scholarly journals Silicon Alters Leaf Surface Morphology and Suppresses Insect Herbivory in a Model Grass Species

Plants ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 643 ◽  
Author(s):  
Casey R. Hall ◽  
Vaibhav Dagg ◽  
Jamie M. Waterman ◽  
Scott N. Johnson
Keyword(s):  
Surface Morphology ◽  
Leaf Surface ◽  
Brachypodium Distachyon ◽  
Insect Herbivory ◽  
Matter Content ◽  
Acheta Domesticus ◽  
Grass Species ◽  
Dry Matter Content ◽  
Leaf Toughness ◽  
Model Grass

Grasses accumulate large amounts of silicon (Si) which is deposited in trichomes, specialised silica cells and cell walls. This may increase leaf toughness and reduce cell rupture, palatability and digestion. Few studies have measured leaf mechanical traits in response to Si, thus the effect of Si on herbivores can be difficult to disentangle from Si-induced changes in leaf surface morphology. We assessed the effects of Si on Brachypodium distachyon mechanical traits (specific leaf area (SLA), thickness, leaf dry matter content (LDMC), relative electrolyte leakage (REL)) and leaf surface morphology (macrohairs, prickle, silica and epidermal cells) and determined the effects of Si on the growth of two generalist insect herbivores (Helicoverpa armigera and Acheta domesticus). Si had no effect on leaf mechanical traits; however, Si changed leaf surface morphology: silica and prickle cells were on average 127% and 36% larger in Si supplemented plants, respectively. Prickle cell density was significantly reduced by Si, while macrohair density remained unchanged. Caterpillars were more negatively affected by Si compared to crickets, possibly due to the latter having a thicker and thus more protective gut lining. Our data show that Si acts as a direct defence against leaf-chewing insects by changing the morphology of specialised defence structures without altering leaf mechanical traits.

scholarly journals EFFICIENCY OF THE APPLICATION OF HORN-HOOFED CRUMB AND TREPEL UNDER ROW CROPS AND IN AFTEREFFECT ON BARLEY

2021 ◽  
Vol 16 (4) ◽  
pp. 27-32
Author(s):  
Ivan Eliseev ◽  
Lyudmila Eliseeva ◽  
Leonid Shashkarov
Keyword(s):  
Surface Area ◽  
Dry Matter ◽  
Leaf Surface ◽  
Matter Content ◽  
Nitrogen Fertilizers ◽  
Nitrate Content ◽  
Mineral Fertilizers ◽  
Dry Matter Content ◽  
Row Crops ◽  
Leaf Surface Area

The purpose of the work is to study the effectiveness of using horny hoofed crumbs from the waste of the meat processing industry as an organic fertilizer, in comparison with mineral nitrogen fertilizers and zeolite-containing trepel in the Chuvash Republic. The direct effect was determined on potatoes and fodder beets, the aftereffect was determined on spring barley. The soil of the experimental plot is light gray forest with a low (2.5 ... 2.6 %) humus content. The application of horn-hoof crumbs to potatoes and fodder beets at a rate of 430 kg/ha, equivalent to N60, together with phosphorus-potassium mineral fertilizers (P60K60), in terms of influence on crop yields, was not inferior to the effect of a complete mineral fertilizer at a rate of N60P60K60. In the variants with the introduction of horn-hoofed crumbs and phosphorus-potassium fertilizers, both independently and with the addition of zeolite-containing trepel at a rate of 2 t/ha, compared with the use of complete mineral fertilization, on average for 2012–2016. an increase in the biological activity of the soil was noted by 7.1 ... 11.0 %; in potato plantings, the leaf surface area increased by 7.0 ... 15.1 thousand m2/ha, the dry matter content in tubers - by 1.4 ... 2.5 %, their marketability - by 0.4 ... 0.7 %, the nitrate content decreased by 1.14 ... 1.45 %. In the crops of fodder beets, the leaf surface area of plants increased by 3.3 ... 5.0 thousand m2/ha, the dry matter content - by 0.8 ... 2.8 %, the concentration of nitrates - decreased by 43.9 ... 40.3 %. The coefficient of energy efficiency of the combined use of horn-hoofed crumb and trepel for row crops was at the level of 1.0. The aftereffect from their introduction was noted the next year when growing barley, the coefficient of bioenergy efficiency was 2.0 ... 2.2

Conserved microRNAs and their targets in model grass species Brachypodium distachyon

Planta ◽  
2009 ◽  
Vol 230 (4) ◽  
pp. 659-669 ◽  
Author(s):  
Turgay Unver ◽  
Hikmet Budak
Keyword(s):  
Brachypodium Distachyon ◽  
Grass Species ◽  
Model Grass

Is silicon a double-edged sword against insect herbivores? 

