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Plant taxa and traits do not necessarily show synchronous responses to ecological disturbance. Based on the observation that taxonomically over‐diversified communities might be phenotypically redundant, we speculated that taxonomic and phenotypic community reassembly might be decoupled after fire in Mediterranean ecosystems.We applied a multi‐trait approach to describe plant community re‐assembly after fire across three 20‐year chronosequences based on 117 species and 23 traits, including whole‐plant, above‐ground and below‐ground traits. We quantified the post‐fire trajectories of different plant traits by analysing their community‐weighted means individually. We estimated the short‐ and long‐term phenotypic diversity of burned plots based on sets of traits. We also tested if trait and species turnover are decoupled across post‐fire trajectories. Finally, we calculated phenotypic redundancy, and assessed if above‐ and below‐ground traits have contrasted responses during post‐fire community reassembly.Individually, 16 out of 23 traits were affected by fire in the short term. Plant phenotypic diversity (stdMPD) decreased immediately after fire, driven by changes in whole‐ and above‐ground traits. Both whole‐ and above‐ground stdMPD in burned plots described positive trajectories across the chronosequences tending to converge with long‐unburned plots, whereas below‐ground stdMPD remained unaltered through time.Taxonomic and phenotypic beta diversity showed decoupled trajectories due to a larger species than trait replacement across time since fire. Finally, overall phenotypic redundancy of the studied plant communities described a regressive trajectory, similarly to above‐ground traits, whereas root traits kept a steady phenotypic redundancy through time.Synthesis. We provide evidence that above‐ and below‐ground traits describe different recovery trajectories after fire, with significant effects on the phenotypic redundancy of plant communities. Our results encourage the use of multi‐trait approaches to understand how the plant reassembly operates after disturbance, in order to refine ecological theory. This strategy might improve the efficacy of restoration programs through a functional approach to species selection. [ABSTRACT FROM AUTHOR]

Modern agriculture's goal of improving crop resource acquisition efficiency relies on the intricate relationship between the root system and the soil. Root and rhizosphere traits play a critical role in the efficient use of nutrients and water, especially under dynamic environments. This review emphasizes a holistic perspective, challenging the conventional separation of nutrient and water uptake processes and the necessity for an integrated approach. Anticipating climate change-induced increase in the likelihood of extreme weather events that result in fluctuations in soil moisture and nutrient availability, the study explores the adaptive potential of root and rhizosphere traits to mitigate stress. We emphasize the significance of root and rhizosphere characteristics that enable crops to rapidly respond to varying resource availabilities (i.e. the presence of water and mobile nutrients in the root zone) and their accessibility (i.e. the possibility to transport resources to the root surface). These traits encompass for example root hairs, mucilage and extracellular polymeric substance (EPS) exudation, rhizosheath formation and the expression of nutrient and water transporters. Moreover, we recognize the challenge of balancing carbon investments, especially under stress, where optimized traits must consider carbon-efficient strategies. To advance our understanding, the review calls for well-designed field experiments, recognizing the limitations of controlled environments. Non-destructive methods such as mini rhizotron assessments and in-situ stable isotope techniques, in combination with destructive approaches such as root exudation analysis, are proposed for assessing root and rhizosphere traits. The integration of modeling, experimentation, and plant breeding is essential for developing resilient crop genotypes capable of adapting to evolving resource limitation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of South China Agricultural University is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Main conclusion: Soil acidity in Ethiopian highlands impacts barley production, affecting root system architecture. Study on 300 accessions showed significant trait variability, with potential for breeding enhancement. Soil acidity poses a significant challenge to crop production in the highland regions of Ethiopia, particularly impacting barley, a crucial staple crop. This acidity serves as a key stressor affecting the root system architecture (RSA) of this crop. Hence, the objective of this study was to assess the RSA traits variability under acidic soil conditions using 300 barley accessions in a greenhouse experiment. The analysis of variance indicated substantial variations among the accessions across all traits studied. The phenotypic coefficient of variation ranged from 24.4% for shoot dry weight to 11.1% for root length, while the genotypic coefficient variation varied between 18.83 and 9.2% for shoot dry weight and root length, respectively. The broad-sense heritability ranged from 36.7% for leaf area to 69.9% for root length, highlighting considerable heritability among multiple traits. The genetic advances as a percent of the mean ranged from 13.63 to 29.9%, suggesting potential for enhancement of these traits through breeding efforts. Principal component analysis and cluster analysis grouped the genotypes into two major clusters, each containing varying numbers of genotypes with contrasting traits. This diverse group presents an opportunity to access a wide range of potential parent candidates to enhance genetic variablity in breeding programs. The Pearson correlation analysis revealed significant negative associations between root angle (RA) and other RSA traits. This helps indirect selection of accessions for further improvement in soil acidity. In conclusion, this study offers valuable insights into the RSA characteristics of barley in acidic soil conditions, aiding in the development of breeding strategies to enhance crop productivity in acidic soil environments. [ABSTRACT FROM AUTHOR]

