Plant Allocation Research Articles

Soil legacy effects on biomass allocation depend on native plant diversity in the invaded community.

The biodiversity of aboveground plants and belowground microbes is key for plant communities resisting exotic plant invasion. Whether the soil legacy effects after the invasion are related to the diversity of the invaded community is less studied. Soils from invaded communities were collected and potted to investigate the effects of the invasive community's legacy on the biomass allocation of plants that later grew in these soils. The plots where native plants were present had relatively high nutrient levels (except for available nitrogen) compared to the monodominance communities invaded by Chromolaena odorata. This also indirectly suggests that the severe invasion of C. odorata depleted the nutrients in the soil to a greater extent. When soils were from communities with only C. odorata or one native plant, their biotic legacies showed a significantly positive effect on biomass accumulation of subsequent invasive plants, but this positive effect became negative when more than two native plants were present in the invaded community. This result indicated that the effect of biological resistance increases with the number increase of native species in the invaded communities. The soil legacy effect of the invaded communities on subsequent plants depended on the diversity of native plants. This study can provide insights into the mechanisms of soil biological resistance to exotic plant invasion and provide a theoretical basis for the removal of soil legacy effects after the exotic plant invasion.

Study on plant allocation method of landscape architecture based on comprehensive evaluation index method

Aiming at the problems of poor allocation accuracy and low environmental contribution rate in landscape plant allocation methods, a landscape plant allocation method based on comprehensive evaluation index method is proposed in this paper. First, he spatial state of abstract landscape plant configuration is regarded as the spatial sequence of specific configuration points and lines, and the characteristics of different levels of space are constructed. Then, calculate the index weight with the help of analytic hierarchy process to complete the construction of allocation index system. Finally, with the help of the comprehensive evaluation index method, the single category factor index and similar index are determined, the contribution rate of configured plants to the environmental impact is calculated, the landscape plant configuration model is constructed, and the landscape plant configuration is completed. The results show that the configuration accuracy of the proposed method is high.

A Two-Stage Optimization Model of Capacity Allocation and Regulation Operation for Virtual Power Plant

Capacity allocation and optimal scheduling of virtual power plants (VPP) are important aspects to ensure the effectiveness of system investment and operational economy. In this study, a two-stage optimization model for capacity planning and regulation operation of VPPs considering source-load-storage resources is constructed. In the first stage, a capacity optimization model is constructed for the VPP with the lowest annual economic cost under the refinement constraints of source-storage resources. In the second stage, based on the capacity allocation results and load characteristics, a source-load interactive operation optimization model with the lowest typical daily operating cost and incentive-based demand response is constructed under the resource capacity constraint, so as to realize the capacity allocation and energy control of the VPPs in all stages of source-load-storage resources. Finally, a planning solver is applied to solve the algorithm. The proposed model is validated. The results show that the presence or absence of demand response, the form of demand response, and the charge state of energy storage all have an impact on the allocation and operation results. Adequate consideration of the source-side, load-side, and storage-side interactions can provide a reference for more accurate planning and optimization. The research results are intended to be able to provide VPPs investors and operators with a full process of construction and operation solutions.

Regulating carbon and water balance as a strategy to cope with warming and drought climate in Cunninghamia lanceolata in southern China.

Human activities have increased the possibility of simultaneous warming and drought, which will lead to different carbon (C) allocation and water use strategies in plants. However, there is no conclusive information from previous studies. To explore C and water balance strategies of plants in response to warming and drought, we designed a 4-year experiment that included control (CT), warming (W, with a 5°C increase in temperature), drought (D, with a 50% decrease in precipitation), and warming and drought conditions (WD) to investigate the non-structural carbohydrate (NSC), C and nitrogen (N) stoichiometry, and intrinsic water use efficiency (iWUE) of leaves, roots, and litter of Cunninghamia lanceolata, a major tree species in southern China. We found that W significantly increased NSC and starch in the leaves, and increased NSC and soluble sugar is one of the components of NSC in the roots. D significantly increased leaves' NSC and starch, and increased litter soluble sugar. The NSC of the WD did not change significantly, but the soluble sugar was significantly reduced. The iWUE of leaves increased under D, and surprisingly, W and D significantly increased the iWUE of litter. The iWUE was positively correlated with NSC and soluble sugar. In addition, D significantly increased N at the roots and litter, resulting in a significant decrease in the C/N ratio. The principal component analysis showed that NSC, iWUE, N, and C/N ratio can be used as identifying indicators for C. lanceolata in both warming and drought periods. This study stated that under warming or drought, C. lanceolata would decline in growth to maintain high NSC levels and reduce water loss. Leaves would store starch to improve the resiliency of the aboveground parts, and the roots would increase soluble sugar and N accumulation to conserve water and to help C sequestration in the underground part. At the same time, defoliation was potentially beneficial for maintaining C and water balance. However, when combined with warming and drought, C. lanceolata growth will be limited by C, resulting in decreased NSC. This study provides a new insight into the coping strategies of plants in adapting to warming and drought environments.

