Search Results (107)

Calibrating the mutagenic dose is the first practical step of any radiation mutation-breeding programme, and it is usually summarised by the median lethal dose (LD50) or the median growth-reduction dose (GR50). We asked whether an accessible, image-based phenotyping pipeline can quantify the early radiation response of cowpea (Vigna unguiculata L. Walp.) seedlings finely enough to estimate GR50 and to rank organ- and pigment-level sensitivities. Seeds of the traditional Paraguayan landrace kumandá pyta’i were exposed to Cobalt-60 gamma rays at 0, 100, 200, 300, 400, 500, 600, and 700 Gy, grown in a greenhouse, and photographed at the early seedling stage. A single calibrated photograph (5.1 px mm⁻¹) of 83 seedlings was segmented in Fiji/ImageJ 1.54p and analysed with Python to extract morphometric traits (total, root, and shoot length, root:shoot ratio, tortuosity, and a two-dimensional biomass proxy) and colorimetric traits (CIE L*a*b*, a normalised greenness index, and colour-class pixel fractions). Because the data departed from normality, dose effects were tested with Kruskal–Wallis, Spearman rank correlation, and Dunn post hoc tests, and GR50 was estimated by regression of each trait expressed as a percentage of the control. Total length, shoot length, and the biomass proxy declined significantly with dose (Spearman ρ = −0.40, −0.51, and −0.47; all p < 0.001), preceded by a low-dose stimulation at 100 Gy. Estimated GR50 values were ≈390 Gy for shoot length, ≈510 Gy for total length, and ≈550 Gy for the biomass proxy, within the range reported for other cowpea genotypes. Shoot elongation was more radiosensitive than root elongation, so the root:shoot ratio did not decline; tortuosity showed no dose response. Among pigment traits, the loss of greenness was the most robust signal (a* increased, ρ = +0.62, p = 5 × 10⁻¹⁰; green pixel fraction fell from 0.32 to near zero by 500 Gy). These results show that single-photograph phenotyping resolves a coherent, statistically supported dose response and yields a GR50 estimate usable for dose calibration. For kumandá pyta’i, doses of roughly 300–400 Gy (below GR50) are the most defensible starting window for mutation induction. The framework is reproducible and low-cost, but it is based on one greenhouse experiment and a single genotype, and should be validated across independent trials and cultivars. Full article

Fresh ginseng is a high-value medicinal root crop whose postharvest quality is affected by field heterogeneity, washing, packaging, and storage. This study evaluated two packaging films—50 µm polyethylene (PE50) and a 30 µm polyethylene/30 µm oriented polypropylene laminate (PE30/OPP30)—and a post-wash 80 ppm peracetic acid (PAA) spray applied at 20 °C at approximately 60 mL kg⁻¹ fresh root mass. Field-sorted six-year-old roots from one commercial ridge were stored at −2 °C for 14 weeks. The primary factorial design comprised film and PAA treatment, while farmer grade class was retained as a stratification factor and tissue position as a within-root factor for destructive analyses. Package atmosphere, post-storage ambient CO₂ evolution, cumulative weight loss, tissue moisture, color and visual marketability, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, total phenolic content (TPC), and targeted liquid chromatography (LC) quantification of Rg1 and Rb1 were evaluated using three independent biological replicates. PE30/OPP30 generated lower O₂ and higher CO₂ than PE50 and reduced cumulative weight loss; however, O₂ reached 0.63% and CO₂ reached 14.04% at 4 weeks, indicating potentially hypoxic conditions. PAA did not consistently improve the measured physicochemical traits, and microbial efficacy was not evaluated. Fine roots showed the lowest moisture status but the highest Rg1 and Rb1 contents. These findings provide a single-field baseline for integrating packaging response, tissue water status, and chemical markers, but require validation across production sites, seasons, and packaging-film types before broad commercial application. Full article