This study assessed the influence of exogenous ME in the mitigation of cold damage in pepper seedlings. Melatonin (ME) is a dynamic molecule that helps plants cope with stress in several ways. Cold stress (CS) is one of the most important environmental factors that restrict plant growth and yield. Pepper (Capsicum annuum L.) is a valuable commercial crop, highly sensitive to CS. Thus, identifying an efficient strategy to mitigate cold damage is critical for long-term pepper production. For this purpose, the roots of pepper seedlings were pretreated with ME (5 μmol · L−1) and exposed to CS for 7 d. The results indicated that CS suppressed pepper growth, hampered photosynthetic capacity, and damaged root architecture in pepper plants. In contrast, the production of reactive oxygen species (ROS), malondialdehyde (MDA), electrolyte leakage (EL), proline, and soluble sugars were enhanced in plants under CS. ME (5 μmol · L−1) pretreatment reduced the negative effects of CS by recovering plant growth, root traits, gas exchange elements, and pigment molecules compared to CS control treatment. Furthermore, ME application efficiently reduced oxidative stress markers [hydrogen peroxide (H2O2), superoxide ion (O2·–), EL, and MDA] while increasing proline and soluble sugar content in pepper leaves. ME application combined with CS further increased antioxidant enzymes and related gene expression. Collectively, our results confirmed the mitigating potential of ME supplementation for CS by maintaining pepper seedling growth, improving the photosynthesis apparatus, regulating pigments, and osmolyte content.

Plant roots employ diverse strategies to acquire soil nutrients, including direct nutrient uptake through absorptive fine roots and root hairs, scavenging nutrients by forming symbioses with mycorrhizal fungi, and mining nutrients by releasing root exudates. However, whether these three strategies are differently coordinated among phylogenetically closely related tree species and how this coordination shifts with stand development remains largely unclear.To fill these knowledge gaps, we measured 13 root morphological, architectural, physiological and mycorrhizal traits tightly related to nutrient‐acquisition of three Pinus species (P. sylvestris var. mongolica, P. densiflora and P. tabuliformis) at young (20‐year‐old) and mature (50‐year‐old) stages planted in nutrient‐impoverished sandy soils, in Northeast China.We found that young trees had thinner absorptive fine roots and a higher specific root length than mature trees across three Pinus species, indicating that roots become morphologically less efficient in 'do it yourself' scavenging nutrients during stand development. Moreover, young stands had greater root length density and root area index, and mature stands had faster root‐exudation rates, suggesting that young stands rely more on expanding soil volumes to scavenge nutrients and mature stands depend more on root exudation to 'mine' nutrients. The three Pinus species exhibited different nutrient‐acquisition strategies at the mature stage; P. densiflora had higher root length density and root area index, and the other two Pinus species had greater ectomycorrhizal colonization rates.Synthesis. Our findings highlight that phylogenetically closely related tree species may exhibit different nutrient‐acquisition strategies and suggest a shift from an extensive nutrient‐acquisition mode depending more on absorptive fine roots to an intensive nutrient‐acquisition mode relying more on root exudation during stand development. [ABSTRACT FROM AUTHOR]

This study assessed the influence of exogenous ME in the mitigation of cold damage in pepper seedlings. Melatonin (ME) is a dynamic molecule that helps plants cope with stress in several ways. Cold stress (CS) is one of the most important environmental factors that restrict plant growth and yield. Pepper (Capsicum annuum L.) is a valuable commercial crop, highly sensitive to CS. Thus, identifying an efficient strategy to mitigate cold damage is critical for long-term pepper production. For this purpose, the roots of pepper seedlings were pretreated with ME (5 mmol $ L-1) and exposed to CS for 7 d. The results indicated that CS suppressed pepper growth, hampered photosynthetic capacity, and damaged root architecture in pepper plants. In contrast, the production of reactive oxygen species (ROS), malondialdehyde (MDA), electrolyte leakage (EL), proline, and soluble sugars were enhanced in plants under CS. ME (5 mmol $ L-1) pretreatment reduced the negative effects of CS by recovering plant growth, root traits, gas exchange elements, and pigment molecules compared to CS control treatment. Furthermore, ME application efficiently reduced oxidative stress markers [hydrogen peroxide (H2O2), superoxide ion (O2 $e), EL, and MDA] while increasing proline and soluble sugar content in pepper leaves. ME application combined with CS further increased antioxidant enzymes and related gene expression. Collectively, our results confirmed the mitigating potential of ME supplementation for CS by maintaining pepper seedling growth, improving the photosynthesis apparatus, regulating pigments, and osmolyte content. [ABSTRACT FROM AUTHOR]

Modern agriculture’s goal of improving crop resource acquisition efficiency relies on the intricate relationship between the root system and the soil. Root and rhizosphere traits play a critical role in the efficient use of nutrients and water, especially under dynamic environments. This review emphasizes a holistic perspective, challenging the conventional separation of nutrient and water uptake processes and the necessity for an integrated approach. Anticipating climate change-induced increase in the likelihood of extreme weather events that result in fluctuations in soil moisture and nutrient availability, the study explores the adaptive potential of root and rhizosphere traits to mitigate stress. We emphasize the significance of root and rhizosphere characteristics that enable crops to rapidly respond to varying resource availabilities (i.e. the presence of water and mobile nutrients in the root zone) and their accessibility (i.e. the possibility to transport resources to the root surface). These traits encompass for example root hairs, mucilage and extracellular polymeric substance (EPS) exudation, rhizosheath formation and the expression of nutrient and water transporters. Moreover, we recognize the challenge of balancing carbon investments, especially under stress, where optimized traits must consider carbon-efficient strategies. To advance our understanding, the review calls for well-designed field experiments, recognizing the limitations of controlled environments. Non-destructive methods such as mini rhizotron assessments and in-situ stable isotope techniques, in combination with destructive approaches such as root exudation analysis, are proposed for assessing root and rhizosphere traits. The integration of modeling, experimentation, and plant breeding is essential for developing resilient crop genotypes capable of adapting to evolving resource limitation.

