected plant response to inoculation. The AMF community from both sites differed in infectivity and taxa frequencies. The lower AMF taxa frequency in the dry grassland soil suggested a lack of functional complementarity. Despite the fact that dry grassland AMF produced more arbuscules, the dry grassland inoculum did not improve phosphorus nutrition of specialists contrary to the abandoned field inoculum. Inoculum origin did not affect phosphorus nutrition of generalists. The lower effectiveness of the dry grassland microbial community toward plant performance excludes its inoculation in the abandoned field soil as a solution to allow settlement of specialists. Still, the distinct response of specialists and generalists to inoculation suggested that they differ in AMF responsiveness.
- Klíčová slova
- Fungal structures, Mycorrhizal response, Native AMF, Soil biota, Soil legacy,
- MeSH
- houby MeSH
- kořeny rostlin MeSH
- mikrobiota * MeSH
- mykorhiza * MeSH
- pastviny MeSH
- půda MeSH
- půdní mikrobiologie MeSH
- vývoj rostlin MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- půda MeSH
Plant-soil feedback (PSF) is a fundamental mechanism explaining plant community composition. Two-phase experiments, i.e., conditioning and feedback, represent a common methodology to study PSF. The duration of the conditioning phase varies among studies and the PSF observed is often explained by its biotic component. Little is known about the temporal variation of PSF and its abiotic component. As early life stages are crucial for plant establishment, we grew Rorippa austriaca in soil conditioned over 2, 4, 6 or 8 weeks by a conspecific or a co-occurring species, Agrostis capillaris. For each conditioning duration, we analysed the soil chemical properties and the direction and intensity of intra- or inter-specific feedbacks. With increasing duration, the negative intra- and inter-specific feedbacks became stronger and weaker, respectively. The inter-specific feedback was more negative than the intra-specific feedback at 2 weeks and this reversed thereafter. The Mg content decreased with conditioning duration whatever the conditioning species was. With increasing duration, conditioning by R. austriaca strongly decreased pH, while A. capillaris did not affect pH. The K and P contents were not affected by the conditioning duration and were higher in R. austriaca soil than in A. capillaris soil. Our results suggest that not only conditioning species but also duration of conditioning phase may affect the magnitude of PSF. The changes in soil chemical properties linked to the conditioning species or the conditioning phase duration may drive the feedbacks by affecting plant growth directly or via the interacting microbial communities.
- Klíčová slova
- Brassicaceae, Conditioning, Native species, Negative feedback, Plant-soil feedback indices,
- MeSH
- půda * MeSH
- půdní mikrobiologie MeSH
- rostliny * MeSH
- vývoj rostlin MeSH
- zpětná vazba MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- půda * MeSH
BACKGROUND: The importance of soil biota in the composition of mature plant communities is commonly acknowledged. In contrast, the role of soil biota in the early establishment of new plant communities and their relative importance for soil abiotic conditions are still poorly understood. AIMS AND METHODS: The aim of this study was to understand the effects of soil origin and soil fungal communities on the composition of a newly established dry grassland plant community. We used soil from two different origins (dry grassland and abandoned field) with different pH and nutrient and mineral content. Grassland microcosms were established by sowing seeds of 54 species of dry grassland plants into the studied soils. To suppress soil fungi, half of the pots were regularly treated with fungicide. In this way, we studied the independent and combined effects of soil origin and soil community on the establishment of dry grassland communities. KEY RESULTS: The effect of suppressing the soil fungal community on the richness and composition of the plant communities was much stronger than the effect of soil origin. Contrary to our expectations, the effects of these two factors were largely additive, indicating the same degree of importance of soil fungal communities in the establishment of species-rich plant communities in the soils from both origins. The negative effect of suppressing soil fungi on species richness, however, occurred later in the soil from the abandoned field than in the soil from the grassland. This result likely occurred because the negative effects of the suppression of fungi in the field soil were caused mainly by changes in plant community composition and increased competition. In contrast, in the grassland soil, the absence of soil fungi was limiting for plants already at the early stages of their establishment, i.e., in the phases of germination and early recruitment. While fungicide affects not only arbuscular mycorrhizal fungi but also other biota, our data indicate that changes in the AMF communities are the most likely drivers of the observed changes. The effects of other soil biota, however, cannot be fully excluded. CONCLUSIONS: These results suggest that the availability of soil fungi may not be the most important limiting factor for the establishment of grassland species in abandoned fields if we manage to reduce the intensity of competition at these sites e.g., by mowing or grazing.
