Variation In Root Traits Research Articles

Long-term nitrogen addition modifies fine root growth and vertical distribution by affecting soil nutrient availability in a Mongolian pine plantation

Fine roots are the primary organ of tree species in water and nutrient acquisition, and are the major contributor of forest soil organic carbon (C). However, it remains largely unknown how fine root growth dynamics and vertical distribution respond to long-term nitrogen (N) enrichment, which prevents us from accurately evaluating forest C sequestration potential under N deposition. Here, we investigated the effects of nine-year N addition (0 and 10 g N m−2 year−1) on fine root nutrients, biomass, production, turnover rate and vertical distribution in three soil layers (0–10, 10–20 and 20–40 cm) of a Mongolian pine (Pinus sylvestris var. mongolica) plantation in the Keerqin Sandy Lands, Northeast China. We found that soil inorganic N was increased and Olsen-P was decreased by N addition. N addition increased fine root N, C:P and N:P ratios, but reduced fine root P and C:N ratio across all soil layers. N addition reduced fine root biomass in 0–10 cm soil layer but increased it in 20–40 cm soil layer. N addition accelerated fine root turnover rate in 0–10 cm soil layer, and increased fine root necromass across all soil layers. Moreover, N addition significantly enhanced biomass of ectomycorrhizal extraradical hyphae in the 0–10 cm soil layer. Redundancy analysis showed that variations of fine root traits were well explained by soil NO3−-N in 0–10 and 10–20 cm soil layers, and by soil NH4+-N and Olsen-P in 20–40 cm soil layer. Collectively, our results highlight the shift from N limitation to P limitation of Mongolian pine plantations under long-term N addition, and suggest that changes in fine root growth and vertical distribution induced by N addition could accelerate belowground C allocation in Mongolian pine plantations.

Temporal phenotypic variation of spinach root traits and its relation to shoot performance

The root system is important for the growth and development of spinach. To reveal the temporal variability of the spinach root system, root traits of 40 spinach accessions were measured at three imaging times (20, 30, and 43 days after transplanting) in this study using a non-destructive and non-invasive root analysis system. Results showed that five root traits were reliably measured by this system (RootViz FS), and two of which were highly correlated with manually measured traits. Root traits had higher variations than shoot traits among spinach accessions, and the trait of mean growth rate of total root length had the largest coefficients of variation across the three imaging times. During the early stage, only tap root length was weakly correlated with shoot traits (plant height, leaf width, and object area (equivalent to plant surface area)), whereas in the third imaging, root fresh weight, total root length, and root area were strongly correlated with shoot biomass-related traits. Five root traits (total root length, tap root length, total root area, root tissue density, and maximal root width) showed high variations with coefficients of variation values (CV ≥ 0.3, except maximal root width) and high heritability (H2 > 0.6) among the three stages. The 40 spinach accessions were classified into five subgroups with different growth dynamics of the primary and lateral roots by cluster analysis. Our results demonstrated the potential of in-situ phenotyping to assess dynamic root growth in spinach and provide new perspectives for biomass breeding based on root system ideotypes.

Root traits vary as much as leaf traits and have consistent phenotypic plasticity among 14 populations of a globally widespread herb

Abstract Our understanding of plant functional trait variation among populations and how this relates to local adaptation to environmental conditions is largely shaped by above‐ground traits. However, we might expect below‐ground traits linked to resource acquisition and conservation to vary among populations that experience different environmental conditions. Alternatively, below‐ground traits might be highly plastic in response to growing conditions, such as availability of soil resources and association with symbiont arbuscular mycorrhizal fungi (AMF). We assessed (i) the strength of among‐population variation in above‐ and below‐ground traits, (ii) the effects of growing conditions on among‐population variation and (iii) whether variation among populations is linked to source environment conditions, in a globally distributed perennial Plantago lanceolata. Using seeds from 14 populations across three continents, we grew plants in a common garden experiment and measured leaf and root traits linked to resource acquisition and water conservation. We included two sets of experimental treatments (high or low water availability; with and without AMF inoculation), which enabled us to assess trait responses to growing conditions. Across treatments, the percentage of root trait variation explained by populations and continents was 9%–26%, compared to 7%–20% for leaf trait variation. From principal component analysis (PCA), the first PC axis for both root and leaf traits largely reflected plant size, while the second PC broadly captured mass allocation. Root mass allocation (PC 2) was related to mean annual temperature and mean moisture index, indicating that populations from cooler, wetter environments had longer, thinner roots. However, we found little support for a relationship between source environment and leaf trait PCs, root system size (PC1) or individual traits. Water availability and AMF inoculation effects on size were consistent among populations, with larger plants under AMF inoculation, and less mass allocation to leaves under lower water availability. Plantago lanceolata shows substantial population‐level variation in a suite of root traits, but that variation is only partially linked to the source environmental variables studied. Despite considerable differences in source abiotic environments, geographically separated populations have retained a strong and similar capacity for phenotypic plasticity both above and below‐ground. Read the free Plain Language Summary for this article on the Journal blog.

