scholarly journals Interaction between plant genotype and the symbiosis with Epichloë fungal endophytes in seeds of red fescue (Festuca rubra)

2011 ◽  
Vol 62 (11) ◽  
pp. 1010 ◽  
Author(s):  
P. E. Gundel ◽  
I. Zabalgogeazcoa ◽  
B. R. Vázquez de Aldana
Keyword(s):  
Seed Germination ◽  
Fungal Endophytes ◽  
Germination Percentage ◽  
Fungal Endophyte ◽  
Festuca Rubra ◽  
Plant Genotype ◽  
Host Genotype ◽  
Natural Habitats ◽  
Incubation Condition ◽  
Seed Survival

In diverse natural habitats of Europe, plants of Festuca rubra are commonly infected by the fungal endophyte Epichloë festucae. Under several circumstances, the association between the grass and the fungus has been shown to be mutualistic. Here, we conducted an experiment to study the differences in seed germination and mortality between infected (E+) and endophyte-free plants (E–) at different temperatures (12 and 25°C) and water potentials (0 and –0.5 MPa). Three half-sib lines of F. rubra, each composed of E+ and E– seeds, and derived from infected plants from semiarid grasslands were used. Although the endophyte effect depended on the incubation condition, germination percentage was significantly greater for E– (52%) than for E+ seeds (41%). Seed germination was more inhibited by the low water potential (75 v. 24% for –0.5 and 0.0 MPa, respectively), than by the high temperature (64 v. 35% for 25 and 12°C, respectively). However, mortality was highly dependent on the interaction between plant genotype and endophyte, and between temperature and water condition. It is remarkable that while highly dependent on the host genotype, there was a clear effect of endophyte increasing seed survival, especially in those treatments that were unfavourable for germination. For example, in the more restrictive treatment (25°C and –0.5 MPa), seed survival was on average, 44 and 39% for E+ and E–, respectively. In general, the endophyte affected seed characteristics of F. rubra by reducing the percentage of germination, but simultaneously increasing seed survival.

Fungal endophytes of Festuca rubra increase in frequency following long-term exclusion of rabbits

Botany ◽  
2015 ◽  
Vol 93 (4) ◽  
pp. 233-241 ◽  
Author(s):  
James S. Santangelo ◽  
Nash E. Turley ◽  
Marc T.J. Johnson
Keyword(s):  
Plant Growth ◽  
Intraspecific Competition ◽  
Fungal Endophytes ◽  
Natural Populations ◽  
Fungal Endophyte ◽  
Festuca Rubra ◽  
Red Fescue ◽  
Grass Endophyte ◽  
Defensive Mutualism ◽  
Endophyte Infection

Plant – fungal endophyte interactions are common in nature and they can shape the ecology of plants. Vertically transmitted endophytes are hypothesized to serve as mutualists, protecting plants from herbivores. If this hypothesis is true, then we expect endophytes to be most abundant in the presence of herbivores and least abundant in their absence, assuming endophytes incur a cost to their host. We tested this prediction by studying the effects of intense rabbit (Oryctolagus cuniculus Linnaeus) grazing on grass–endophyte interactions at Silwood Park, UK. We examined seeds of red fescue (Festuca rubra L.) collected from 15 natural populations that were protected from rabbits for 0.3–21 years. Contrary to our prediction, the mean proportion of seeds with endophytes increased 1.84×, from 0.45 to 0.83, following 21 years of rabbit exclusion. To better understand the mechanisms driving this increase in frequency, we conducted a fully factorial greenhouse experiment where we manipulated the presence or absence of endophyte infection, intraspecific competition, and simulated grazing on F. rubra plants. In both damaged and undamaged treatments, infected plants produced approximately twice as much biomass as uninfected plants, and endophytes did not influence tolerance to herbivory. These results suggest that endophytes directly change plant growth but not compensatory responses to damage. In the absence of competitors, infected plants produced 2.17× more biomass than uninfected plants, whereas in the presence of competitors, infected plants produced only 1.55× more biomass than uninfected plants. This difference suggests that intraspecific competition might lessen the benefits of endophyte infection. Our results do not support the defensive mutualism hypothesis, but instead suggest that endophyte-induced plant growth is important in shaping the costs and benefits of endophytes in our system.