- MeSH
- mikrobiální společenstva fyziologie MeSH
- mykorhiza fyziologie MeSH
- pastviny * MeSH
- půdní mikrobiologie * MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: Field translocation experiments (i.e., the introduction of seeds or seedlings of different species into different localities) are commonly used to study habitat associations of species, as well as factors limiting species distributions and local abundances. Species planted or sown in sites where they naturally occur are expected to perform better or equally well compared to sites at which they do not occur or are rare. This, however, contrasts with the predictions of the Janzen-Connell hypothesis and commonly reported intraspecific negative plant-soil feedback. The few previous studies indicating poorer performance of plants at sites where they naturally occur did not explore the mechanisms behind this pattern. AIMS AND METHODS: In this study, we used field translocation experiments established using both seeds and seedlings to study the determinants of local abundance of four dominant species in grasslands. To explore the possible effects of intraspecific negative plant-soil feedback on our results, we tested the effect of local species abundance on the performance of the plants in the field experiment. In addition, we set up a garden experiment to explore the intensity of intraspecific as well as interspecific feedback between the dominants used in the experiment. KEY RESULTS: In some cases, the distribution and local abundances of the species were partly driven by habitat conditions at the sites, and species performed better at their own sites. However, the prevailing pattern was that the local dominants performed worse at sites where they naturally occur than at any other sites. Moreover, the success of plants in the field experiment was lower in the case of higher intraspecific abundance prior to experimental setup. In the garden feedback experiment, two of the species performed significantly worse in soils conditioned by their species than in soils conditioned by the other species. In addition, the performance of the plants was significantly correlated between the two experiments, suggesting that plant-soil feedback is a likely explanation of the patterns observed in the field. CONCLUSIONS: All of the results indicate that intraspecific negative plant-soil feedback, either biotic or abiotic, may be a key factor determining the performance of the plants in our field translocation experiment. The possible effects of negative feedback should thus be considered when evaluating results of translocation experiments in future studies.
- MeSH
- ekosystém * MeSH
- pastviny MeSH
- půda * chemie MeSH
- rostliny * MeSH
- semenáček MeSH
- zahrady MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- půda * MeSH
At present, there is no relevant information on arbuscular mycorrhiza and the effect of the symbiosis on the growth of wild populations of cyclamens. To fill this gap, two populations of Cyclamen purpurascens subsp. immaculatum, endemic in Nízke Tatry (NT) mountains and Veľká Fatra (VF) mountains, Slovakia, were studied in situ as well as in a greenhouse pot experiment. For both populations, mycorrhizal root colonization of native plants was assessed, and mycorrhizal inoculation potential (MIP) of the soils at the two sites was determined in 3 consecutive years. In the greenhouse experiment, the growth response of cyclamens to cross-inoculation with arbuscular mycorrhizal fungi (AMF) was tested: plants from both sites were grown in their native soils and inoculated with a Septoglomus constrictum isolate originating either from the same or from the other plant locality. Although the MIP of soil at the NT site was significantly higher than at the VF site, the level of AMF root colonization of C. purpurascens subsp. immaculatum plants in the field did not significantly differ between the two localities. In the greenhouse experiment, inoculation with AMF generally accelerated cyclamen growth and significantly increased all growth parameters (shoot dry weight, leaf number and area, number of flowers, tuber, and root dry weight) and P uptake. The two populations of C. purpurascens subsp. immaculatum grown in their native soils, however, differed in their response to inoculation. The mycorrhizal growth response of NT plants was one-order higher compared to VF plants, and all their measured growth parameters were stimulated regardless of the fungal isolates' origin. In the VF plants, only the non-native (NT originating) isolate showed a significant positive effect on several growth traits. It can be concluded that mycorrhiza significantly increased fitness of C. purpurascens subsp. immaculatum, despite the differences between plant populations, implying that AMF symbionts should be taken into account in conservation programs of this endemic plant.
- Klíčová slova
- Growth response, Inoculation, Root colonization, Septoglomus constrictum, Wild cyclamens,
- MeSH
- Cyclamen růst a vývoj mikrobiologie MeSH
- fylogeneze MeSH
- kořeny rostlin mikrobiologie MeSH
- mykorhiza genetika růst a vývoj izolace a purifikace fyziologie MeSH
- půdní mikrobiologie MeSH
- symbióza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Slovenská republika MeSH
Due to increased levels of heterozygosity, polyploids are expected to have a greater ability to adapt to different environments than their diploid ancestors. While this theoretical pattern has been suggested repeatedly, studies comparing adaptability to changing conditions in diploids and polyploids are rare. The aim of the study was to determine the importance of environmental conditions of origin as well as target conditions on performance of two Anthericum species, allotetraploid A. liliago and diploid A. ramosum and to explore whether the two species differ in the ability to adapt to these environmental conditions. Specifically, we performed a common garden experiment using soil from 6 localities within the species' natural range, and we simulated the forest and open environments in which they might occur. We compared the performance of diploid A. ramosum and allotetraploid A. liliago originating from different locations in the different soils. The performance of the two species was not affected by simulated shading but differed strongly between the different target soils. Growth of the tetraploids was not affected by the origin of the plants. In contrast, diploids from the most nutrient poor soil performed best in the richest soil, indicating that diploids from deprived environments have an increased ability to acquire nutrients when available. They are thus able to profit from transfer to novel nutrient rich environments. Therefore, the results of the study did not support the general expectation that the polyploids should have a greater ability than the diploids to adapt to a wide range of conditions. In contrast, the results are in line with the observation that diploids occupy a wider range of environments than the allotetraploids in our system.