Variations in root architecture traits and their association with organ mass fraction of common annual ephemeral species in the desert of northern Xinjiang.

The variation of plant traits is closely related to the trade-offs between resource acquisition and conservation, as well as the accumulation of biomass. However, there has been a lack of comprehensive insights into the variation patterns, phylogenetic conservatism, and covariation with biomass allocation of root system architecture in desert areas. We examined the root systems of 47 annual ephemeral species and evaluated their biomass allocation and six key root system architecture traits. Our results indicated that the variation in root traits mainly originated from interspecific variation (48.78%-99.76%), but intraspecific variation should not be ignored as to why the contribution rate of root tissue density (RTD) reached 51.22%. The six root traits were mainly loaded on the first and second axes of the principal component analysis (PCA), these traits mainly vary along two dimensions. The highest interspecific variation is in RTD (51.63%) and the lowest in topological index (TI; 5.92%). The intraspecific variation value and range of specific root length (SRL), specific root area (SRA), and RTD were significantly higher than TI (p < .05), and they are not limited by phylogenetic relationships (0< K < 1, p > .05). The SRA is positively correlated with SRL (r = .72, p < .001) and negatively correlated with RTD (r = -.57, p < .05). The LMF is positively correlated with SRL, and SRA demonstrated the coordination between water consumption and acquisition. The positive correlation between RMF and MRD indicated the coordination of root carbon investment with exploring soil vertical space. The multi-dimensional variation of root traits, divergence of RTDs, and convergence of TI are important ecological strategies for annual short-lived plants to adapt to heterogeneous desert habitats. Meanwhile, these plants achieve optimal access to scarce resources through the high plasticity of resource acquisition (e.g., SRL and SRA) and conservation traits (e.g., RTD), as well as the trade-offs between them and organ mass fraction.

Transcriptomics Combined with Physiology and Metabolomics Reveals the Mechanism of Tolerance to Lead Toxicity in Maize Seedling.

Lead (Pb) exposure can induce molecular changes in plants, disrupt metabolites, and impact plant growth. Therefore, it is essential to comprehend the molecular mechanisms involved in Pb tolerance in plants to evaluate the long-term environmental consequences of Pb exposure. This research focused on maize as the test subject to study variations in biomass, root traits, genes, and metabolites under hydroponic conditions under Pb conditions. The findings indicate that high Pb stress significantly disrupts plant growth and development, leading to a reduction in catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activities by 17.12, 5.78, and 19.38%, respectively. Conversely, Pb stress led to increase malondialdehyde (MDA) contents, ultimately impacting the growth of maize. The non-targeted metabolomics analysis identified 393 metabolites categorized into 12 groups, primarily consisting of organic acids and derivatives, organ heterocyclic compounds, lipids and lipid-like molecules and benzenoids. Further analysis indicated that Pb stress induced an accumulation of 174 metabolites mainly enriched in seven metabolic pathways, for example phenylpropanoid biosynthesis and flavonoid biosynthesis. Transcriptome analysis revealed 1933 shared differentially expressed genes (DEGs), with 1356 upregulated and 577 downregulated genes across all Pb treatments. Additionally, an integrated analysis identified several DEGs and differentially accumulated metabolites (DAMs), including peroxidase, alpha-trehalose, and D-glucose 6-phosphate, which were linked to cell wall biosynthesis. These findings imply the significance of this pathway in Pb detoxification. This comprehensive investigation, employing multiple methodologies, provides a detailed molecular-level insight into maize's response to Pb stress.