Dynamics of Crop Evapotranspiration of Four Major Crops on a Large Commercial Farm: Case of the Navajo Agricultural Products Industry, New Mexico, USA

Crop evapotranspiration (ETa) is the main source of water loss in farms and watersheds, and with its effects felt at a regional scale, it calls for irrigation professionals and water resource managers to accurately assess water requirements to meet crop water use. On a multi-crop commercial farm, different factors affect cropland allocation, among which crop evapotranspiration is one of the most important factors regarding the seasonally or annually available water resources for irrigation in combination with the in-season effective precipitation. The objective of the present study was to estimate crop evapotranspiration for four major crops grown on the Navajo Agricultural Products Industry (NAPI) farm for the 2016–2010 period to help crop management in crop plant allocation based on the different objectives of the NAPI. The monthly and seasonal satellite-based ETa of maize, potatoes, dry beans, and alfalfa were retrieved and compared using the analysis of variance and the least significant difference (LSD) at 5% of significance. Our results showed the highly significant effects of year, months, and crops. The year 2020 obtained the highest crop ETa, and July had the most evapotranspiration demand, followed by August, June, September, and May, and the pool of April, March, February, January, December, and November registered the lowest crop ETa. Maize monthly ETa varied from 17.5 to 201.7 mm with an average seasonal ETa of 703.8 mm. The monthly ETa of potatoes varied from 9.8 to 207.5 mm, and their seasonal ETa averaged 600.9 mm. The dry bean monthly ETa varied from 10.4 to 178.4 mm, and the seasonal ETa averaged 506.2 mm. The alfalfa annual ETa was the highest at 1015.4 mm, as it is a perennial crop. The alfalfa monthly ETa varied from 8.2 to 202.1 mm. The highest monthly crop ETa was obtained in July for all four crops. The results of this study are very critical for cropland allocation and irrigation management under limited available water across a large commercial farm with multiple crops and objectives.

Responses of plant C:N:P stoichiometry to soil properties on unstable slopes of dry-hot valley

In this study, we examined plant C:N:P stoichiometry of herbaceous plants in different sections (stable area, unstable area and deposition area) of the unstable slope on both shade and sunny aspects of dry-hot valley with different soil properties. The results showed that C concentration (320.59 g·kg-1), N concentration (12.15 g·kg-1), and N:P ratio (25.37) of shoot on the unstable slope were significantly higher than those of root, with 254.01 g·kg-1, 6.12 g·kg-1 and 13.43, respectively. The average value of the C:N ratio was significantly higher in root (43.09) than shoot (31.90). The C content and N:P ratio of shoot and root in stable and unstable areas were significantly higher than in deposition area, whereas the N content in unstable area was significantly higher than that in deposition area on the sunny slope. In addition, the N and P contents of shoot and the root P content in deposition area were significantly higher than in stable and unstable areas, whereas the C content of root in stable and unstable areas were significantly higher than in deposition area on the shade slope. Moreover, the shoot growth of plants was mainly limited by P, whereas root growth was mainly limited by N and the limitation gradually increased as the section goes down. Soil water content (SWC) was an important factor controlling the C, N, and P contents change of shoot with the relative influence ratios of 28.8%, 20.8%, and 19.9%, respectively. Soil organic carbon (SOC) had a significant impact on the C and P contents of root with the relative influence ratios of 49.5% and 22.1%. The change of root N content was mainly affected by soil pH (24.3%). Our results revealed that nutrient allocation of plant was significantly affected by slope aspects, sections and soil factors, which were mainly constituted by SWC, SOC, and soil pH.