Through a variety of mechanisms, including increasing the amount of readily available mineral nutrients, regulating phytohormone levels, and biocontrol of phytopathogens, plant growth-promoting rhizobacteria (PGPR) associated with the plant rhizosphere either directly or indirectly stimulates plant growth and development. The establishment, survival, and persistence of PGPR inoculants are widely acknowledged to be contingent upon these two parameters, in addition to the intricate network of interactions within the rhizosphere. In general, the soil is a moist environment with significant amounts of carbon that have been degraded and harbors a large population of soil microbes. The rhizo-microbiome is crucial to agriculture because a wide variety of root exudates and plant cell debris attract unique and distinct patterns of microbial colonization. The rhizo-microbiome plays a crucial role in the manufacture and regulation of extracellular molecules, including hormones, secondary metabolites, antibiotics, and various signaling chemicals. Additionally, the microbial composition within the rhizo-microbiome influences soil texture enhancement. Research has shown that PGPR can be used to treat plants or inoculate plants to promote plant development. PGPR alters the physiology of the entire plant, which enhances nutrient uptake and affects the effectiveness of root activity. The specific biochemical processes of plants involved in this phenomenon are often not well understood. Nevertheless, new studies have shed light on the mechanisms via which signaling by PGPR can induce various plant responses, both at the local and systemic levels. Insufficient information is available regarding the impact of the PGPR mechanism and molecules on metabolic pathways in root characteristics. Consequently, this review will concentrate on elucidating the PGPR mechanism and identifying the essential molecules that exert influence on root-microbe interactions.

Climate change and human development will lead to an increase in groundwater levels. This will have a particularly severe impact on arid ecosystems that are highly dependent on groundwater, as overconsumption and pollution of water resources can lead to faster depletion of groundwater. This not only exacerbates the problem of groundwater scarcity, but also may have profound impacts on local ecological environment and biodiversity. However, previous research has focused on aboveground trait responses to precipitation deficits, with less emphasis on concomitant belowground impacts and deep soil drought from groundwater depletion. Therefore, it remains unclear how groundwater depletion affects above and belowground traits of plant to jointly regulate aboveground biomass. In this study, we assessed morphological and ecophysiological traits of two dominant species (herb: Pennisetum centrasiaticum and shrub: Artemisia halodendron) across three groundwater depth (50 cm, 100 cm, and 200 cm) in the Horqin Sandy Land in China, within which photosynthetic rate (Photo), stomatal conductance (Cond), transpiration rate (Tr), internal CO2 concentration (Ci), instantaneous water-use efficiency of leaves (Lwue), total nitrogen (LN) and phosphorus (LP) content of the leaves, root to shoot ratio (RSR), root length density (RLD), total root length (RTL), root length ratio (RLR) were measured. The result showed that the two species growing with increased groundwater depth had reduced photosynthetic rate, and regulated stomatal close to aggregate ability of instantaneous water use efficiency, which may allow plants to meet resource demands under drought stress avoiding transpiration water loss. Plants also reduced the density of all roots and adjusted the vertical distribution of coarse root by changing biomass distribution to acquire deeper soil available water. Correlation analysis showed that the vital traits for aboveground biomass responses appear to be groundwater depth, soil moisture, leaf area, photosynthesis, water use efficiency, and root traits. Overall, the biomass production response of two dominant species may be greatly influenced by the interaction between aboveground and belowground traits in response to changes in groundwater depth. This result contributes to our understanding of adaptive strategies of vegetation in sandy soils and provides additional support for enhancing vegetation productivity in semi-arid ecosystems. The ability of semi-arid ecosystems to predict vegetation dynamics under current and future increasing groundwater depths is crucial.

Salt spray is a major environmental issue in coastal areas. Cinnamomum camphora is an economically important tree species that grows in the coastal areas of southern China. Arbuscular mycorrhizal fungi (AMF) can alleviate the detrimental effects of abiotic stress on host plants. However, the mechanism by which AMF mitigates the adverse effects of salt spray on C. camphora remains unclear. A pot experiment was conducted in a greenhouse, where C. camphora seedlings were exposed to four AMF regimes (inoculation with sterilized fungi, with Glomus tortuosum, Funneliformis mosseae, either alone or in combination) and three salt spray regimes (applied with distilled water, 7, and 14 mg NaCl cm−2) in order to investigate the influence on root functional traits and plant growth. The results showed that higher salt spray significantly decreased the K+ uptake, K+/Na+ ratio, N/P ratio, total dry weight, and salinity tolerance of non-mycorrhizal plants by 37.9%, 71%, 27.4%, 12.7%, and 221.3%, respectively, when compared with control plants grown under non-salinity conditions. Mycorrhizal inoculation, particularly with a combination of G. tortuosum and F. mosseae, greatly improved the P uptake, total dry weight, and salinity tolerance of plants grown under higher salt spray conditions by 51.0%, 36.7%, and 130.9%, respectively, when compared with their counterparts. The results show that AMF can alleviate the detrimental effects of salt spray on C. camphora seedlings. Moreover, an enhanced uptake of K+ and P accounted for the resistance of the plants to salt spray. Therefore, pre-inoculation with a combination of G. tortuosum and F. mosseae to improve nutrient acquisition is a potential method of protecting C. camphora plants against salt spray stress in coastal areas. [ABSTRACT FROM AUTHOR]