Leaf and root traits are partially coordinated but they show contrasting multi-trait-based community trait dispersion patterns in a subtropical forest

Abstract The ecology of plant species relies on the synchronous functioning of leaves and roots, but few studies have simultaneously examined the community trait dispersion (CTD) patterns of both organs. We measured 16 analogous leaf and root traits on 44 co-occurring woody species in a subtropical forest in southern China, aiming to examine whether leaf and root traits were coordinated, organized into parallel trait axes, exhibited similar CTD, and displayed consistent responses in CTD and community-weighted means of (CWM) traits over environmental gradients. While the first axes of leaf and root trait variation similarly exhibited a fast–slow continuum, leaf traits covered a secondary “carbon economics” axis, contrasting to root traits depicting a collaboration axis reflecting species’ mycorrhizal dependency. Analogous leaf and root chemical traits were generally coordinated but less so for morphological traits. At the community level, changes in the CWM of the first axes were generally consistent among organs with more conservative traits found as increasing elevation but not for the second axis. While root traits became thinner and more conservative as soil phosphorus concentration decreased, leaf traits rarely varied. When different trait axes were combined, leaf traits were overdispersed but tended to converge with increased elevation and soil potassium and phosphorus levels, whereas root traits were clustered but tended to diverge along the same gradients. Our study highlights fine filtering of different suites of traits above- and belowground, which in turn might reduce overall niche overlap among species and promote coexistence with diverse functional designs.

Global root trait underrepresentation in Paleotropical communities: a qualitative analysis

Many ecosystem processes revolve around plant roots and the rhizosphere, but root trait knowledge has generally lagged behind aboveground plant traits from leaves and stems. In particular, root trait representation of Paleotropical species and tropical communities in modern trait databases remains poor, constraining our understanding of belowground processes in these regions. Therefore, we sought to examine the current state of root trait representation and associated topics in the Paleotropics to identify gaps and biases in the existing literature. Using an exhaustive literature scan, we compiled a list of publications that contained various belowground trait information. Subsequently, we utilized a statistical topic modeling method to analyze abstracts of publications in order to identify topics studied alongside root trait documentation. Finally, we consolidated trends in root trait coverage and topics across five geographical regions and four time periods to illustrate shifts in literature and knowledge of ecological processes revolving around roots. Root trait representation was heavily biased toward root biomass but other aspects of root systems such as physiology, architecture and anatomical traits remain underrepresented. We categorized 23 unique topics around root trait literature across eight categories: ecosystem productivity and biomass stocks, plant functional traits, resource availability, ecosystem processes and dynamics, mycorrhizal colonization, edaphic processes, seedling experiments, and global change and variation. Traits and topic coverage were unequally distributed across the Paletropics and exhibited a notable shift in focus from resource limitation and mycorrhizae research to root trait variation at large spatial and temporal scales over the last 50 years of root trait literature. Given these trends and the heterogenous effects global change exerts on the tropics at a regional scale, we provided several recommendations to facilitate inter-study comparisons of traits to advance the field’s understanding of belowground ecosystem processes in pantropical communities.

Influence of Incremental Short Term Salt Stress at the Seedling Stage on Root Plasticity, Shoot Thermal Profile and Ion Homeostasis in Contrasting Wheat Genotypes

Understanding the component traits determining salt stress tolerance is a major breeding target in wheat. The lack of genetic resources suited to salt-affected regions and the complexity of the traits involved impede progress in breeding salt-tolerant wheat varieties. This study was conducted with four bread wheats, namely (Triticum aestivum) Kharchia-65 (K-65), BT-Schomburgk (BTS), HD-2687, and HD-3298. Treatments were imposed on plants with varying electrical conductivity (control, 5 dS m−1, 10 dS m−1, and 15 dS m−1) with a combination of three different salts NaCl, CaCl2·2H2O, and Na2SO4. We evaluated variations in root system architecture, canopy temperature (depicted as a thermal image), reactive oxygen species (ROS) homeostasis, and leaf stomatal density in response to incremental doses of salt stress in a hydroponic experiment. As the plants were sampled after short-term exposure to stress (within 3 weeks of stress imposition), the plants were expected to be in a quiescent state. Due to the osmotic effect, the growth of the plants was compromised, and the associated decrease in stomatal conductance increased the canopy temperature. ROS accumulation and antioxidant enzyme activity did not follow a definite pattern. The antioxidant system’s tolerance to ROS comes into action much later in the tolerance mechanism. That could probably be the reason behind the varied response in ROS accumulation and antioxidant enzymes after short-term exposure to salt stress. Thermal images could effectively differentiate between salt-tolerant (K65) and sensitive (HD2687) genotypes. The variation in Na+/K+ ratio also suggested a genotypic variation in salt tolerance. The genotypes of K-65 maintained a better root system, while HD2687 showed severe reduction in root biomass and other root traits under salt stress. The PCA data also point out genotypic variation in lateral and main root traits in response to different salt stress levels. For salt tolerance in wheat, the main contributing root traits were total root length, total surface area, total root volume, tips, and other main, lateral root traits. The idea of differential control of RSA dynamics is novel and can be further explored to understand natural variation in salt stress tolerance.