Mycorrhizal Types Regulated the Responses of Biomass in Different Plant Organs to N Addition

Nitrogen (N) deposition is known to significantly affect plant growth. Mycorrhizas play an important role in plant productivity, and plants of different mycorrhizal types respond differently to global change, which will inevitably affect plant response to N deposition. However, little is known about the differences of different mycorrhizas in biomass allocation of host plants in response to N addition. Here, a meta-analysis of data from N addition experiments was carried out to analyze the response of biomass in arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM) plants to N addition. The results showed that biomass of leaf, stem, fine root (FR), and litter between AM and ECM plants responded differently to N addition (p < 0.05). Among them, biomass of leaf and stem in ECM plants (leaf: 46.89%; stem: 45.59%) was more sensitive (positively) to N addition than AM plants (leaf: 27.84%; stem: 10.30%) (p < 0.05). N addition suppressed biomass of FR in AM plants (−11.22%) but promoted that in ECM plants (13.77%). The effects on biomass also varied with different functional groups between AM and ECM plants. However, the N responses were influenced by other resources. When other treatments were added, biomass was less varied in AM plants compared to ECM plants. In addition, the N response of WB (whole biomass) and root biomass were positively correlated with annual temperature in ECM plants, but that in AM plants did not. The effects on shoot biomass in AM and ECM plants to N addition both decreased with annual temperature. The N response of root biomass increased with annual precipitation. It can be seen that different mycorrhizal types regulate the response of different plant organ biomass to N addition, which is significant for predicting ecosystem responses and feedback to environmental change.

Quantifying tropical forest disturbances using canopy structural traits derived from terrestrial laser scanning

Forest disturbances can reduce the potential of ecosystems to provide resources and services. Despite the urgent need to understand the effects of logging on tropical ecosystems, the quantification of disturbances arising from selective logging remains a challenge. Here, we used canopy-three-dimensional information retrieved from Terrestrial Laser Scanner (TLS) measurements to investigate the impacts of logging on key structural traits relevant to forest functioning. We addressed the following questions: 1) Which canopy structural traits were mostly affected by logging? 2) Can remotely-sensed canopy structural traits be used to quantify forest disturbances? Fourteen canopy structural traits were applied as input to machine learning models, which were trained to quantify the intensity of logging disturbance. The plots were located in Malaysian Borneo, over a gradient of logging intensity, ranging from forest not recently disturbed by logging, to forest at the early stage of recovery following logging. Our results showed that using the Random Forest regression approach, the Plant Area Index (PAI) between 0 m − 5 m aboveground, Relative Height at 50 %, and metrics describing plant allocation in the middle-higher canopy layer were the strongest predictors of disturbance. In particular, PAI between 35 m and 40 m explained 12 % to 19 % of the structural variability between plots, followed by the relative height at 50 %, (10.5 % − 18.6 %), and the foliage height diversity (7.5 % − 16.9 %). The approach presented in this study allowed a spatially explicitly characterization of disturbances, providing a novel approach for quantifying and monitoring the integrity of tropical forests. Our results indicate that canopy structural traits can provide a robust indication of disturbances, with strong potential to be applied at regional or global scales. The data used in this study are openly available and we encourage other researchers to use them as a benchmark data set to test larger scale approaches based on satellite and airborne platforms.