2021 ◽  
Author(s):  
Tarikul Islam ◽  
Ben D. Moore ◽  
Scott N. Johnson
Keyword(s):  
Natural Enemies ◽  
Brachypodium Distachyon ◽  
Insect Herbivory ◽  
The Body ◽  
Insect Herbivores ◽  
Plant Tolerance ◽  
Cascading Effects ◽  
Trade Offs ◽  
Model Grass ◽  
Humoral Responses

<p>In recent years, silicon (Si) has been increasingly linked to biotic stress management in plants including insect herbivory. The effectiveness of Si against chewing insects is now well recognized. Silicification of plant tissues makes them abrasive and tougher, reducing their masticability and digestibility to insect herbivores. This can cause mandibular wearing of chewers and affect their growth and feeding. Although there has been extensive research on the effects of Si on plant defences (i.e. antixenosis and antibiosis), it remains unclear how feeding on silicified plants affects insect defences to their natural enemies. Insect herbivores show morphological and behavioural defences when encountering predators and parasitoids. For example, lepidopteran larvae can regurgitate, twist the body, or even drop off the plants when attacked by natural enemies. Moreover, insects possess innate immunity (physiological defence) against the attackers, demonstrating cellular and humoral responses upon attack. Notably, there could be potential trade-offs between different defence and immunity traits. Given that feeding on Si-rich plants affects insect growth rates, this could impact their relative investment in different defences, thereby making insects more susceptible to their enemies. We are investigating the effects of Si on plant resistance and tolerance to herbivory and its cascading effects on insect defences to their enemies. We have been growing the model grass, <em>Brachypodium distachyon</em>, a high Si-accumulator, hydroponically with or without Si and examining the effects of Si against the global insect herbivore, <em>Helicoverpa armigera</em>. Our preliminary results suggest that Si supplementation enhances plant antixenotic and antibiotic traits and increases plant tolerance to herbivory. We are currently exploring insect defence and immunity traits when fed on silicified versus non-silicified plants. Our study would shed light on the impacts of Si on insects’ susceptibility to biocontrol agents and provide a better understanding of the effects of Si on insect-plant-natural enemy interactions.</p>

scholarly journals CG methylation covaries with differential gene expression between leaf and floral bud tissues of Brachypodium distachyon

2015 ◽  
Author(s):  
Kyria Roessler ◽  
Shohei Takuno ◽  
Brandon Gaut
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Sequence Data ◽  
Brachypodium Distachyon ◽  
Grass Species ◽  
Specific Gene ◽  
Specific Expression ◽  
Tissue Specific ◽  
Model Grass ◽  
Floral Bud

DNA methylation has the potential to influence plant growth and development through its influence on gene expression. To date, however, the evidence from plant systems is mixed as to whether patterns of DNA methylation vary significantly among tissues and, if so, whether these differences affect tissue-specific gene expression. To address these questions, we analyzed both bisulfite sequence (BSseq) and transcriptomic sequence data from three biological replicates of two tissues (leaf and floral bud) from the model grass species Brachypodium distachyon. Our first goal was to determine whether tissues were more differentiated in DNA methylation than explained by variation among biological replicates. Tissues were more differentiated than biological replicates, but the analysis of replicated data revealed high (>50%) false positive rates for the inference of differentially methylated sites (DMSs) and differentially methylated regions (DMRs). Comparing methylation to gene expression, we found that differential CG methylation consistently covaried negatively with gene expression, regardless as to whether methylation was within genes, within their promoters or even within their closest transposable element. The relationship between gene expression and either CHG or CHH methylation was less consistent. In total, CG methylation in promoters explained 9% of the variation in tissue-specific expression across genes, suggesting that CG methylation is a minor but appreciable factor in tissue differentiation.

scholarly journals Genetic and Methylome Variation in Turkish Brachypodium Distachyon Accessions Differentiate Two Geographically Distinct Subpopulations

2020 ◽  
Vol 21 (18) ◽  
pp. 6700
Author(s):  
Aleksandra Skalska ◽  
Christoph Stritt ◽  
Michele Wyler ◽  
Hefin W. Williams ◽  
Martin Vickers ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Brachypodium Distachyon ◽  
Growth Conditions ◽  
Grass Species ◽  
Niche Modelling ◽  
Climate Niche ◽  
Population Structure Analysis ◽  
Delayed Flowering ◽  
Model Grass ◽  
The Uk

Brachypodium distachyon (Brachypodium) is a non-domesticated model grass species that can be used to test if variation in genetic sequence or methylation are linked to environmental differences. To assess this, we collected seeds from 12 sites within five climatically distinct regions of Turkey. Seeds from each region were grown under standardized growth conditions in the UK to preserve methylated sequence variation. At six weeks following germination, leaves were sampled and assessed for genomic and DNA methylation variation. In a follow-up experiment, phenomic approaches were used to describe plant growth and drought responses. Genome sequencing and population structure analysis suggested three ancestral clusters across the Mediterranean, two of which were geographically separated in Turkey into coastal and central subpopulations. Phenotypic analyses showed that the coastal subpopulation tended to exhibit relatively delayed flowering and the central, increased drought tolerance as indicated by reduced yellowing. Genome-wide methylation analyses in GpC, CHG and CHH contexts also showed variation which aligned with the separation into coastal and central subpopulations. The climate niche modelling of both subpopulations showed a significant influence from the “Precipitation in the Driest Quarter” on the central subpopulation and “Temperature of the Coldest Month” on the coastal subpopulation. Our work demonstrates genetic diversity and variation in DNA methylation in Turkish accessions of Brachypodium that may be associated with climate variables and the molecular basis of which will feature in ongoing analyses.