Root Morphological Characteristics of Five Rice Genotypes with Different Nitrogen Use Efficiency

While nitrogen (N) uptake in rice has been extensively studied, the influence of root morphology on this process is not fully elucidated. This study explores the root morphological characteristics and N uptake of five diverse rice genotypes under different N sources, including novel slow-release nanoclay polymer/biopolymer composite (NCPC/NCBPC) fertilizers. A greenhouse experiment was conducted using five diverse rice genotypes (Swarna, Pusa Basmati-1, Pusa-44, MTU1010 and Nagina-22) with five N treatments (T1- control (without N fertilizer), T2- 100% RDF of N through urea, T3- 75% RDF of N through urea loaded NCPC, T4- 75% RDF of N through urea loaded NCBPC-I (NCBPC prepared with wheat flour), T5- 75% RDF of N through urea loaded NCBPC-II (NCBPC prepared with maida)). The results of the study revealed that maximum overall root growth was recorded under Pusa Basmati-1 followed by Swarna, MTU 1010, Nagina-22 and Pusa-44. Among the N treatment, maximum root growth and N uptake was recorded under NCPC treatment followed by NCBPC-II, NCBPC-I, urea and control. Thus, the study reveals significant variations in root traits among genotypes and N treatments, with notable improvements observed under NCPC and NCBPC based N treatments.

Do phylogenetic and environmental factors drive the altitudinal variation in absorptive root traits at the species and community levels?

Do phylogenetic and environmental factors drive the altitudinal variation in absorptive root traits at the species and community levels?

Species phylogeny, ecology, and root traits as predictors of root exudate composition.

Root traits including root exudates are key factors affecting plant interactions with soil and thus play an important role in determining ecosystem processes. The drivers of their variation, however, remain poorly understood. We determined the relative importance of phylogeny and species ecology in determining root traits and analyzed the extent to which root exudate composition can be predicted by other root traits. We measured different root morphological and biochemical traits (including exudate profiles) of 65 plant species grown in a controlled system. We tested phylogenetic conservatism in traits and disentangled the individual and overlapping effects of phylogeny and species ecology on traits. We also predicted root exudate composition using other root traits. Phylogenetic signal differed greatly among root traits, with the strongest signal in phenol content in plant tissues. Interspecific variation in root traits was partly explained by species ecology, but phylogeny was more important in most cases. Species exudate composition could be partly predicted by specific root length, root dry matter content, root biomass, and root diameter, but a large part of variation remained unexplained. In conclusion, root exudation cannot be easily predicted based on other root traits and more comparative data on root exudation are needed to understand their diversity.

Weak phylogenetic and habitat effects on root trait variation of 218 Neotropical tree species

IntroductionTropical forests harbor a large diversity of closely related tree species that can thrive across habitats. This biodiversity has been found to correspond to large functional diversity in aboveground traits, and likely also relates to belowground trait variation. Globally, root trait (co-)variation is driven by different belowground resource strategies of species, environmental variation, and phylogeny; however, these patterns mostly reflect observations from temperate biomes and remain unconfirmed in tropical trees. We examine phylogenetic and environmental effects on root trait (co-)variation of trees across habitats in an Amazonian rainforest.MethodsRoots of 218 tree species from ten dominant families were sampled across three major habitats near Manaus, Brazil. We quantified five morphological and architectural root traits to (i) investigate how they reflected different resource strategies across species, (ii) compare them between families and superorders to test phylogenetic effects, and (iii) compare them between habitats to determine environmental effects on root trait expressions and variability.ResultsRoot traits discriminated species along a tradeoff between root diameter and root branching and, secondly, due to variation in root tissue density. Our results further show weak phylogenetic effects on tropical tree root variation, for example, families from the same superorder showed large divergence in their root traits, while those from different superorders often overlapped in their root morphology and architecture. Root traits differed significantly between habitats but habitat type had only little effect on overall root trait variation.DiscussionOur work suggests that the dimensions and drivers that underlie (co-)variation in tropical root traits may differ from global patterns defined by mostly temperate datasets. Due to (a)biotic environmental differences, different root trait dimensions may underlie the belowground functional diversity in (Neo)tropical forests, and we found little evidence for the strong phylogenetic conservatism observed in root traits in temperate biomes. We highlight important avenues for future research on tropical roots in order to determine the degree of, and shifts in functional diversity belowground as communities and environments change in tropical forests.

