scholarly journals Overgrazing-induced legacy effects may permit Leymus chinensis to cope with herbivory

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10116
Author(s):  
Fenghui Guo ◽  
Xiliang Li ◽  
Saheed Olaide Jimoh ◽  
Yong Ding ◽  
Yong Zhang ◽  
...  
Keyword(s):  
Induced Defense ◽  
Leymus Chinensis ◽  
Leaf Angle ◽  
Legacy Effects ◽  
Defense Strategies ◽  
Tolerance Strategy ◽  
Herbivory Tolerance ◽  
Below Ground ◽  
Simulated Grazing ◽  
Colonizing Ability

There is growing evidence that herbivory-induced legacy effects permit plants to cope with herbivory. However, herbivory-induced defense strategies in plants against grazing mammals have received little attention. To further understand the grazing-induced legacy effects on plants, we conducted a greenhouse experiment with Leymus chinensis experiencing different grazing histories. We focused on grazing-induced legacy effects on above-ground spatial avoidance and below-ground biomass allocation. Our results showed that L. chinensis collected from the continuous overgrazing plot (OG) exhibited higher performance under simulated grazing in terms of growth, cloning and colonizing ability than those collected from the 35-year no-grazing plot (NG). The enhanced adaptability of OG was attributed to increased above-ground spatial avoidance, which was mediated by larger leaf angle and shorter height (reduced vertical height and increased leaf angle contributed to the above-ground spatial avoidance at a lower herbivory stubble height, while reduced tiller natural height contributed to above-ground spatial avoidance at a higher herbivory stubble height). Contrary to our prediction, OG pre-allocated less biomass to the rhizome, which does not benefit the herbivory tolerance and avoidance of L. chinensis; however, this also may reflect a tolerance strategy where reduced allocation to rhizomes is associated with increased production of ramets.

Pathogen-induced Defense Strategies in Plants

2020 ◽  
Vol 23 (2) ◽  
pp. 97-105 ◽  
Author(s):  
Qari Muhammad Imran ◽  
Byung-Wook Yun
Keyword(s):  
Induced Defense ◽  
Defense Strategies

scholarly journals The Intensity of Simulated Grazing Modifies Costs and Benefits of Physiological Integration in a Rhizomatous Clonal Plant

2020 ◽  
Vol 17 (8) ◽  
pp. 2724
Author(s):  
Jushan Liu ◽  
Chen Chen ◽  
Yao Pan ◽  
Yang Zhang ◽  
Ying Gao
Keyword(s):  
Compensatory Growth ◽  
Grazing Intensity ◽  
Clonal Plants ◽  
Physiological Integration ◽  
Leymus Chinensis ◽  
Moderate Intensity ◽  
Heterogeneous Environments ◽  
Simulated Grazing ◽  
Net Benefits ◽  
Benefits And Costs

Clonal plants in grasslands are special species with physiological integration which can enhance their ability to tolerate herbivory stress especially in heterogeneous environments. However, little is known about how grazing intensity affects the trade-off between the benefits and costs of physiological integration, and the mechanism by which physiological integration improves compensatory growth in response to herbivory stress. We examined the effects of simulated grazing intensity on compensatory growth and physiological integration in a clonal species Leymus chinensis with a greenhouse experiment. This experiment was conducted in a factorial design involving nutrient heterogeneity (high-high, high-low, low-high, low-low), simulated grazing by clipping (0%, 25%, 50% or 75% shoot removal) and rhizome connection (intact versus severed) treatments. Compensatory indexes at 25% and 50% clipping levels were higher than that at 75% clipping level except in low-low nutrient treatments. Physiological integration decreased and increased compensatory indexes when the target-ramets worked as exporter and importer, respectively. Generally, clipping increased both benefits and costs of physiological integration, but its net benefits (benefits minus costs) changed with clipping intensity. Physiological integration optimized compensatory growth at light and moderate clipping intensity, and its net benefits determined the high capacity of compensatory growth. Grassland managements such as grazing or mowing at light and moderate intensity would maximize the profit of physiological integration and improve grassland sustainability.

scholarly journals Clonal versus non-clonal milkweeds (Asclepias spp.) respond differently to stem damage, affecting oviposition by monarch butterflies

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10296
Author(s):  
Elise He ◽  
Anurag A. Agrawal
Keyword(s):  
Life History ◽  
Induced Defense ◽  
Egg Laying ◽  
Larval Performance ◽  
Monarch Butterflies ◽  
Leaf Quality ◽  
Defense Strategies ◽  
Plant Damage ◽  
And Control ◽  
Clonal Species