Elevated CO2 alleviates adverse effects of drought on plant water relations and photosynthesis: A global meta‐analysis

Abstract The elevated CO2 concentration (eCO2) is expected to improve plant water relations and carbon (C) uptakes, with a potential to mitigate drought stress. However, the interactive effects of eCO2 and drought on plant physiology and growth are not clear. We performed a meta‐analysis on the interactive effects of eCO2 and drought on plant water relations, photosynthesis, biomass production and allocation. We found that eCO2 did not lead to the conservation of soil water, but improved leaf water status under drought conditions as evidenced by a higher leaf relative water content (LRWC) and a less negative midday leaf water potential, resulting from reduced stomatal conductance (gs) and increased root to shoot ratio. Elevated CO2 retarded the response of gs to drought, which may be mediated by the decrease in leaf abscisic acid concentration under eCO2 and drought. Drought imposed stomatal limitations on photosynthesis (A), which was alleviated by eCO2 via increasing intercellular CO2 concentration (Ci). This led to a stronger A response to eCO2 under drought, supporting the ‘low Ci effect’. However, no interaction of eCO2 and drought was detected on plant biomass production. Intrinsic water use efficiency (iWUE) increased proportionally with eCO2, while plant‐scale WUE was less responsive to eCO2. C3 plants had advantages over C4 plants in terms of A and biomass production under eCO2 and well‐watered conditions rather than under eCO2 and drought conditions. Drought caused a greater reduction in biomass for woody plants than for herbs. Plants growing in pots showed greater decreases in the physiology and biomass under drought than those growing in field. Synthesis. These findings suggest that eCO2 can alleviate the adverse impacts of drought on plant water relations and C sequestration, and are of significance in the prediction of plant growth and ecosystem productivity under global changes.

Disentangling the effects of jasmonate and tissue loss on the sex allocation of an annual plant.

Selection through pollinators plays a major role in the evolution of reproductive traits. However, herbivory can also induce changes in plant sexual expression and sexual systems, potentially influencing conditions governing transitions between sexual systems. Previous work has shown that herbivory has a strong effect on sex allocation in the wind-pollinated annual plant Mercurialis annua, likely via responses to resource loss. It is also known that many plants respond to herbivory by inducing signaling, and endogenous responses to it, via the plant hormone jasmonate. Here, we attempt to uncouple the effects of herbivory on sex allocation in M. annua through resource limitation (tissue loss) versus plant responses to jasmonate hormone signaling. We used a two-factorial experiment with four treatment combinations: control, herbivory (25% chronic tissue loss), jasmonate, and combined herbivory and jasmonate. We estimated the effects of tissue loss and defense-inducing hormones on reproductive allocation, male reproductive effort, and sex allocation. Tissue loss caused plants to reduce their male reproductive effort, resulting in changes in total sex allocation. However, application of jasmonate after herbivory reversed its effect on male investment. Our results show that herbivory has consequences on plant sex expression and sex allocation, and that defense-related hormones such as jasmonate can buffer the impacts. We discuss the physiological mechanisms that might underpin the effects of herbivory on sex allocation, and their potential implications for the evolution of plant sexual systems.

Discussion on the Difficulties and Strategies Faced by the Development of Garden Greening in Hohhot, China

At present, people living in cities have high requirements for urban environment and greening level. Many cities are also constantly improving their greening level, actively building a good urban appearance, and providing higher quality environmental conditions for the general public. Through active efforts, many cities have achieved good results in landscaping, and the level of urban greening has been significantly improved. However, in the specific process of landscape development, many cities have also encountered certain difficulties and problems, which need to be solved urgently. Taking Hohhot city of China as an example, based on the analysis of its basic situation, the paper comprehensively analyzes the difficulties it faces in the development of landscaping, and then puts forward corresponding countermeasures from the aspects of rational plant allocation and active development of three-dimensional greening, aiming at the unreasonable situation in the selection and configuration of garden plants, as well as the imperfect management and inadequate three-dimensional greening.

Phenological and physiological advantages of invasive annuals are strengthened by nitrogen enrichment