Simple Summary: Barnyard grass (Echinochloa spp.) is one of the most dominant and noxious weed species in rice paddies. However, allelopathic rice is known to interfere with the growth of barnyard grass through allelochemical-mediated root interactions. Here, the allelopathic rice cultivar, "PI312777" (PI), and the non-allelopathic rice cultivar, "Lemont" (LE), were used as the materials for analysis and were subjected to the stresses of quinclorac-resistant (R) and -susceptible (S) barnyard grass, respectively. We first investigated changes in the morphological traits of the roots of two rice cultivars. Meanwhile, the levels of different plant hormones, including auxin, abscisic acid, jasmonic acid, and salicylic acid, known for their diverse adaptation strategies to biotic stress, were analyzed. The results indicated that PI demonstrated the greater competitive ability, compared to LE, under barnyard grass-induced stress, with respect to shoot and root biomass, the number of root tips, and root tip length in rice with root diameters of <0.5 mm. Salicylic acid (SA) and jasmonic acid (JA) were found to have the potential to suppress barnyard grass growth in allelopathic rice. The amounts of SA and JA demonstrated a significant correlation with the number of root tips and root tip length in rice with root diameters of <0.5 mm. Our research may aid in the development of strategies for reducing the environmental impact of herbicides through the prudent selection of non-chemical control tactics. Despite the growing knowledge concerning allelopathic interference with barnyard grass, little is understood regarding the competitive physiological mechanisms of the interaction between allelopathic rice and herbicide-resistant barnyard grass. A hydroponic system was employed to investigate the root morphological traits and different phytohormonal changes in allelopathic and non-allelopathic rice cultivars when co-planted with quinclorac-resistant and -susceptible barnyard grass, respectively. The results show that shoot and root biomass were greater in PI. Barnyard grass stress induced an increase in shoot and root biomass in PI at 7 and 14 days of co-culturing rice and barnyard grass. Especially under the stress of quinclorac-resistant barnyard grass, the shoot biomass of PI increased by 23% and 68%, respectively, and the root biomass increased by 37% and 34%, respectively. In terms of root morphology, PI exhibited a significantly higher fine-root length, in root diameters of <0.5 mm, a greater number of root tips, and longer root tips compared to LE. The response to quinclorac-resistant barnyard grass stress was consistent in terms of the SA and JA content. The obvious accumulation of SA and JA was observed in two rice cultivars under quinclorac-resistant barnyard grass stress, with greater amounts of SA and JA in PI. The significant decrease in auxin (IAA) and abscisic acid (ABA) content in rice was detected from 7 to 14 days under co-culture stress. Additionally, highly significant and positive correlations were found between SA and JA content, and the number of root tips and root tip length at root diameters of 0–0.5 mm in rice. [ABSTRACT FROM AUTHOR]

Aims: Interactions among plant species play an essential role in the establishment and performance of intercropped forest plantations and depend on the characteristics of the intercropped species and environmental conditions. Although much is known about interspecific interactions, how light conditions modulate these interactions remains unknown. Methods: In this study, we explored the effects of light intensity (shade or full light) on plant-plant interactions through a controlled pot experiment involving two local companion tree species (Phoebe chekiangensis and Torreya grandis) and Phyllostachys edulis in different planting patterns (monoculture or intercropping). Results: The effect of interspecific interaction on plant performance depended on light intensity and species. Under full light, heterogeneous neighboring plants tended to increase the nitrogen concentration in shoots and roots of the three species, while the total biomass and root-shoot mass ratio also increased for P. edulis and P. chekiangensis. Under shade conditions, all monocultures adapted to low light through a series of changes (increase in specific leaf area and chlorophyll concentration, or decrease of root-shoot ratios), while these adaptive strategies were limited in P. chekiangensis and T. grandis intercropped with P. edulis. And the performance of T. grandis was less influenced by P. edulis than by P. chekiangensis due to differences in root attributes. Conclusion: Under shade condition, P. edulis may inhibit the nitrogen acquisition of the two companion species through the plasticity advantage of root morphology and physiology traits, thus limiting their aboveground adaptive capacity to low light. [ABSTRACT FROM AUTHOR]