Fungal endophytes improve wheat seed germination under heat and drought stress

Botany ◽  
2012 ◽  
Vol 90 (2) ◽  
pp. 137-149 ◽  
Author(s):  
Michelle Hubbard ◽  
James Germida ◽  
Vladimir Vujanovic
Keyword(s):  
Drought Stress ◽  
Seed Germination ◽  
Life Stage ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Wheat Seed ◽  
Hydrothermal Time ◽  
Fresh Weight ◽  
First Time ◽  
Stressful Environments

Seed germination is a critical life stage for plants survival and timely seedling establishment especially in stressful environments. We hypothesized that fungal endophytes would improve wheat seed germination under heat and drought stress. The hydrothermal time (HTT) model of germination is a conceptual model useful for predicting the timing and energy of germination (EG) under a given set of conditions. The HTT and EG are applied, for the first time, to determine if one or more compatible endophytic fungi enhance heat or drought tolerance in wheat. Fungal endophytes tested dramatically increased the percent of germination, improved EG and HTT values, and diminished wheat susceptibility to heat and drought as measured by fresh weight of seedlings. When colonized by the most effective fungal endophyte, the values of the parameters tested in wheat seeds exposed to heat stress resembled those of unstressed seeds.

scholarly journals Fungal Endophyte Communities of Three Agricultural Important Grass Species Differ in Their Response Towards Management Regimes

2019 ◽  
Vol 7 (2) ◽  
pp. 37 ◽  
Author(s):  
Bernd Wemheuer ◽  
Torsten Thomas ◽  
Franziska Wemheuer
Keyword(s):  
Management Practices ◽  
Fungal Endophytes ◽  
Grassland Management ◽  
Fertilizer Application ◽  
Fungal Endophyte ◽  
Grass Species ◽  
Festuca Rubra ◽  
Health It ◽  
Aerial Parts ◽  
Dactylis Glomerata L

Despite the importance of endophytic fungi for plant health, it remains unclear how these fungi are influenced by grassland management practices. Here, we investigated the effect of fertilizer application and mowing frequency on fungal endophyte communities and their life strategies in aerial tissues of three agriculturally important grass species (Dactylis glomerata L., Festuca rubra L. and Lolium perenne L.) over two consecutive years. Our results showed that the management practices influenced fungal communities in the plant holobiont, but observed effects differed between grass species and sampling year. Phylogenetic diversity of fungal endophytes in D. glomerata was significantly affected by mowing frequency in 2010, whereas fertilizer application and the interaction of fertilization with mowing frequency had a significant impact on community composition of L. perenne in 2010 and 2011, respectively. Taken together, our research provides a basis for future studies on responses of fungal endophytes towards management practices. To the best of our knowledge, this is the first study simultaneously assessing fungal endophyte communities in aerial parts of three agriculturally important grass species over two consecutive years.

scholarly journals Effect of H2O-Based Low-Pressure Plasma (LPP) Treatment on the Germination of Bambara Groundnut Seeds

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 338
Author(s):  
Naeem Ahmed ◽  
Asad Masood ◽  
Kim S. Siow ◽  
M. F. Mohd Razip Wee ◽  
Rahmat Zaki Auliya ◽  
...  
Keyword(s):  
Food Security ◽  
Seed Germination ◽  
Chemical Modification ◽  
Low Pressure ◽  
Germination Percentage ◽  
Bambara Groundnut ◽  
Pressure Plasma ◽  
Low Pressure Plasma ◽  
Amine Groups

In general, seed germination is improved by low-pressure plasma (LPP) treatment using precursors such as air, nitrogen, argon, or water (H2O). Here, H2O-based LPP treatment using the optimized parameters of 10 W and 10 s improves the germination of Bambara groundnut seeds by 22%. LPP increases the wettability and roughness of the seed hilum while oxidizing the surface with carboxyl and amine groups. In this H2O-based treatment of Bambara groundnut seeds, combinatory etching and chemical modification facilitated the imbibition process and increased the germination percentage. The success of this method has the potential to be scaled up to solve food security with seeds otherwise facing germination-related issues.