Abstract Anthropogenic nitrogen (N) deposition exerts profound influence on the composition and function of native ecosystems, commonly resulting in reduced plant richness and increases in nonnative plant invasion. Identifying differences in plant N responses and functional traits could help to explain the ongoing invasion and biological impoverishment of ecosystems subject to N deposition. We compared the growth, emergence phenology and functional traits of 30 native and invasive annual plant species under high and low N availability, with the goal of evaluating if invasives exhibit functionally dissimilar responses to N compared with the native species they displace. Invasives grew larger than natives, especially under increased N availability. Overall, invasives and natives did not differ in emergence phenology. However, these groups of species differed in relationships between growth and days to emergence, and N addition further strengthened these differences; invasives consistently grew larger than natives that emerged around the same time, whereas natives showed a strong negative effect of delayed emergence on plant growth. Relative N responses for measures of plant growth and allocation did not differ between native and invasive species, but invasives exhibited greater plasticity in physiological traits. This included significantly lower leaf N content, higher CN ratios and greater water‐use efficiency (WUE) in plants grown under high N. Invasives also showed functionally different patterns of growth and water use. Across species, invasives showed a positive relationship between shoot growth and WUE. Native species showed a trade‐off between root allocation and WUE, whereas invasives displayed high values for WUE even despite reduced root: shoot ratios under high N. Our results highlight the ability of invasives to rapidly accrue biomass, disproportionately benefit from early emergence and N addition and use water efficiently despite rapid growth. Natives, on the other hand, pay a higher cost for delayed emergence and may experience trade‐offs between growth and water use. The more pronounced functional differences between natives and invasives observed under high N likely play an important role in driving invasion and reduced species diversity under N enrichment. These differences could be used to inform successful management strategies for N‐impacted and water‐limited ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Global systematic review with meta-analysis shows that warming effects on terrestrial plant biomass allocation are influenced by precipitation and mycorrhizal association

Biomass allocation in plants is fundamental for understanding and predicting terrestrial carbon storage. Yet, our knowledge regarding warming effects on root: shoot ratio (R/S) remains limited. Here, we present a meta-analysis encompassing more than 300 studies and including angiosperms and gymnosperms as well as different biomes (cropland, desert, forest, grassland, tundra, and wetland). The meta-analysis shows that average warming of 2.50 °C (median = 2 °C) significantly increases biomass allocation to roots with a mean increase of 8.1% in R/S. Two factors associate significantly with this response to warming: mean annual precipitation and the type of mycorrhizal fungi associated with plants. Warming-induced allocation to roots is greater in drier habitats when compared to shoots (+15.1% in R/S), while lower in wetter habitats (+4.9% in R/S). This R/S pattern is more frequent in plants associated with arbuscular mycorrhizal fungi, compared to ectomycorrhizal fungi. These results show that precipitation variability and mycorrhizal association can affect terrestrial carbon dynamics by influencing biomass allocation strategies in a warmer world, suggesting that climate change could influence belowground C sequestration.

Precipitation-mediated responses of plant biomass production and allocation to changing soil pH in semiarid grasslands

Biomass and its allocation are crucial to understand carbon cycling. Climate change and human disturbance potentially alter soil pH, but it remains unclear how biomass production and its partitioning respond to altered soil pH. Here, we investigated how changing soil pH (acidification and alkalization) affected above- and belowground biomass production and allocation (hereafter AB, BB and BB/AB, respectively) at nine sites representing desert, typical, and meadow grasslands with increasing precipitation across a 1500-km transect in Inner Mongolia, China. The results showed that soil acidification reduced AB in typical and meadow grasslands, whereas soil alkalization reduced AB in desert and typical grasslands. Changing soil pH did not affect BB in desert or typical grasslands, but reduced BB in meadow grasslands. Altered soil pH negatively impacted species richness, Shannon-Wiener diversity, and dominant species biomass across all grasslands. BB/AB was increased by soil acidification and alkalization along the study transect. Soil C, N and C:N ratio were not affected by changing soil pH in three types of grasslands. Response ratios of AB, BB/AB and dominant species biomass were positively correlated with precipitation under altered soil pH, whereas response ratios of BB were negatively correlated with precipitation under soil alkalization. Variance partitioning analysis showed that the response of biomass and its allocation to altered soil pH were mainly explained by community composition but not soil fertility. Structural equation model analysis demonstrated that precipitation mediated the responses of biomass distribution to soil pH changes in semi-arid grasslands mainly via altering the response of dominant species. Our results indicate that dry grasslands with low productivity and precipitation generally allocate more C to belowground than wet grasslands regardless of pH change. These findings can improve our predictions of carbon dynamics in grassland ecosystems under climate change.