Plant invasion has severely damaged ecosystem stability and species diversity worldwide. The cooperation between arbuscular mycorrhizal fungi (AMF) and plant roots is often affected by changes in the external environment. Exogenous phosphorus (P) addition can alter the root absorption of soil resources, thus regulating the root growth and development of exotic and native plants. However, it remains unclear how exogenous P addition regulates the root growth and development of exotic and native plants mediated by AMF, affecting the exotic plant invasion. In this experiment, the invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum were selected and cultured under intraspecific (Intra-) competition and interspecific (Inter-) competition conditions, involving inoculation with (M+) and without AMF (M−) and three different levels of P addition including no addition (P0), addition with 15 mg P kg−1 soil (P15), and addition with 25 mg P kg−1 soil (P25) for the two species. Root traits of the two species were analyzed to study the response of the two species' roots to AMF inoculation and P addition. The results showed that AMF significantly promoted the root biomass, length, surface area, volume, tips, branching points, and carbon (C), nitrogen (N), and P accumulation of the two species. Under M+ treatment, the Inter- competition decreased the root growth and nutrient accumulation of invasive E. adenophorum but increased the root growth and nutrient accumulation of native E. lindleyanum relative to the Intra- competition. Meanwhile, the exotic and native plants responded differently to P addition, exhibiting root growth and nutrient accumulation of invasive E. adenophorum increased with P addition, whereas native E. lindleyanum reduced with P addition. Further, the root growth and nutrition accumulation of native E. lindleyanum were higher than invasive E. adenophorum under Inter- competition. In conclusion, exogenous P addition promoted the invasive plant but reduced the native plant in root growth and nutrient accumulation regulated by AMF, although the native plant outcompeted the invasive plant when the two species competed. The findings provide a critical perspective that the anthropogenic P fertilizer addition might potentially contribute to the successful invasion of exotic plants. [ABSTRACT FROM AUTHOR]

Summary: A key trait conferring flood tolerance is the ability to grow adventitious roots as a response to submergence. The genetic traits of deepwater rice determining the development and characteristics of aquatic adventitious roots (AAR) had not been evaluated.We used near‐isogenic lines introgressed to test the hypothesis that the impressive shoot elongation ability of deepwater rice linked to quantitative trait loci 1 and 12 also promote the development of AAR.The deepwater rice genotype NIL‐12 possessed expanded regions at the stem nodes where numerous AAR developed as a response to submergence. Two types (AR1 and AR2) of roots with distinct timing of emergence and large differences in morphological and anatomical traits formed within 3 (AR1) to 7 (AR2) d of submergence. The mechanical impedance provided by the leaf sheath caused AR2 to emerge later promoting thicker roots, higher elongation capacity and higher desiccation tolerance. Upregulation of key genes suggests a joint contribution in activating the meristem in AAR enhancing the development of these in response to submergence.The morphological and anatomical traits suggested that AR2 is better adapted to long‐term flooding than AR1. We therefore propose that AR2 in deepwater rice functions as an evolutionary defence strategy to tackle periodic submergence. See also the Commentary on this article by Maric & Hartman, 238: 1337–1339. [ABSTRACT FROM AUTHOR]

Root system architecture is important for common bean (Phaseolus vulgaris) adaptability to diverse environments. Beans employ complex adaptive root mechanisms for coping with multiple stresses in production environments. Understanding genetic control of root traits is central to improvement of common bean for adaptation to marginal environments. The objectives of this study were to (i) determine combining ability of root and agronomic traits and (ii) estimate the heritability and genetic correlation of root and agronomic traits in common bean. Four bean lines with superior root traits were crossed with four locally adapted varieties in a North Carolina II mating scheme to generate 16 crosses. The 16 F1s were selfed and advanced to F2 generation. Eight parents and their F2 progenies were evaluated in an alpha‐Lattice design with two replications. General and specific combing ability mean squares were significant (p ≤.05) for all traits measured. General predictability ratios ranged from.47 to.68 across locations suggesting that both additive and non‐additive gene action modulate root traits and seed yield. Positive and significant (p ≤.05) phenotypic and genetic correlations revealed significant association between root traits and yield. Moderate to high heritability estimates of between.43 and.67 were realized. Such estimates point to possible deployment of a successful selection programme. Genotype AFR398 displayed significant positive GCA effects among its crosses for both root and agronomic traits hence a potential candidate genotype for inclusion in a bean genetic improvement programme for marginal environments. [ABSTRACT FROM AUTHOR]

Soybean [Glycine max (L.) Merr.], an important oilseed crop, is a low-cost source of protein and oil. In Southeast Asia and Africa, soybeans are widely cultivated for use as traditional food and feed and industrial purposes. Given the ongoing changes in global climate, developing crops that are resistant to climatic extremes and produce viable yields under predicted climatic conditions will be essential in the coming decades. To develop such crops, it will be necessary to gain a thorough understanding of the genetic basis of agronomic and plant root traits. As plant roots generally lie beneath the soil surface, detailed observations and phenotyping throughout plant development present several challenges, and thus the associated traits have tended to be ignored in genomics studies. In this study, we phenotyped 357 soybean landraces at the early vegetative (V2) growth stages and used a 180 K single-nucleotide polymorphism (SNP) soybean array in a genome-wide association study (GWAS) conducted to determine the phenotypic relationships among root traits, elucidate the genetic bases, and identify significant SNPs associated with root trait-controlling genomic regions/loci. A total of 112 significant SNP loci/regions were detected for seven root traits, and we identified 55 putative candidate genes considered to be the most promising. Our findings in this study indicate that a combined approach based on SNP array and GWAS analyses can be applied to unravel the genetic basis of complex root traits in soybean, and may provide an alternative high-resolution marker strategy to traditional bi-parental mapping. In addition, the identified SNPs, candidate genes, and diverse variations in the root traits of soybean landraces will serve as a valuable basis for further application in genetic studies and the breeding of climate-resilient soybeans characterized by improved root traits. [ABSTRACT FROM AUTHOR]