This study examined the influence of arbuscular mycorrhizal fungi (AMF) on root system development of the invasive Nicotiana glauca Graham (Solanaceae) under intraspecific competition. Seedlings were grown with or without AMF inoculation at four planting densities (1–4 plants per pot) in a factorial experiment arranged in a completely randomized design under greenhouse conditions. After six months, shoot and root fresh and dry biomass were measured, along with root-to-shoot ratio. Root morphological traits, including total root length, surface area, volume, mean diameter, and number of root tips, were quantified and further analyzed across five levels of root diameter (0–1 mm at 1 mm intervals). Root nitrogen, phosphorus and potassium content, AMF colonization, and spore density were also assessed. Results showed that all measured traits of non-mycorrhizal seedlings declined markedly with increasing plant density. In contrast, AMF-inoculated seedlings maintained higher root biomass, total root length, surface area, and root tip numbers, particularly at low density. Across all treatments, roots < 1 mm contributed the highest proportion of total root length, surface area, and tip number, with AMF significantly enhancing these fine-root traits. Mycorrhizal seedlings also exhibited higher root-to-shoot ratios and improved N, P, and K content compared to non-inoculated controls. Multivariate analyses further indicated that AMF inoculation was the primary factor structuring root trait variation across planting densities. Overall, AMF inoculation promoted a finer and more extensive root system under increasing intraspecific competition, indicating a key role in enhancing resource acquisition and potentially supporting the competitive ability and invasiveness of N. glauca. Full article

Strip cutting enables efficient, low-cost harvesting and regeneration of abandoned bamboo stands with minimal disturbance to the ecosystem. Nevertheless, the growth and resource allocation mechanisms of Indocalamus latifolius (Keng) McClure in response to varying strip cutting intensities remain unclear. In this study, abandoned I. latifolius stands were selected as research materials, with four gradient widths of cutting strips established (0 m, 1 m, 2 m, 3 m). This study aimed to clarify the growth and resource allocation mechanisms of I. latifolius in response to strip cutting by measuring organ biomass accumulation, root morphological traits, and the allocation strategies for nutrients and non-structural carbohydrates in cutting and reserved strips under different strip cutting intensities. The results showed that the 1 m strip width facilitated new ramet growth in both cutting and reserved strips, while the 2 m strip width only promoted new ramet growth in reserved strips. Both treatments suppressed fine root proliferation and increased average root diameter. Strip cutting significantly elevated nitrogen and phosphorus contents in new leaves, new stems, rhizomes, and roots, as well as soluble sugar contents in new leaves and new stems across cutting and reserved strips. By contrast, it reduced the non-structural carbohydrate content in roots, as well as nitrogen and phosphorus contents in old stems and old leaves within reserved strips. The 1 m and 2 m strip cutting treatments increased the nitrogen and phosphorus allocation ratios of new leaves, new stems, and rhizomes in reserved strips, and reduced the allocation ratios in roots, old leaves, and old stems. In conclusion, moderate-intensity strip clear-cutting facilitates new ramet sprouting within cutting strips and induces compensatory leaf growth in reserved strips. I. latifolius preferentially allocates nutrients and non-structural carbohydrates to new leaves, new stems, and rhizomes in reserved strips, yet this resource allocation strategy inhibits root growth. Full article

To clarify the effects of pond excavation and field elevation combined with biochar application on soil improvement and maize growth in cold-soaked fields in northern China, a two-year field experiment was conducted using maize as the test crop under five biochar application rates: 0, 7.5, 15, 22.5, and 30 t/ha. The effects of biochar application on soil water characteristics, maize root development, plant growth, and yield formation were investigated. The results showed that, under the pond excavation and field elevation treatment, the application of 22.5 t/ha biochar (B3) achieved the best overall improvement effect and significantly improved soil moisture conditions. At the heading stage, the soil water content in the 0–90 cm soil layer under the B3 treatment increased by 6.18% and 27.72% in the two experimental years, respectively, compared with the 0 t/ha biochar treatment (B0). In 2025, compared with the B0 treatment, root length density, root surface area density, and root volume density under the B3 treatment increased by 38.56%, 109.31%, and 65.35%, respectively, while the average diameter of maize fine roots decreased by 8.50%. Meanwhile, the leaf area index, plant height, stem diameter, kernels per ear, 100-kernel weight, and maize yield were all significantly increased, with grain yield reaching 13,991.10 kg/ha in 2025. Correlation analysis showed that the biochar application rate was significantly positively correlated with maize plant height, stem diameter, leaf area index, root morphological traits, and grain yield, indicating that biochar application promoted maize growth and yield by optimizing canopy structure and root architecture. These results demonstrate that pond excavation and field elevation combined with an appropriate biochar application rate can effectively improve cold-soaked fields in northern China and achieve stable and high maize yields, thereby providing technical support for the management of medium- and low-yield farmlands. Full article