Process-oriented analysis of dominant sources of uncertainty in the land carbon sink

The observed global net land carbon sink is captured by current land models. All models agree that atmospheric CO2 and nitrogen deposition driven gains in carbon stocks are partially offset by climate and land-use and land-cover change (LULCC) losses. However, there is a lack of consensus in the partitioning of the sink between vegetation and soil, where models do not even agree on the direction of change in carbon stocks over the past 60 years. This uncertainty is driven by plant productivity, allocation, and turnover response to atmospheric CO2 (and to a smaller extent to LULCC), and the response of soil to LULCC (and to a lesser extent climate). Overall, differences in turnover explain ~70% of model spread in both vegetation and soil carbon changes. Further analysis of internal plant and soil (individual pools) cycling is needed to reduce uncertainty in the controlling processes behind the global land carbon sink.

The Iron Deficiency-Regulated Small Protein Effector FEP3/IRON MAN1 Modulates Interaction of BRUTUS-LIKE1 With bHLH Subgroup IVc and POPEYE Transcription Factors.

In light of climate change and human population growth one of the most challenging tasks is to generate plants that are Fe-efficient, resilient to low Fe supply and Fe-biofortified. For such endeavors, it is crucial to understand the regulation of Fe acquisition and allocation in plants. One open question is how identified Fe-regulatory proteins comprising positive and negative regulators act together to steer Fe homeostasis. bHLH transcription factors (TFs) belonging to the subgroups IVb and IVc can initiate a bHLH cascade controlling the –Fe response in roots. In Arabidopsis thaliana, the –Fe-induced genes are sub-divided into several gene co-expression clusters controlled by different sets of TFs. Some of the co-expressed genes encode regulatory E3 ligase proteins BRUTUS (BTS)/BTS-LIKE (BTSL) and small proteins belonging to the group of FE UPTAKE-INDUCING PEPTIDE/IRON MAN (FEP/IMA). Recently, it was described that FEP1/IMA3 and FEP3/IMA1 proteins inhibit the repression of bHLH factors by BTS. We had postulated that –Fe-regulated co-expression clusters provide new information about regulatory protein interaction complexes. Here, we report a targeted yeast two-hybrid screen among 23 proteins of the –Fe response. This identified a novel protein interactome involving another E3 ligase, namely BTSL1, basic helix-loop-helix (bHLH) protein POPEYE (PYE) and transcription factors of the subgroup IVc as well as FEP3/IMA1. Because of the difficulty in stable BTSL1 protein expression in plant cells, we used a yeast two hybrid-based deletion mapping, homology modeling and molecular docking, to pinpoint interaction sites in BTSL1 and FEP3/IMA1. bHLH IVc TFs have similar residues at their C-terminus as FEP3/IMA1 interacting sites. FEP3/IMA1 attenuated interaction of BTSL1 and bHLH proteins in a yeast three-hybrid assay, in line with physiological data pointing to enhanced Fe acquisition and allocation in FEP3/IMA1 overexpression and btsl1 btsl2 mutant plants. Hence, exploiting –Fe-induced gene co-expression networks identified FEP3/IMA1 as a small effector protein that binds and inhibits the BTSL1 complex with PYE and bHLH subgroup IVc proteins. Structural analysis resolved interaction sites. This information helps improving models of Fe regulation and identifying novel targets for breeding of Fe-efficient crops.

Arbuscular mycorrhizal colonization increases plant above-belowground feedback in a northwest Chinese coal mining-degraded soil by increasing photosynthetic carbon assimilation and allocation to maize.

A three-compartment culture system was used to study the mechanism by which the AM fungus Funneliformis mosseae influences host plant growth and soil organic carbon (SOC) content in a northwest China coal mining area. A 13CO2 pulse tracing technique was used to trace the allocation of maize photosynthetic C in shoots, roots, AM fungus, and soil. Carbon accumulation and allocation in mycorrhizal (inoculated with Funneliformis mosseae) and non-mycorrhizal treatments were detected. AM fungal inoculation significantly increased the 13C concentration and content in both above- and below-ground plant parts and also significantly enhanced anti-aging ability by increasing soluble sugars and catalase activity (CAT) in maize leaves while reducing foliar malondialdehyde content (MDA) and leaf temperature and promoted plant growth. AM fungi also increased P uptake to promote maize growth. Soil organic carbon (SOC), glomalin, microbial biomass carbon (MBC), and nitrogen (MBN) contents increased significantly after inoculation. A mutually beneficial system was established involving maize, the AM fungus and the microbiome, and the AM fungus became an important regulator of C flux between the above- and below-ground parts of the system. Inoculation with the AM fungus promoted plant growth, C fixation and allocation belowground to enhance soil quality. A positive above-belowground feedback appeared to be established.