- MeSH
- diploidie MeSH
- ekosystém MeSH
- fyziologická adaptace * MeSH
- liliovité klasifikace genetika fyziologie MeSH
- polyploidie MeSH
- půda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- půda MeSH
Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies may increase our understanding of the mechanisms by which plants adapt to their environment.
- MeSH
- aklimatizace fyziologie MeSH
- Aster fyziologie MeSH
- kořeny rostlin MeSH
- mykorhiza růst a vývoj MeSH
- půdní mikrobiologie MeSH
- symbióza fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
Arbuscular mycorrhizal fungi (AMF) are expected to be one of the key drivers determining the diversity of natural plant communities, especially in nutrient-poor and dry habitats. Several previous studies have explored the importance of AMF for the composition of plant communities in various types of habitats. Surprisingly, studies of the role of AMF in nutrient-poor dry grassland communities dominated by less mycotrophic plant species are still relatively rare. We present the results of a 3-year study in which a plant community in a species-rich dry grassland was subjected to the fungicide carbendazim to suppress AMF colonization. We tested the effect of the fungicide on the following parameters: the plant species composition; the number of plant species; the cover of the rare, highly mycorrhiza-dependent species Aster amellus; the cover of the dominant, less mycorrhiza-dependent species Brachypodium pinnatum; and the cover of graminoids and perennial forbs. In addition, we examined the mycorrhizal inoculation potential of the soil. We found that the suppression of AMF with fungicide resulted in substantial changes in plant species composition and significant decrease in species richness, the cover of A. amellus and the cover of perennial forbs. In contrast the species increasing their cover after fungicide application were graminoids--the C3 grasses B. pinnatum and Bromus erectus and the sedge Carex flacca. These species appear to be less mycorrhiza dependent. Moreover, due to their clonal growth and efficient nutrient usage, they are, most likely, better competitors than perennial forbs under fungicide application. Our results thus suggest that AMF are an essential part of the soil communities supporting a high diversity of plant species in species-rich dry grasslands in nutrient-poor habitats. The AMF are especially important for the maintenance of the populations of perennial forbs, many of which are rare and endangered in the area.
- MeSH
- biodiverzita MeSH
- ekosystém MeSH
- fyziologie rostlin * MeSH
- houby účinky léků fyziologie MeSH
- lipnicovité MeSH
- mykorhiza účinky léků fyziologie MeSH
- období sucha * MeSH
- průmyslové fungicidy farmakologie MeSH
- půda * chemie MeSH
- rostliny účinky léků mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- průmyslové fungicidy MeSH
- půda * MeSH
Successful establishment of plants is limited by both biotic and abiotic conditions and their interactions. Seedling establishment is also used as a direct measure of habitat suitability, but transient changes in vegetation might provide windows of opportunity allowing plant species to colonize sites which otherwise appear unsuitable. We aimed to study spatio-temporal variability in the effects of resident vegetation on establishment, growth and reproduction of dry grassland species in abandoned arable fields representing potentially suitable habitats. Seeds were sown in disturbed (bare of vegetation and roots) and undisturbed plots in three fields abandoned in the last 20 years. To assess the effects of temporal variation on plant establishment, we initiated our experiments in two years (2007 and 2008). Seventeen out of the 35 sown species flowered within two years after sowing, while three species completely failed to become established. The vegetation in the undisturbed plots facilitated seedling establishment only in the year with low spring precipitation, and the effect did not hold for all species. In contrast, growth and flowering rate were consistently much greater in the disturbed plots, but the effect size differed between the fields and years of sowing. We show that colonization is more successful when site opening by disturbance coincide with other suitable conditions such as weather or soil characteristics. Seasonal variability involved in our study emphasizes the necessity of temporal replication of sowing experiments. Studies assessing habitat suitability by seed sowing should either involve both vegetation removal treatments and untreated plots or follow the gradient of vegetation cover. We strongly recommend following the numbers of established individuals, their sizes and reproductive success when assessing habitat suitability by seed sowing since one can gain completely different results in different phases of plant life cycle.
- MeSH
- druhová specificita MeSH
- ekosystém MeSH
- květy růst a vývoj MeSH
- lipnicovité růst a vývoj MeSH
- Magnoliopsida růst a vývoj MeSH
- půda MeSH
- roční období MeSH
- semena rostlinná růst a vývoj MeSH
- semenáček růst a vývoj MeSH
- zemědělství MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Názvy látek
- půda MeSH