Primary succession following glacier retreat provides a natural system for testing whether soil development simply shifts fine roots along a single acquisitive–conservative axis orinstead changes the nutrient-acquisition pathway that dominates at the community level. We hypothesized a stage-dependent sequence, from substrate-limited exploration, to transient morphological capture, and finally to rhizosphere-mediated biochemical mobilization. To test this idea, we quantified fine-root morphology, absorptive-transport partitioning, anatomy, phosphatase activity, exudation, community-scale belowground structure, and soil and rhizosphere properties across woody communities representing approximately 20, 40, and 90 years since deglaciation in the Hailuogou Glacier foreland. Across succession stages, bulk density and pH declined, whereas field capacity, soil carbon, and soil nitrogen increased, indicating rapid development of the belowground resource environment. Fine-root strategies did not fall along a single acquisitive–conservative continuum. Instead, morphological nutrient capture peaked at intermediate succession: the 40-year stage had the highest specific root length, specific root area, absorptive-to-transport root length ratio, and root nitrogen concentration. In contrast, the 90-year stage showed lower specific root length but higher dry matter content, thicker cortex, greater standing fine-root biomass, larger rhizosphere volume, higher phosphatase activity, and greater area-based carbon exudation. This late-successional syndrome coincided with stronger extracellular enzyme activity, larger dissolved organic carbon and nitrogen pools, and higher microbial biomass, despite negative net nitrogen mineralization. Species-level analyses showed that biochemical-input traits were jointly shaped by successional stage, species identity, and their interaction. Together, these results show that primary succession did not simply increase or decrease root acquisitiveness. Instead, as soils developed, it changed the nutrient-acquisition pathway that dominated, with direct implications for nutrient cycling and vegetation dynamics in rapidly developing glacier-foreland ecosystems. Full article

Using native tree species, the phytostabilisation of toxic metals at former mining and industrial sites can provide ways to prevent metal spread and leaching into the environment and bring the sites back into the economic circuit. In this study, mixed afforestations with young trees from seven Central European species showing contrasted autecology (Picea abies (L.) Karst, Fagus sylvatica L., Acer pseudoplatanus L., Alnus incana (L.) Moench, Populus tremula L., Salix viminalis L. and Betula pendula Roth) were exposed during five years to mixed soil contamination (Zn/Cu/Pb/Cd = 1349/317/70/8 mg kg⁻¹). The uptake and allocation of the metals in root and shoot tissues, various functional traits and nutrient responses were compared. Despite high metal availability, all tree species showed low metal uptake and similar metal concentrations in their roots. The mobile metals (Zn, Cd) accumulated in the shoot and foliage of early-successional species with acquisitive ecological strategy only, whereas the late-successional species blocked the transfer of all metals from the roots to the aboveground organs. All species showed good tolerance to metal contamination, with large interspecific differences regarding the biomass production and some nutrient concentrations, in apparent relation to the varying species’ ecological strategies and independent of the metal treatment. Zn allocation within fine root tissues could enhance transient spatial and temporal metal immobilisation, especially when associated with protective or defence structures, which also contributed to metal detoxification. Higher transfer of mobile metals to aboveground organs in pioneer tree species was clearly related to their acquisitive ecological strategies, in the context of higher nutrient demand in foliage and lesser defence and protection of vegetative organs. The implications of findings for phytostabilisation applications are discussed. Full article