It is well known that roots play a significant role in reducing water erosion in soil, yet few studies have reported the influence of crop roots on soil translocation induced by tillage in sloping fields. To examine the relationship between soil-root complexes (i.e., complexes of wheat roots and soil) and soil redistribution caused by tillage, a series of tillage experiments were carried out on bare soil and areas of wheat sown by drilling (DS) and nesting (NS) using nine slopes with gradients varying from 0.19 to 0.32 m m−1. The magnetic tracing technique was used to determine soil translocation rates under hoeing tillage in sloping landscapes in response to soil-root complexes and bare soil. The results indicated that mean displacement distance for DS and NS in the downslope direction was 0.15 m and 0.16 m, respectively. This was much shorter than that of bare soil which was 0.26 m. Mean tillage erosion rates ranged from 14.58 to 19.15 Mg ha−1 per tillage pass for DS and 13.90 –21.10 Mg ha−1 per tillage pass for NS , while reached 31.23–36.31 Mg ha−1 per tillage pass for bare soil. Tillage transport coefficients (k 3 and k 4) were 6.31 and 106.46 kg m−1 per tillage pass for DS , 6.58 and 118.68 kg m−1 per tillage pass for NS , and 28.12 and 151.07 kg m−1 per tillage pass for bare soil, respectively. A significant difference in cohesive force (C) was found between DS (NS) and bare soil (P < 0.05), thereby resulting in an increase in the soil shear strength of soil-root complexes. Compared with those of bare soil, the soil fractal dimension of soil-root complexes decreased significantly due to an increase in the percentage of coarse clods (>100 and 100–80 mm) and a decrease in the percentage of fine clods (50–20 and < 20 mm). Mean soil displacement distance caused by tillage displayed a negative relationship with C and wheat root traits (the root density, the root length density, and the root area ratio) within the hilly landscape of soil-root complexes (P < 0.05), implying that wheat roots played a crucial part in soil translocation and soil fragmentation during hoeing tillage. Our study revealed that soil-root complexes markedly reduce the soil downslope transfer process during tillage and prevent the break-up of large clods by tillage implements on sloping farmland. • Wheat root attenuated the mechanical breakage of clods during tillage operation. • Root systems increase soil shear strength and reduce fragmentation of soil clods. • Displacement distance for soil-root complexes was smaller than that for bare soil. • Tillage erosion decreased with increasing structure stability and cohesive force. [ABSTRACT FROM AUTHOR]

Abstract Background Arbuscular mycorrhizal (AM) fungi and roots play important roles in plant nutrient acquisition, especially in nutrient poor and heterogeneous soils. However, whether an accumulation strategy of AM fungi and root exists in such soils of karst shrubland ecosystems remains unclear. Root traits related to nutrient acquisition (root biomass, AM colonisation, root acid phosphatase activity and N2 fixation) were measured in two N2-fixing plants (i.e. Albizia odoratissima (Linn. f.) Benth. and Cajanus cajan (Linn.) Millsp.) that were grown in heterogeneous or homogeneous nutrient (ammonium) soil with and without AM fungi inoculation. Results Both of these plants had higher AM colonisation, root biomass and relative growth rate (RGR), but lower N2 fixation and root acid phosphatase activity in the rhizosphere in the heterogeneous soil environment, than that in the homogeneous soil environment. Plants grown in the AM fungi-inoculated heterogeneous soil environment had increased root biomass and root acid phosphatase activity compared with those grown in soil without inoculation. AM colonisation was negatively correlated with the N2 fixation rate of A. odoratissima, while it was not significantly correlated with the root phosphatase activity. Conclusions Our results indicated that enhanced AM symbiosis and root biomass increased the absorptive surfaces for nutrient acquisition, highlighting the accumulation strategies of AM and root traits for plant nutrient acquisition in nutrient poor and heterogeneous soils of the karst shrubland ecosystem.

Salt spray is a major environmental issue in coastal areas. Cinnamomum camphora is an economically important tree species that grows in the coastal areas of southern China. Arbuscular mycorrhizal fungi (AMF) can alleviate the detrimental effects of abiotic stress on host plants. However, the mechanism by which AMF mitigates the adverse effects of salt spray on C. camphora remains unclear. A pot experiment was conducted in a greenhouse, where C. camphora seedlings were exposed to four AMF regimes (inoculation with sterilized fungi, with Glomus tortuosum, Funneliformis mosseae, either alone or in combination) and three salt spray regimes (applied with distilled water, 7, and 14 mg NaCl cm−2) in order to investigate the influence on root functional traits and plant growth. The results showed that higher salt spray significantly decreased the K+ uptake, K+/Na+ ratio, N/P ratio, total dry weight, and salinity tolerance of non-mycorrhizal plants by 37.9%, 71%, 27.4%, 12.7%, and 221.3%, respectively, when compared with control plants grown under non-salinity conditions. Mycorrhizal inoculation, particularly with a combination of G. tortuosum and F. mosseae, greatly improved the P uptake, total dry weight, and salinity tolerance of plants grown under higher salt spray conditions by 51.0%, 36.7%, and 130.9%, respectively, when compared with their counterparts. The results show that AMF can alleviate the detrimental effects of salt spray on C. camphora seedlings. Moreover, an enhanced uptake of K+ and P accounted for the resistance of the plants to salt spray. Therefore, pre-inoculation with a combination of G. tortuosum and F. mosseae to improve nutrient acquisition is a potential method of protecting C. camphora plants against salt spray stress in coastal areas.