Background Oviposition decisions are critical to the fitness of herbivorous insects and are often impacted by the availability and condition of host plants. Monarch butterflies (Danaus plexippus) rely on milkweeds (Asclepias spp.) for egg-laying and as food for larvae. Previous work has shown that monarchs prefer to oviposit on recently regrown plant tissues (after removal of above-ground biomass) while larvae grow poorly on plants previously damaged by insects. We hypothesized that these effects may depend on the life-history strategy of plants, as clonal and non-clonal milkweed species differ in resource allocation and defense strategies. Methodology/Principal Findings We first confirmed butterfly preference for regrown tissue in a field survey of paired mowed and unmowed plots of the common milkweed A. syriaca. We then experimentally studied the effects of plant damage (comparing undamaged controls to plants clipped and regrown, or damaged by insects) on oviposition choice, larval performance, and leaf quality of two closely related clonal and non-clonal species pairs: (1) A. syriaca and A. tuberosa, and (2) A. verticillata and A. incarnata. Clonal and non-clonal species displayed different responses to plant damage, impacting the proportions of eggs laid on plants. Clonal species had similar mean proportions of eggs on regrown and control plants (≈35–40% each), but fewer on insect-damaged plants (≈20%). Meanwhile non-clonal species had similar oviposition on insect-damaged and control plants (20–30% each) but more eggs on regrown plants (40–60%). Trait analyses showed reduced defenses in regrown plants and we found some evidence, although variable, for negative effects of insect damage on subsequent larval performance. Conclusions/Significance Overall, non-clonal species are more susceptible and preferred by monarch butterflies following clipping, while clonal species show tolerance to clipping and induced defense to insect herbivory. These results have implications for monarch conservation strategies that involve milkweed habitat management by mowing. More generally, plant life-history may mediate growth and defense strategies, explaining species-level variation in responses to different types of damage.

Do compensatory shoot growth and mycorrhizal symbionts act as competing above- and below-ground sinks after simulated grazing?

Plant Ecology ◽  
2010 ◽  
Vol 212 (1) ◽  
pp. 33-42 ◽  
Author(s):  
Sari Piippo ◽  
Annamari Markkola ◽  
Esa Härmä ◽  
Juha Tuomi
Keyword(s):  
Shoot Growth ◽  
Below Ground ◽  
Simulated Grazing

scholarly journals Historic Grazing Enhances Root-Foraging Plasticity and Assimilation But Not Absorbability For Nitrogen of Clonal Offspring in Leymus Chinensis

2021 ◽  
Author(s):  
Xiliang Li ◽  
Ningning Hu ◽  
Jingjing Yin ◽  
Weibo Ren ◽  
Ellen Fry
Keyword(s):  
N Uptake ◽  
Utilization Efficiency ◽  
Leymus Chinensis ◽  
Legacy Effects ◽  
Asexual Propagation ◽  
Legacy Effect ◽  
Grassland Plants ◽  
N Assimilation ◽  
Assimilation Capacity

Abstract Aims Plants with a history of overgrazing show trait-mediated legacy effects. These legacy effects strongly influence growth dynamics and stress tolerance of grassland plants, thus impacting ecosystem functioning. Long-term overgrazing has strong effects on plant growth and carbon assimilation via asexual propagation. However, the links between nitrogen (N) cycling and grazing-induced plant legacy effects are largely unknown.Methods We tested the strength of legacy effects of long-term overgrazing on N metabolism in the clonal plant Leymus chinensis, and its associated changes at the physiological and molecular levels. These tests were conducted in both field and greenhouse experiments.Results The clonal offspring of overgrazed L. chinensis were significantly smaller than the control offspring, with lower individual N uptake and N utilization efficiency, indicating that the N dynamics were impacted by plant legacy effects. The response ratios of root traits to N patches in the clonal offspring of overgrazed L. chinensis were significantly higher than those of the control, indicating that root nutrient foraging plasticity increased to cope with grazing-induced N heterogeneity. Moreover, the observed plant legacy effects slightly decreased N absorbability in roots but significantly increased N assimilation capacity, by increasing N resorption efficiency in particular, with biotic stress memory activated at the enzymatic and transcriptional levels.Conclusions We propose that multigenerational exposure of perennial plants to herbivore foraging can produce a legacy effect on nutrient uptake, which offers insights into the potential resilience of grasslands to overgrazing.

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