Soil nutrients and water are often distributed heterogeneously in space, yet how plant roots forage in response to such heterogeneity and how their strategies relate to functional traits remain poorly understood. Here, we conducted an indoor pot experiment manipulating water and nutrient supply in both homogeneous and heterogeneous patch patterns using seedlings of four tree species, focusing on root functional traits and foraging strategies. The results indicate that root foraging behavior exhibits both resource specificity and species specificity: roots tend to proliferate toward nutrient-rich and low-water patches as an adaptive strategy. Although no strict dichotomy was observed between high foraging scale (low precision) and low foraging scale (high precision) strategies under heterogeneous conditions, fine-rooted species (Acer truncatum and Koelreuteria paniculata) exhibited traits leaning toward “precise foraging”, whereas coarse-rooted species (Prunus davidiana and Quercus variabilis) tended toward a conservative “random walk” pattern, with no trade-off between root foraging scale and precision. Root morphological traits exerted significant nonlinear regulation on foraging scale: root biomass foraging scale (FS_RB) correlated positively with root diameter (RD) but negatively with specific root length (SRL) and specific root area (SRA); root length foraging scale (FS_RL) correlated positively with root length (RL), root tip number (RTN), SRL, and SRA. In contrast, root morphological traits could not explain the variation in foraging precision, suggesting that foraging precision constitutes another distinct dimension in root-trait space. In summary, this study provides key insights into the foraging strategies of plant roots in heterogeneous environments, expanding our understanding of the multidimensionality of root functional traits. Full article

The mechanisms through which forest thinning influences the fine root foraging strategies of coexisting tree species in mixed forests remain unclear, limiting our ability to manage mixed forests for long-term productivity. We employed a space-for-time substitution approach in a Qinling pine-oak forest, in which fine roots of Pinus tabuliformis (Pt) and Quercus aliena var. acuteserrata (Qa) were sampled from unthinned plots and plots thinned 6 years (transient phase) and 14 years (persistent phase) prior, respectively. We analyzed the morphological and chemical traits of both absorptive and transport fine roots (0–20 cm depth) to decipher their distinct adaptation strategies. The results showed that Pt enhanced morphological plasticity in both absorptive and transport roots at T₂₀₁₀ (e.g., specific root length: +44% and 37%, p < 0.05). In contrast, Qa showed minimal changes in absorptive root morphology and chemistry (p > 0.05). Redundancy analysis indicated that thinning intensified functional divergence in root strategies between the two tree species and between the two root functional types (i.e., absorptive vs. transport fine roots). Hierarchical variance partitioning analysis indicated that root functional type was the primary driver (51.9%), with tree species identity (Pt vs. Qa) and thinning practices being secondary. Critically, soil properties significantly shaped absorptive root traits (explaining 10.4% of the variance) but did not affect transport root traits, whereas thinning was a dominant factor for transport roots (21.6%). This insight enables the tailoring of silvicultural interventions to tree species-specific foraging strategies, optimizing belowground resource acquisition in mixed forests. Full article

Daknamu (Broussonetia × kazinoki), the primary fiber source for hanji (traditional Korean handmade paper), provides fibers that are highly durable and used in fine-edition publishing as well as in the conservation and restoration of cultural heritage materials and historic books. However, hanji production has declined due to decreased farm cultivation of B. × kazinoki, emphasizing the need for efficient vegetative propagation. This study evaluated the effects of three rooting media (commercial substrate, a mixture of commercial substrate and decomposed granite soil, and decomposed granite soil) and two plant growth regulators (auxins), 1-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA), including a rooting powder containing 0.8% IBA, on rooting performance and physiological responses. Decomposed granite soil produced the highest rooting rate, and the rooting effect index peaked with the rooting powder treatment. Exogenous auxins consistently increased the rooting rate and improved root traits. Photosynthetic activity was enhanced in decomposed granite soil, indicating improved water uptake following root development. Chlorophyll fluorescence showed a low F_v/F_m ratio and a JIP pattern indicative of stress. Soil analyses confirmed greater aeration and drainage in decomposed granite soil but revealed limitations in post-rooting water and nutrient availability. Root traits were positively correlated with photosynthetic parameters and available phosphorus, whereas electrical conductivity, cation-exchange capacity, moisture, organic matter, total nitrogen, and exchangeable cations were negatively correlated. Decomposed granite soil combined with 1500 mg·L⁻¹ IBA or rooting powder provided practical conditions for nursery-scale propagation. These findings provide a scientific basis for developing efficient cutting propagation systems for B. × kazinoki in farms and nurseries. Full article