Root traits of grasslands rapidly respond to climate change, while community biomass mainly depends on functional composition

Abstract Current challenges of functional responses in plant communities to climate change call for multi‐factorial experiments. Moreover, studies on climate change should focus on below‐ground responses since absorptive roots largely control soil C allocation and resource acquisition. Thus, we aimed to understand biomass allocation and traits of absorptive roots in young mesocosm grasslands subjected to simultaneous manipulation of three components of climate change. We tested grassland biomass and root traits under climate change while manipulating functional composition. Using 64 mesocosms with designed grasslands within four chambers of a controlled‐environment facility (‘ecotron’), we simulated two contrasting IPCC climate change scenarios for elevated [CO2] and temperature (‘eCO2’ and ‘eT’). We applied normal vs. reduced precipitation of early summer in Central Europe. We also tested the effect of functional composition by varying the proportion of grasses and forbs in the communities. Specifically, we quantified above‐ and below‐ground biomass, root diameter (RD), root tissue density (RTD), specific root length (SRL), and root length density (RLD). Functional composition played a significant role in biomass allocation of the grasslands, with grass‐dominated communities producing more below‐ground biomass than forb‐dominated ones, and the opposite pattern registered above‐ground. Below‐ground biomass did not respond to climate change factors, whereas root trait values responded significantly during early establishment of the grasslands. A higher RD indicated a more conservative strategy under reduced precipitation, while eT and eCO2 led to higher RTD. We detected interactive effects between climate change and functional composition on root traits. Moreover, root biomass primarily occupied the upper soil layer, while a warm and CO2‐rich environment promoted root allocation to the lower soil layer. Grass‐dominated communities quickly colonized all available soil volume, while forb‐dominated ones accumulated more root biomass in the upper soil layer. In the mesocosm grasslands, root trait variation rather than root biomass reflected below‐ground adjustments to climate change. Furthermore, functional composition and the associated trait diversity modulated biomass allocation. Thus, establishing plant communities that are more resilient to climate change must consider the functional and taxonomic composition of the seed mixtures designed to restore urban grasslands. Read the free Plain Language Summary for this article on the Journal blog.

Root trait variation along water gradients in the Cape Floristic Region

AbstractQuestionsRoots are responsible for essential plant functions including water uptake. However, the extent to which root traits (size and structure) determine plant presence in water‐limited environments is still poorly understood. Here we investigated how root traits vary across water availability gradients within a dry South African biome.LocationSouth Africa.MethodsWe measured six below‐ground (root) and eight above‐ground (leaf + stem) traits of 124 individuals of nine dominant woody shrub species from wetter and drier sites (600–700 vs 250–300 mm annual precipitation) in the Fynbos biome of the Cape Floristic Region. Within sites, we sampled from recently burnt and unburnt/more mature vegetation and at three locations along topographical gradients.ResultsDrier regions showed greater maximum rooting depth, length, root dry matter content and root to shoot ratio. These trait patterns were consistent at an intraspecific level, along locally drier topographical locations and in post‐fire environments. Roots accounted for significant whole‐plant trait variation. Additionally, in drier conditions, we found increased root allocation deviating from expected global allometric relationships. Our study also demonstrates that the combination of fire and drought in the driest locations results in poor above‐ground vegetation recovery in terms of plant size, cover and individual counts with only resprouters persisting.ConclusionsOur research suggests that root investment in Fynbos shrubs will likely be key for coping with a drier and warmer future and should be a focus of more research for dryland biomes.