scholarly journals Asymbiotic germination of Vanilla planifolia in relation to the timing of seed collection and seed pretreatments

2021 ◽  
Vol 62 (1) ◽  
Author(s):  
Chih-Hsin Yeh ◽  
Kai-Yi Chen ◽  
Yung-I. Lee
Keyword(s):  
Seed Germination ◽  
Seed Development ◽  
Seed Coat ◽  
Germination Percentage ◽  
Vanilla Planifolia ◽  
Outermost Layer ◽  
Seed Collection ◽  
Seed Pretreatment ◽  
Immature Seeds ◽  
Mature Seeds

Abstract Background Vanilla planifolia is an important tropical orchid for production of natural vanilla flavor. Traditionally, V. planifolia is propagated by stem cuttings, which produces identical genotype that are sensitive to virulent pathogens. However, propagation with seed germination of V. planifolia is intricate and unstable because the seed coat is extremely hard with strong hydrophobic nature. A better understanding of seed development, especially the formation of impermeable seed coat would provide insights into seed propagation and conservation of genetic resources of Vanilla. Results We found that soaking mature seeds in 4% sodium hypochlorite solution from 75 to 90 min significantly increased germination. For the culture of immature seeds, the seed collection at 45 days after pollination (DAP) had the highest germination percentage. We then investigated the anatomical features during seed development that associated with the effect of seed pretreatment on raising seed germination percentage. The 45-DAP immature seeds have developed globular embryos and the thickened non-lignified cell wall at the outermost layer of the outer seed coat. Seeds at 60 DAP and subsequent stages germinated poorly. As the seed approached maturity, the cell wall of the outermost layer of the outer seed coat became lignified and finally compressed into a thick envelope at maturity. On toluidine blue O staining, the wall of outer seed coat stained greenish blue, indicating the presence of phenolic compounds. As well, on Nile red staining, a cuticular substance was detected in the surface wall of the embryo proper and the innermost wall of the inner seed coat. Conclusion We report a reliable protocol for seed pretreatment of mature seeds and for immature seeds culture based on a defined time schedule of V. plantifolia seed development. The window for successful germination of culturing immature seed was short. The quick accumulation of lignin, phenolics and/or phytomelanins in the seed coat may seriously inhibit seed germination after 45 DAP. As seeds matured, the thickened and lignified seed coat formed an impermeable envelope surrounding the embryo, which may play an important role in inducing dormancy. Further studies covering different maturity of green capsules are required to understand the optimal seed maturity and germination of seeds.

scholarly journals Tree Diversity Reduces Fungal Endophyte Richness and Diversity in a Large-Scale Temperate Forest Experiment

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 234 ◽  
Author(s):  
Eric A. Griffin ◽  
Joshua G. Harrison ◽  
Melissa K. McCormick ◽  
Karin T. Burghardt ◽  
John D. Parker
Keyword(s):  
Phylogenetic Diversity ◽  
Large Scale ◽  
High Throughput Sequencing ◽  
Spatial Scales ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Tree Diversity ◽  
Trophic Levels ◽  
Community Diversity ◽  
And Function

Although decades of research have typically demonstrated a positive correlation between biodiversity of primary producers and associated trophic levels, the ecological drivers of this association are poorly understood. Recent evidence suggests that the plant microbiome, or the fungi and bacteria found on and inside plant hosts, may be cryptic yet important drivers of important processes, including primary production and trophic interactions. Here, using high-throughput sequencing, we characterized foliar fungal community diversity, composition, and function from 15 broadleaved tree species (N = 545) in a recently established, large-scale temperate tree diversity experiment using over 17,000 seedlings. Specifically, we tested whether increases in tree richness and phylogenetic diversity would increase fungal endophyte diversity (the “Diversity Begets Diversity” hypothesis), as well as alter community composition (the “Tree Diversity–Endophyte Community” hypothesis) and function (the “Tree Diversity–Endophyte Function” hypothesis) at different spatial scales. We demonstrated that increasing tree richness and phylogenetic diversity decreased fungal species and functional guild richness and diversity, including pathogens, saprotrophs, and parasites, within the first three years of a forest diversity experiment. These patterns were consistent at the neighborhood and tree plot scale. Our results suggest that fungal endophytes, unlike other trophic levels (e.g., herbivores as well as epiphytic bacteria), respond negatively to increasing plant diversity.