Kin recognition benefits clonal offspring performance of historically grazed Leymus chinensis: insights for grassland management

BackgroundIndividual plants can identify their neighbors and adjust their biomass investment to avoid competing with their relatives or jointly cope with external stresses. Maternal effects can improve their offspring adaptability under external stresses. However, how grazing-induced maternal effects influence plant kin interactions remain unknown.MethodsClonal offspring of Leymus chinensis grown under multi-year grazing and non-grazing conditions were used for this study. A greenhouse experiment was conducted to evaluate the performance of focal plants in the presence of kin and stranger neighbors, with the aim of analyzing the interaction between maternal effect and kin relatedness.ResultsKin relatedness of neighboring plants affected the biomass production and allocation of focal plants, demonstrating the presence of kin recognition in L. chinensis. Moreover, grazing-induced maternal effects significantly enhanced kin recognition in the species. Consequently, the presence of stranger neighbors significantly improved the growth potential of grazed offspring. Specifically, the total biomass of clonal offspring increased by 73.1% compared to the kin group, potentially buffering grazing-induced plant productivity declines.ConclusionsThis study shows that historical grazing enhances kin recognition in L. chinensis. Thus, introducing multi-genotypic plants can increase the productivity of grasslands. The findings of this study enhance our understanding of intraspecific plant–plant interactions in clonal species and provide new insights into sustainable grassland management.

Herbivore population dynamics in response to plant allocation strategies

When herbivores feed, plants may respond by altering the quantity of edible biomass available to future feeders through mechanisms such as compensatory regrowth of edible structures or allocation of biomass to inedible reserves. Previous work showed that some forms of compensatory regrowth can drive insect outbreaks, but this work assumed regrowth occurred without any energetic cost to the plant. While this is a useful simplifying assumption for gaining preliminary insights, plants face an inherent trade-off between allocating energy to regrowth versus storage. Therefore, we cannot truly understand the role of compensatory regrowth in driving insect outbreaks without continuing on to more realistic scenarios. In this paper, we model the interaction between insect herbivores and plants that have a trade-off between compensatory regrowth and allocation to inedible reserves in response to herbivory. We found that the plant’s allocation strategy, described in our model by parameters representing the strength of the overcompensatory response and the rates at which energy is stored and mobilized for growth, strongly affects whether herbivore outbreaks occur. Additional factors, such as the strength of food limitation and herbivore interference while feeding, influence the frequency of the outbreaks. Overall, we found a possible new role of overcompensation to promote herbivore fluctuations when it co-occurs with allocation to inedible reserves. We highlight the importance of considering trade-offs between tolerance mechanisms that plants use in response to herbivory by showing that new dynamics arise when different plant allocation strategies occur simultaneously.

Biomass partitioning of plants under soil pollution stress

Polluted sites are ubiquitous worldwide but how plant partition their biomass between different organs in this context is unclear. Here, we identified three possible drivers of biomass partitioning in our controlled study along pollution gradients: plant size reduction (pollution effect) combined with allometric scaling between organs; early deficit in root surfaces (pollution effect) inducing a decreased water uptake; increased biomass allocation to roots to compensate for lower soil resource acquisition consistent with the optimal partitioning theory (plant response). A complementary meta-analysis showed variation in biomass partitioning across published studies, with grass and woody species having distinct modifications of their root: shoot ratio. However, the modelling of biomass partitioning drivers showed that single harvest experiments performed in previous studies prevent identifying the main drivers at stake. The proposed distinction between pollution effects and plant response will help to improve our knowledge of plant allocation strategies in the context of pollution.