Root morphological and physiological traits are committed to the phosphorus acquisition of the desert plants in phosphorus-deficient soils

BackgroundPhosphorus (P) deficiency in desert ecosystems is widespread. Generally, desert species may allocate an enormous proportion of photosynthetic carbon to their root systems to adjust their P-acquisition strategies. However, root P-acquisition strategies of deep-rooted desert species and the coordination response of root traits at different growth stages to differing soil P availability remains unclear. In this study, a two-year pot experiment was performed with four soil P-supply treatments (0, 0.9, 2.8, and 4.7 mg P kg–1 y–1 for the control, low-, intermediate-, and high-P supply, respectively). Root morphological and physiological traits of one- and two-year-old Alhagi sparsifolia seedlings were measured.ResultsFor two-year-old seedlings, control or low-P supply significantly increased their leaf Mn concentration, coarse and fine roots’ specific root length (SRL), specific root surface area (SRSA), and acid phosphatase activity (APase), but SRL and SRSA of one-year-old seedlings were higher under intermediate-P supply treatment. Root morphological traits were closely correlated with root APase activity and leaf Mn concentration. One-year-old seedlings had higher root APase activity, leaf Mn concentration, and root tissue density (RTD), but lower SRL and SRSA. Two-year-old seedlings had higher root APase activity, leaf Mn concentration, SRL and SRSA, but a lower RTD. Root APase activity was significantly positively correlated with the leaf Mn concentration, regardless of coarse or fine roots. Furthermore, root P concentrations of coarse and fine roots were driven by different root traits, with root biomass and carboxylates secretion particularly crucial root traits for the root P-acquisition of one- and two-year-old seedlings.ConclusionsVariation of root traits at different growth stages are coordinated with root P concentrations, indicating a trade-off between root traits and P-acquisition strategies. Alhagi sparsifolia developed two P-activation strategies, increasing P-mobilizing phosphatase activity and carboxylates secretion, to acclimate P-impoverished in soil. The adaptive variation of root traits at different growth stages and diversified P-activation strategies are conducive to maintaining the desert ecosystem productivity.

Effects of root litter traits on soil organic matter dynamics depend on decay stage and root branching order

Decaying roots contribute disproportionately to soil organic carbon (SOC) stocks in many ecosystems, yet few studies have examined the afterlife effects of root trait variability on the formation, stability and mineralization of SOC. In order to assess how root functional class (absorptive vs. transport) and mycorrhizal association (ectomycorrhizal vs. arbuscular mycorrhizal fungi) affect both formation and loss of SOC, we decayed lower-order absorptive (orders 1–2) and higher-order transport (orders 3–4) roots from six arbuscular mycorrhizal (AM) and six ectomycorrhizal (EcM) associated hardwood tree species in an isotopically distinct soil under laboratory conditions. We found that root litter effects on SOC differed significantly among root functional classes and mycorrhizal types. AM absorptive and transport roots (high in nitrogen and soluble compounds) contributed more to the formation of new mineral-associated organic carbon (MAOC), but also contributed to higher mineralization of native SOC (via priming effects). Moreover, absorptive AM roots formed MAOC gradually and rates saturated, whereas ECM roots formed MAOC more quickly, despite slower decay (via greater formation efficiency). Together, these findings demonstrate how different combinations of root traits might contribute to soil C balance, and that failure to account for the chemical and morphological heterogeneity of roots, as well their interactions with microbes over time, may lead to incorrect projections of SOC stocks and turnover.

Root traits of perennial C4 grasses contribute to cultivar variations in soil chemistry and species patterns in particulate and mineral‐associated carbon pool formation

AbstractRecent studies have indicated that the C4 perennial bioenergy crops switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii) accumulate significant amounts of soil carbon (C) owing to their extensive root systems. Soil C accumulation is likely driven by inter‐ and intraspecific variability in plant traits, but the mechanisms that underpin this variability remain unresolved. In this study we evaluated how inter‐ and intraspecific variation in root traits of cultivars from switchgrass (Cave‐in‐Rock, Kanlow, Southlow) and big bluestem (Bonanza, Southlow, Suther) affected the associations of soil C accumulation across soil fractions using stable isotope techniques. Our experimental field site was established in June 2008 at Fermilab in Batavia, IL. In 2018, soil cores were collected (30 cm depth) from all cultivars. We measured root biomass, root diameter, specific root length, bulk soil C, C associated with coarse particulate organic matter (CPOM) and fine particulate organic matter plus silt‐ and clay‐sized fractions, and characterized organic matter chemical class composition in soil using high‐resolution Fourier‐transform ion cyclotron resonance mass spectrometry. C4 species were established on soils that supported C3 grassland for 36 years before planting, which allowed us to use differences in the natural abundance of stable C isotopes to quantify C4 plant‐derived C. We found that big bluestem had 36.9% higher C4 plant‐derived C compared to switchgrass in the CPOM fraction in the 0–10 cm depth, while switchgrass had 60.7% higher C4 plant‐derived C compared to big bluestem in the clay fraction in the 10–20 cm depth. Our findings suggest that the large root system in big bluestem helps increase POM‐C formation quickly, while switchgrass root structure and chemistry build a mineral‐bound clay C pool through time. Thus, both species and cultivar selection can help improve bioenergy management to maximize soil carbon gains and lower CO2 emissions.