Despite the growing knowledge concerning allelopathic interference with barnyard grass, little is understood regarding the competitive physiological mechanisms of the interaction between allelopathic rice and herbicide-resistant barnyard grass. A hydroponic system was employed to investigate the root morphological traits and different phytohormonal changes in allelopathic and non-allelopathic rice cultivars when co-planted with quinclorac-resistant and -susceptible barnyard grass, respectively. The results show that shoot and root biomass were greater in PI. Barnyard grass stress induced an increase in shoot and root biomass in PI at 7 and 14 days of co-culturing rice and barnyard grass. Especially under the stress of quinclorac-resistant barnyard grass, the shoot biomass of PI increased by 23% and 68%, respectively, and the root biomass increased by 37% and 34%, respectively. In terms of root morphology, PI exhibited a significantly higher fine-root length, in root diameters of

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Indoleacetic acid (IAA) is an important regulator that plays a crucial role in plant growth and responses to abiotic stresses. In the present study, a sand cultivation experiment was carried out to investigate the effects of IAA at different concentrations (0, 0.01, 0.1, 0.5, 1, and 2.5 mmol/L) on maize growth, root morphology, mineral elements (Ca, Mg) and Cd uptake under 20 mg/kg Cd stress. The results showed that 0.01 mmol/L is the optimal IAA concentration for enhancing the Cd tolerance of maize. Compared with the control treatment, 0.01 mmol/L IAA promoted maize growth, with significant increases in the height, shoot and root biomass by 34.6%, 25.0% and 16.3%; altered the root morphology, with increases in root length, root tip number, and root tip density by 8.9%, 31.4% and 20.7%, respectively; and enhanced the mineral element uptake of maize, resulting in significant increases in the Ca content in shoots and roots by 640.6% and 1036.4% and in the Mg content in shoots by 205.8%, respectively. In addition, 0.01 mmol/L IAA decreased the Cd content and uptake in the shoots by 51.9% and 39.6%, respectively. Furthermore, the Cd content and uptake exhibited a significant negative correlation with Ca content in roots and a significantly positive correlation with root morphology, and the Cd content in shoots was significantly and negatively correlated with root tip number. Thus, 0.01 mmol/L IAA was effective in enhancing the Cd tolerance and plant growth of maize. [ABSTRACT FROM AUTHOR]

In forest ecosystems, changes in the expression of tree absorptive root traits following management interventions are expected to influence post-thinning forest structure and function. Fine root traits are expected to be especially responsive to forest thinning-one of the most common forest management interventions and the focus of our research here-influencing tree-level responses to environmental change, and thereby contributing to post-thinning stand-level dynamics and ecosystem processes. However, there remains limited understanding surrounding whether or not forest thinning influences the expression of root morphological, chemical, and physiological traits associated with belowground resource acquisition. We conducted a global meta-analysis to evaluate the response of 13 fine root traits to forest thinning. Our study included analysis of 769 paired observations of root traits values pre- and post-thinning, derived from 89 peer-reviewed publications. Our meta-analysis found that forest thinning leads to a decrease in fine root biomass by 11.7% on average, while other root traits including fine root length, root C and N concentrations, root lifespan, and root respiration rates, are largely unresponsive to thinning treatments. Thinning tended to reduce fine root biomass at early stand recovery stages, with increases in fine root biomass being detected at later seral stages, especially in heavy thinning experiments. The effect of thinning on fine root biomass was most pronounced in deeper soil horizons. The influence of thinning on fine root trait expression was not affected by ecosystem or stand type, with the exception of biomass which decreased in temperate and coniferous forests. Our results demonstrate variations of fine root traits to forest management, as well as the importance of stand recovery time and thinning intensity in regulating fine root trait expression in retention trees. These patterns may have strong implications for governing soil carbon stocks in managed forests associated with decreased root inputs into deeper soils. Overall, our findings can enhance our comprehension of how forest management affects fine root trait expression, and relationship between managed forests and belowground ecosystem structure and function., Competing Interests: Declaration of competing interest No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication. I would like to declare on behalf of my coauthors that the work described was original research that has not been published previously, and not under consideration for publication elsewhere, in whole or in part. All the authors listed have approved the manuscript that is enclosed., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Plant invasion has severely damaged ecosystem stability and species diversity worldwide. The cooperation between arbuscular mycorrhizal fungi (AMF) and plant roots is often affected by changes in the external environment. Exogenous phosphorus (P) addition can alter the root absorption of soil resources, thus regulating the root growth and development of exotic and native plants. However, it remains unclear how exogenous P addition regulates the root growth and development of exotic and native plants mediated by AMF, affecting the exotic plant invasion. In this experiment, the invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum were selected and cultured under intraspecific (Intra-) competition and interspecific (Inter-) competition conditions, involving inoculation with (M+) and without AMF (M−) and three different levels of P addition including no addition (P0), addition with 15 mg P kg−1 soil (P15), and addition with 25 mg P kg−1 soil (P25) for the two species. Root traits of the two species were analyzed to study the response of the two species’ roots to AMF inoculation and P addition. The results showed that AMF significantly promoted the root biomass, length, surface area, volume, tips, branching points, and carbon (C), nitrogen (N), and P accumulation of the two species. Under M+ treatment, the Inter- competition decreased the root growth and nutrient accumulation of invasive E. adenophorum but increased the root growth and nutrient accumulation of native E. lindleyanum relative to the Intra- competition. Meanwhile, the exotic and native plants responded differently to P addition, exhibiting root growth and nutrient accumulation of invasive E. adenophorum increased with P addition, whereas native E. lindleyanum reduced with P addition. Further, the root growth and nutrition accumulation of native E. lindleyanum were higher than invasive E. adenophorum under Inter- competition. In conclusion, exogenous P addition promoted the invasive plant but reduced the native plant in root growth and nutrient accumulation regulated by AMF, although the native plant outcompeted the invasive plant when the two species competed. The findings provide a critical perspective that the anthropogenic P fertilizer addition might potentially contribute to the successful invasion of exotic plants.