scholarly journals Effect of Environmental Factors on the Germination and Emergence of Drunken Horse Grass (Achnatherum inebrians)

Weed Science ◽  
2020 ◽  
pp. 1-29
Author(s):  
Yonghuan Yue ◽  
Guili Jin ◽  
Weihua Lu ◽  
Ke Gong ◽  
Wanqiang Han ◽  
...  
Keyword(s):  
Seed Germination ◽  
Environmental Factors ◽  
Abiotic Factors ◽  
Seedling Emergence ◽  
Management Strategies ◽  
Germination Percentage ◽  
Western China ◽  
Burial Depth ◽  
Achnatherum Inebrians ◽  
Water Ph

Abstract Drunken horse grass [Achnatherum inebrians (Hance) Keng] is a perennial poisonous weed in western China. A comprehensive understanding of the ecological response of A. inebrians germination to environmental factors would facilitate the formulation of better management strategies for this weed. Experiments were conducted under laboratory conditions to assess the effects of various abiotic factors, including temperature, light, water, pH and burial depth, on the seed germination and seedling emergence of A. inebrians. The seeds germinated at constant temperatures of 15, 20, 25, 30, 35°C and in alternating-temperature regimes of 15/5, 20/10, 25/15, 30/20, 35/25, 40/30°C, and the seed germination percentages under constant and alternating temperatures ranged from 51% to 94% and 15% to 93%, respectively. Maximum germination occurred at a constant temperature of 25°C, and germination was prevented at 45/35°C. Light did not appear to affect seed germination. The germination percentage of seeds was more than 75% in the pH range of 5 to 10, with the highest germination percentage at pH 6. The seeds germinated at osmotic potentials of 0 MPa to -1.0 MPa, but decreasing osmotic potential inhibited germination, with no germination at -1.2MPa. After 21 d of low osmotic stress, the seeds that did not germinate after rehydration had not lost their vitality. The seedling emergence percentage was highest (90%) when seeds were buried at 1 cm but declined with increasing burial depth and no emergence at 9 cm. Deep tillage may be effective in limiting the seed germination and emergence of this species. The results of this study provide useful information on the conditions necessary for A. inebrians germination and provide a theoretical basis for science-based prediction, prevention and control of this species.

The Effect of High Concentrations of Ethylene on Seed Germination of Douglas Fir (Pseudotsugamenziesii (Mirb.) Franco)

1975 ◽  
Vol 5 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Carey Borno ◽  
Iain E. P. Taylor
Keyword(s):  
Seed Germination ◽  
Germination Rate ◽  
Inhibitory Effect ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Control Treatment ◽  
Continuous Exposure ◽  
Short Term ◽  
Short Term Exposure ◽  
High Concentrations

Stratified, imbibed Douglas fir (Pseudotsugamenziesii (Mirb.) Franco) seeds were exposed to 100% ethylene for times between 0 and 366 h. Germination rate and germination percentage were increased by treatments up to 48 h. The 12-h treatment gave largest stimulation; 30% enhancement of final germination percentage over control. Treatment for 96 h caused increased germination rate for the first 5 days but reduced the germination percentage. Germinants were subject to continuous exposure to atmospheres containing 0.1 – 200 000 ppm ethylene in air, but it did not stimulate growth, and the gas was inhibitory above 100 ppm. Although some effects of high concentrations of ethylene may have been due to the lowering of oxygen supplies, this alone was insufficient to account for the full inhibitory effect. The mechanism of stimulation by short-term exposure to ethylene is discussed.