Phenotypic Variability for Root Traits in Andean Common Beans Grown with and without Aluminum Stress Conditions

Genetic variation in wild relatives, GenBank accessions, landraces, and cultivars can unlock key alleles for the traits of interest for breeding programs. Breeding programs often utilize different strategies to quantify the source of heritable variation for target traits. One neglected area of study is the root traits of diverse genotypes, and this is especially the case for aluminum toxicity effects on legumes such as the common bean, which is the most used pulse for direct human consumption. This study evaluated 267 genotypes of common bean that were part of the global Andean Diversity Panel (ADP), consisting mainly of genotypes assembled from public and private breeding programs in Africa and North America, as well as elite lines and land races from the USDA. The ADP was evaluated for root traits at the seedling stage in the Tennessee State University (TSU) greenhouse using a hydroponic system with a standard nutrient solution with and without aluminum (Al). The recorded data on the roots per trial were fit to a linear mixed model for the analysis of variance in order to test for the genotype differences. Adjusted means considered replication and blocks within replication as random effects and genotypes as fixed effects. These were then used for Pearson correlation tests and for principal component analysis (PCA), where the first two vectors accounted for 94.5% and 93% of the explained variation under the control and Al-treatment conditions, respectively. Genotypes were clustered based on the morphology of roots in response to Al-toxicity treatment using the Euclidean distance and Ward’s hierarchical agglomerative clustering method, identifying four distinctive groups significant at p &lt; 0.01. The intra-cluster distance was lower than the inter-cluster distances, which indicated a heterogeneous and homogeneous nature between and within clusters, respectively. The results suggest that crossing between accessions from two of the clusters would result in the maximum genetic segregation. One cluster was found to have a higher Al-toxicity tolerance than the others.

Coordinated variation in root and leaf functional traits of Hippophae rhamnoides treated at different stump heights in feldspathic sandstone areas of Inner Mongolia.

This study was aimed to clarify the effects of stumping on root and leaf traits as well as the tradeoffs and synergies of decaying Hippophae rhamnoides in feldspathic sandstone areas, and to select the optimal stump height that contributed to the recovery and growth of H. rhamnoides. variations and coordination between leaf traits and fine root traits of H. rhamnoides were studied at different stump heights (0, 10, 15, 20cm, and no stumping) in feldspathic sandstone areas. All functional traits of the leaves and roots, except the leaf C content (LC) and the fine root C content (FRC), were significantly different among different stump heights. The total variation coefficient was the largest in the specific leaf area (SLA), which is therefore the most sensitive trait. Compared to non-stumping, SLA, leaf N content (LN), specific root length (SRL) and fine root N content (FRN) all improved significantly at stump height of 15cm, but leaf tissue density (LTD), leaf dry matter content (LDMC), leaf carbon to nitrogen ratio (LC : LN), fine root tissue density (FRTD), fine root dry matter content (FRDMC) and fine root carbon to nitrogen ratio (FRC : FRN) all decreased significantly. The leaf traits of H. rhamnoides at different stump heights follow the leaf economic spectrum, and the fine roots show a similar trait syndrome to the leaves. SLA and LN are positively correlated with SRL and FRN and negatively with FRTD and FRC : FRN. LDMC and LC : LN are positively correlated with FRTD and FRC : FRN, and negatively correlated SRL and RN. The stumped H. rhamnoides changes to the 'rapid investment-return type' resource trade-offs strategy, and the growth rate is maximized at the stump height of 15cm. Our findings are critical to the prevention and control of vegetation recovery and soil erosion in feldspathic sandstone areas.