In the semi-arid Loess Plateau of China, afforestation frequently leads to soil water depletion, threatening ecosystem sustainability. Although mixed-species plantations are encouraged to enhance resource use efficiency, their effects on deep soil water and root distribution strategies remain unclear. This study compared soil water content (SWC), deep soil water deficit (SWD), and fine root distribution in pure and mixed plantations of Robinia pseudoacacia, Platycladus orientalis, and Hippophae rhamnoides to assess whether species mixing intensifies consumption for deep soil water. Soil moisture and root samples were collected with a maximum depth of 20 m across five stand types in August 2018 and during the 2019 growing season. Results showed that mixed stands exhibited shallower water depletion depth and lower SWC below 2 m than pure stands, but a more severe deep soil water deficit, with observed SWD exceeding the expected values by 12% in the R. pseudoacacia-P. orientalis mixture (MRP) and 22% in the H. rhamnoides-P. orientalis mixture (MHP), indicating intensified water consumption below 2 m. In the MRP, the maximum rooting depth was shallower than in the corresponding pure stands. Within the mixture, species-specific root plasticity was observed: the normalized fine root length density (FRLD) of P. orientalis was four times greater in mixture than in pure stand, whereas that of R. pseudoacacia was 62% lower, suggesting divergent foraging strategies. Correlation analyses indicated that SWC was differently associated with root traits between pure and mixed stands, with relationships varying by soil depth. Mixed-effects models confirmed that both plantation type and soil depth significantly influenced FRLD and Root dry weight density (RDWD), while specific root length (SRL) was mainly affected by plantation type and its interaction with depth. These findings demonstrated that mixed-species afforestation intensifies deep soil water competition. Therefore, sustainable management should prioritize the selection of species with complementary root foraging strategies and the optimization of planting densities in semi-arid regions. Full article

Understanding belowground carbon dynamics is essential for predicting the carbon balance of forest ecosystems. This study aimed to investigate links between soil CO₂ efflux (R_S), soil physicochemical properties, and fine-root morphology across four middle-aged plantations of different species (Robinia pseudoacacia, Quercus mongolica, Pinus koraiensis, and Metasequoia glyptostroboides) in Mt. Ansan, Seoul, Republic of Korea. Seasonal measurements of R_S, soil temperature (T_S), and soil water content (SWC) were conducted, and soils and fine roots (≤2.0 mm) were analyzed for physicochemical properties and morphological traits, with a focus on very-fine roots (≤0.5 mm). The results showed that R_S was positively correlated with T_S (r = 0.77) and negatively with SWC (r = −0.33). R_S normalized at 25 °C (R₂₅), differed significantly among plantations, and exhibited strong positive correlations with electrical conductivity (r = 0.81), as well as with total nitrogen and carbon concentrations and clay content. Among fine root traits, the length, surface area, and volume of very-fine roots exhibited the strongest associations with R₂₅, underscoring their pivotal role in regulating belowground respiration. These findings suggest that species-specific fine root strategies and soil conditions jointly control R_S dynamics, particularly under warmer conditions, and highlight very-fine root traits as key indicators of soil carbon flux in forest ecosystems. Full article