A light and electron microscope study of the fungal endophytes in the sporophyte and gametophyte of Lycopodium cernuum with observations on the gametophyte–sporophyte junction

1992 ◽  
Vol 70 (1) ◽  
pp. 58-72 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Roberto Ligrone
Keyword(s):  
Root Nodules ◽  
Fungal Endophytes ◽  
Fungal Endophyte ◽  
Peninsular Malaysia ◽  
Epidermal Cells ◽  
Host Cells ◽  
Wall Material ◽  
Intercellular Spaces ◽  
Host Cytoplasm ◽  
Fungal Associations

The ventral epidermal cells of the photosynthetic, surface-living gametophytes of Lycopodium cernuum, collected from moist shaded banks in Peninsular Malaysia, contain an aseptate fungus. In some cells the hyphae are thick walled and form coils encapsulated by a thin layer of host wall material. In others the fungus is thin walled and shows limited differentiation into larger trunk hyphae and arbuscules. The adjacent host cytoplasm, separated from the fungus by a granular interfacial matrix, contains numerous chloroplasts, mitochondria, and microtubules. The hyphae contact the substratum via the ventral walls of the epidermal cells and the rhizoids are free from infection. In the protocorm and root nodules, aseptate hyphae initially colonize mucilage-filled schizogenous intercellular spaces. Subsequent invasion of the host cells is associated with the development of massive overgrowths of host wall material. The fungal associations in L. cernuum share a mixture of attributes otherwise found in different angiosperm mycorrhizae and in mycotrophic relationships in liverworts. Wall ingrowths are present in both the gametophyte and sporophyte cells in the placenta of L. cernuum. The very limited development of the placenta, compared with L. appressum, certain bryophytes and ferns, the diminutive size, and early senescence of the gametophytes of L. cernuum are all linked to the presence of the protocorm. This massive absorptive organ, homologous to a foot, in terms of its position in sporophyte ontogeny, but external to the parent gametophyte, derives its nutrition partly from photosynthesis and partly from its fungal endophyte. Key words: chloroplasts, Lycopodium, mycorrhiza, pteridophytes, root nodules, symbiosis, transfer cells.

Factors affecting red-osier dogwood seed germination

1992 ◽  
Vol 70 (5) ◽  
pp. 1012-1016 ◽  
Author(s):  
S. N. Acharya ◽  
C. B. Chu ◽  
R. Hermesh ◽  
G. B. Schaalje
Keyword(s):  
Seed Germination ◽  
Germination Percentage ◽  
Collection Site ◽  
Moisture Condition ◽  
Seed Formation ◽  
Factors Affecting ◽  
Year Effect ◽  
Wide Range ◽  
Cornus Stolonifera ◽  
Moisture Conditions

Seeds from 55 populations of native Alberta red-osier dogwood (Cornus stolonifera Michx.) were collected over 2 years (1984 and 1985) to determine the range of variability for seed germination and the effect of ecoregion and moisture conditions in the collection sites on this trait. Each year the unscarified seeds were stored at 3 °C for 30 days, stratified at 3 °C for an additional 30 days and then incubated on an 8 h light: 16 h dark cycle at a temperature of 25:10 °C (light:dark) for germination. A wide range of germination percentages was observed among populations collected in any 1 year. However, the variability was not due to the ecoregion or moisture condition of the collection site. Germination percentage of populations collected in 1984 and 1985 formed five and seven groups, respectively. A study involving eight sites that were common to 1984, 1985, and 1986 revealed a significant effect of population on seed germination. This population effect was not obscured by the combined effects of year, precipitation, temperature, and seed size. The year effect was significant only when population was used as a covariate. Precipitation during seed formation significantly influenced germination performance even after adjustments were made for population and year. Seed germination in red-osier dogwood appears to be influenced by the population from which the seeds are collected and by yearly environmental fluctuations. Therefore, germination studies in this species must include seeds from diverse populations collected over several years. Key words: red-osier dogwood, Cornus stolonifera Michx., germination, population, environment.

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