武夷山不同海拔毛竹细根功能性状

PDF HTML阅读 XML下载 导出引用 引用提醒 武夷山不同海拔毛竹细根功能性状 DOI: 10.5846/stxb202112143536 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32071555）；福建省科技厅产学合作项目（2019N5009）；福建省教育厅项目（JAT190084） Fine root traits of Phyllostachys edulis at different altitudes in Wuyi Mountain Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:细根作为植物最重要的资源获取功能器官，是影响陆地生态系统的重要组成部分。定量化毛竹的细根功能性状对于理解其生理生态特征响应及生活史策略至关重要。为揭示毛竹细根功能性状随海拔梯度的变化规律以及细根的适应策略，对武夷山不同海拔（840 m、1040 m、1240 m）毛竹细根的碳（C）、氮（N）、磷（P）含量和比根长（SRL）、比根面积（SRA）等性状进行测定，分析细根性状在海拔上的差异及其异速生长关系。结果表明：（1）不同海拔毛竹细根养分性状存在显著差异。毛竹细根C含量在海拔1040 m最大。随海拔升高，细根N、P含量均呈下降趋势，细根C ： N、C ： P随着海拔的升高而增加。（2）细根的结构性状在海拔梯度上差异显著。随海拔升高，细根平均根直径（AvgDiam）、SRL及SRA均呈下降趋势，而根组织密度（RTD）呈升高趋势。（3）细根性状间存在显著的异速生长关系。细根N与P含量存在显著的等速生长关系，二者与C含量存在显著异速生长关系；SRL与SRA存在显著的等速生长关系，二者与RTD存在显著的负等速生长关系，与N含量存在显著的异速生长关系；细根AvgDiam与RTD存在显著的负异速生长关系。毛竹细根功能性状海拔梯度差异显著且细根性状之间呈显著的异速生长关系，表明毛竹细根获取型性状（如SRL）与保守型性状（如RTD）存在权衡，在海拔840 m毛竹倾向于增加根长来获取养分和水分，随海拔升高则采取保守策略，如增加根组织密度。因此，毛竹能够通过自身表型可塑性机制合理权衡细根性状之间的资源配置以适应环境变化。 Abstract:As the most important resource-obtaining functional organ of plants, fine roots are an important part affecting terrestrial ecosystems. Quantifying the fine root functional traits of Phyllostachys edulis is critical to our understanding of the physiological response and ecological characteristics for bamboo's life-history strategies. To investigate the variation of fine root traits of Phyllostachys edulis with altitude gradient and the adaptation strategies of fine roots, the contents of carbon (C), nitrogen (N), phosphorus (P), specific root length (SRL), specific root area (SRA) and other traits of Ph.edulis's fine roots were measured in Wuyi Mountain at different altitudes (840 m, 1040 m, 1240 m), and the differences of fine root traits at different altitudes and the allometric relationship between them were analyzed. The results showed that:(1) there were significant differences in the contents of C, N, P and the ecological stoichiometry among different altitudes. The content of C in fine roots was the highest at the altitude of 1040 m, with the increase in altitude, the content of N and P decreased, leading to the increase of the ratio of C:N and C:P. (2) There were significant differences on the structural traits of fine roots among different altitudes. As the altitude increased, the average root diameter (AvgDiam), SRL, SRA of fine roots all showed a downward trend, while the root tissue density (RTD) showed an upward trend. (3) There was a significant allometric relationship between fine root traits. The significant isometric relationships were found between N and P content in fine roots, but they showed a significant allometric relationship between C content. There was a significant isometric relationship between SRL and SRA, but they showed a significantly negative isometric relationship with RTD, and showed a significant allometric relationship with N content. The significantly negative allometric relationships were found between AvgDiam and RTD. There was a significant difference of fine root functional traits among different altitudes, and a significant allometric relationship between them. Our research showed that there was a trade-off between fine root acquisitive traits (such as SRL) and conservative traits (such as RTD). Ph.edulis tended to increase root length for increasing nutrient absorption at altitude of 840 m, and adopted the conservative strategy (such as increasing root tissue density) with increasing altitude. Therefore, Ph.edulis can rationally balance resource allocation among fine root traits to adapt to environmental changes through phenotypic plasticity mechanism. 参考文献 相似文献 引证文献