The water-level fluctuation zone (WLFZ) of the Three Gorges Reservoir (TGR) experiences seasonal submergence and exposure, resulting in soil structure degradation and intensified erosion. This study investigated how flooding duration affects root development and the erosion resistance of root–soil complexes in the WLFZ of the TGR. Two representative herbaceous species were chosen for this study: Xanthium sibiricum, an annual with a taproot system, and Cynodon dactylon, a perennial with a fibrous root system. Root traits, soil erodibility K-value, shear strength, and soil texture were measured from plant and soil samples collected at different flooding durations (145–175 m elevations). Our results showed that prolonged flooding significantly suppressed root growth, particularly in the 145–155 m zone, where root length density and root tips were markedly reduced (p < 0.05). Soil erodibility increased with flooding duration, with erodibility K-values ranging from 0.050 ± 0.002 to 0.062 ± 0.001 t·hm²·h/(MJ·mm·hm²), while shear strength declined correspondingly. Textural shifts from silty loam to silt were observed at zones experiencing extended flooding, contributing to aggregate instability and decreased internal friction angles. Notably, Cynodon dactylon demonstrated superior soil reinforcement capacity compared to Xanthium sibiricum, with its root volume and surface area significantly correlated with reduced K-values (p < 0.01) and enhanced shear strength (p < 0.001), enabling it to better prevent bank erosion under flooding conditions. These findings underscore the importance of root morphological traits in maintaining soil stability under hydrological stress and highlight the potential of perennial fibrous-rooted species for vegetation-based erosion control in fine-textured riparian zones. This study provides a theoretical basis and practical reference for ecological restoration in the WLFZ of the TGR and similar environments. Full article

Leaf nutrient resorption efficiency (NuRE) is critical for plant nutrient conservation, yet its relationship with leaf and root economic traits remains poorly understood in mangroves. We quantified nitrogen (N) and phosphorus (P) resorption across ten mangrove species (five trees and five shrubs) in Hainan, China, and related NuRE to key leaf (leaf mass per area, LMA; leaf dry mass content, LDMC; and green leaf nitrogen and phosphorus contents, N_gr and P_gr, respectively) and root (specific root length, SRL; root tissue density, RTD; root diameter, RD; and root nitrogen content, N_root) traits. We found that species with a lower leaf structural investment (LMA = 103–173 g m⁻², LDMC = 19–27%) presented a 6–45% greater N and P resorption efficiency than those with a higher structural investment (LMA = 213–219 g m⁻², LDMC = 26–31%). Contrary to global meta-analyses, higher green leaf N and P contents also predicted a greater NuRE, implying enhanced internal recycling under chronic nutrient limitation. Root traits (SRL, RTD, RD, and N_root) had no significant influence on NuRE, indicating decoupled above- versus belowground strategies. Trees and shrubs diverged in size but converged in NuRE–leaf trait relationships. These findings refine plant economics theory and guide restoration by prioritizing species with acquisitive, high-NuRE foliage for nutrient-poor coasts. Full article

Plant functional traits serve as vital tools for understanding vegetation adaptation mechanisms in changing environments. As the primary organs for nutrient acquisition from soil, fine roots are highly sensitive to environmental variations. However, current research on fine-root adaptation strategies predominantly focuses on tropical, subtropical, and temperate forests, leaving a significant gap in comprehensive knowledge regarding fine-root responses in rocky-desertification habitats. This study investigates the fine roots of Pseudotsuga sinensis across varying degrees of rocky desertification (mild, moderate, severe, and extremely severe). By analyzing fine-root morphological and nutrient traits, we aim to elucidate the trait differences and correlations under different desertification intensities. The results indicate that root dry matter content increases significantly with escalating desertification severity. Fine roots in mild and extremely severe desertification exhibit notably higher root C, K, and Mg concentrations compared to those in moderate and severe desertification, while root Ca concentration shows an inverse trend. Our correlation analyses reveal a highly significant positive relationship between specific root length and specific root area, whereas root dry matter content demonstrates a significant negative correlation with elemental concentrations. The principal component analysis (PCA) further indicates that the trait associations adopted by the forest in mild- and extremely severe-desertification environments are different from those in moderate- and severe-desertification environments. This study did not account for soil nutrient dynamics, microbial diversity, or enzymatic activity—key factors influencing fine-root adaptation. Future research should integrate root traits with soil properties to holistically assess resource strategies in rocky-desertification ecosystems. This study can serve as a theoretical reference for research on root characteristics and adaptation strategies of plants in rocky-desertification habitats. Full article