A simplified method for characterising agronomic services provided by species-rich grasslands

2010 ◽  
Vol 61 (5) ◽  
pp. 420 ◽  
Author(s):  
Michel Duru ◽  
Pablo Cruz ◽  
Jean Pierre Theau
Keyword(s):  
Diversity Index ◽  
Field Measurements ◽  
Matter Content ◽  
Functional Ecology ◽  
Grass Species ◽  
Dry Matter Content ◽  
Functional Convergence ◽  
Trade Offs ◽  
Simplified Method ◽  
The Difference

In order to encourage farmers and their advisors to promote species-rich grasslands, the agronomic services they can provide should be demonstrated. Methods based on functional ecology are promising, but difficult to use in an applied context. Thus, we aimed to construct a simplified method, tailored for non-researchers, for assessing grassland agronomic services. We assess them by focusing on the grass species that was coupled to a leaf dry matter content (LDMC) database. These simplifications are supported by several hypotheses tested in our paper: (i) trade-offs between agronomic properties; (ii) mass ratio hypothesis; and (iii) functional convergence and divergence between grass and dicotyledonous species. The results were based on 37 vegetation records taken in the south of France (central Pyrenees, from 650 to 1250 m. a.s.l.) for calculating the proportion of grass species and the aggregated LDMC of grass species (LDMCgw), weighting species values by their abundance. LDMC of grass species was taken from field measurements and from a database. The two methods were compared. The latter avoids tedious field measurements, and we found that it was at least as good as the former for assessing agronomic productivity and quality, and the same was true for a LDMC diversity index. Reducing the list of grass species to the two dominant ones did not significantly alter the LDMCgw. There were significant differences between the grass and dicotyledonous components coexisting within a plant community for the digestibility of the plant components (higher for dicots) and in the date at which ceiling yield occurred (earlier for dicots), but no significant effect for productivity. For assessing agronomic services, we proposed corrections based on the grass : dicotyledon ratio. The hypotheses used for designing the method were verified. Finally, agronomic services such as herbage productivity and quality provided by species-rich grasslands can be evaluated by recording dominant grass species and the proportion of grass in the herbage. However, taking account of the difference in sensitivity to the environment for agronomic properties and plant species composition, the main use of the method is for ranking plant communities within a given area and a given year, rather than for providing absolute values of these agronomic properties.

Seedling growth and leaf surface morphological responses of three rangeland weeds to ultraviolet-B radiation

Weed Science ◽  
1999 ◽  
Vol 47 (4) ◽  
pp. 427-434 ◽  
Author(s):  
Nancy H. Furness ◽  
Mahesh K. Upadhyaya ◽  
Douglas P. Ormrod
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Leaf Surface ◽  
Epicuticular Wax ◽  
Matter Content ◽  
Ultraviolet B ◽  
Dry Matter Content ◽  
Fresh Weight ◽  
Shoot Ratio ◽  
Leaf Greenness

The influence of ultraviolet-B (UV-B) radiation on seedling growth and leaf surface characteristics of important rangeland weeds Cynoglossum officinale L. (houndstongue), Centaurea diffusa Lam. (diffuse knapweed), and Tragopogon pratensis L. (meadow salsify) was investigated in a greenhouse by exposing seedlings to 0, 7, or 11 kJ m−2 d−1 of biologically effective UV-B radiation. UV-B radiation reduced leaf, stem, and root fresh weights, leaf area, and leaf: shoot ratio and increased shoot dry matter content, specific leaf weight, and leaf greenness of C. officinale seedlings. Leaf, stem, and root fresh weight, and leaf area of C. diffusa seedlings decreased, whereas shoot dry matter content, specific leaf weight, leaf: shoot ratio, and leaf greenness were unaffected. T. pratensis seedlings exposed to UV-B radiation had diminished leaf greenness, but no change was observed in leaf or stem fresh weight, leaf area, or leaf: shoot ratio. Uniseriate trichome abundance in C. officinale seedlings increased and trichome orientation changed in response to UV-B exposure. UV-B treatments decreased uniseriate trichome abundance in C. diffusa; glandular trichome abundance and the ratio of glandular: uniseriate trichomes were not affected. T. pratensis seedlings showed no change in the amount of epicuticular wax on the adaxial leaf surface in response to UV-B irradiation. Shoot dry weight was not influenced by removal of epicuticular wax prior to UV-B exposure. Results suggest that epicuticular wax is not an important factor in acclimation of T. pratensis seedlings to UV-B radiation. Susceptibility to UV-B–induced damage was greatest for C. officinale seedlings and least for T. pratensis seedlings. Modification of plant morphology or reduction in growth induced by enhanced UV-B radiation may influence competitive relationships between rangeland weeds and their associated forage species.

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