Pyramiding of relevant drought adaptive traits on to an agronomically superior cultivar and accelerating the development of stress tolerant lines in a shortest period of time through doubled haploid technology can form as an important step in crop improvement programmes. With the aim of improving the drought adaptation in rice with sustained productivity under water-limited conditions, drought adaptive traits such as root, water use efficiency (WUE) and epicuticular wax were pyramided. Pyramiding of traits was done by crossing the trait introgressed line (TIL-14) which has root and WUE traits with epicuticular wax genotype (AC35310) and accelerating the breeding cycle through doubled haploid technology. In the present study, the developed doubled rice lines were phenotyped for pyramided traits and more specifically, the root traits both in root study structures and in pots. Accordingly, a significant variability in root traits such as root length, root volume and root weight were observed among the DH lines in both the experiments to suggest that, the DH lines are diverse for root traits. Although each of the DH lines are homozygous and homogenous within but, throws out a large variation across the DH lines. Further, the root trait was found to be stable across the seasons and growing conditions as the Spearman's correlation coefficient analysis showed a strong correlation between the experiments to suggest that the root trait is more stable and can be a useful trait in crop improvement programmes. Based on the diversity, the contrasting DH lines differing in root traits was identified and selected. Further, when the relevance of root traits was examined under phenomics facility with the imposed moisture stress, the high root type DH lines performed well over the low root type DH lines suggesting the importance of root traits under water limited conditions. [ABSTRACT FROM AUTHOR]

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings. However, there is limited knowledge regarding the effects of the establishment of furrows on growth, lodging and yield, and their relationships with root traits. In this study, field experiments were conducted during 2012 and 2013 using two super rice varieties (hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan) under three furrow establishment treatments (T1, both water and seed furrows were established by the machine; T2, only seed furrows were established by the machine; and T3, neither water nor seed furrows were established by the machine). Lodging index, lodging-related traits, grain yield, above-ground dry weight and root traits were measured. The results showed that the lodging index was significantly affected by the treatments with furrows (T1 and T2). The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment (T1) in both 2012 and 2013. Lodging resistance was strongly related to the breaking resistance. No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice. Therefore, the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance, which was related to root traits.

Background: Arbuscular mycorrhizal (AM) fungi and roots play important roles in plant nutrient acquisition, especially in nutrient poor and heterogeneous soils. However, whether an accumulation strategy of AM fungi and root exists in such soils of karst shrubland ecosystems remains unclear. Root traits related to nutrient acquisition (root biomass, AM colonisation, root acid phosphatase activity and N2 fixation) were measured in two N2-fixing plants (i.e. Albizia odoratissima (Linn. f.) Benth. and Cajanus cajan (Linn.) Millsp.) that were grown in heterogeneous or homogeneous nutrient (ammonium) soil with and without AM fungi inoculation. Results: Both of these plants had higher AM colonisation, root biomass and relative growth rate (RGR), but lower N2 fixation and root acid phosphatase activity in the rhizosphere in the heterogeneous soil environment, than that in the homogeneous soil environment. Plants grown in the AM fungi-inoculated heterogeneous soil environment had increased root biomass and root acid phosphatase activity compared with those grown in soil without inoculation. AM colonisation was negatively correlated with the N2 fixation rate of A. odoratissima, while it was not significantly correlated with the root phosphatase activity. Conclusions: Our results indicated that enhanced AM symbiosis and root biomass increased the absorptive surfaces for nutrient acquisition, highlighting the accumulation strategies of AM and root traits for plant nutrient acquisition in nutrient poor and heterogeneous soils of the karst shrubland ecosystem. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs), a cost effective technology for wastewater treatment, consist of substrates and wetland plants, which should be selected carefully to gain highest treatment efficiency. However, studies on plant growth and responses to different types of substrates are very few. This study aims to assess the effects of substrate types on growth and root morphology of Canna indica L. and nitrogen (N) removal. Twenty-four similar sized approximately 1 month old C. indica plants were selected and grown on different substrates (gravel, pumice and biochar). All plants were supplied with a standard growth medium to which 14 mg L-1 NH4+, 14 mg L-1 NO3-, 3 mg L-1 PO43- were added and pH was adjusted to 6.5. The growth solution was renewed every week. The plants were grown under greenhouse conditions for 45 d. Results showed that growth of C. indica was not significantly different among treatments but differences on root morphology were found. Plants grown on pumice had the largest root diameters while plants grown on biochar had the longest roots. In the gravel-filled treatment, C. indica showed the lowest root diameter and root length but formed more internal air space in its roots. It indicates that types of substrate can affect O2 supply and root morphological adaptation. Moreover, the porous substrate bed systems were capable of eliminating more NH4+ than gravel bed systems, with the NH4+ removal rates of 5.6–6.3 mg L-1 d-1 compared to 4.7 mg L-1 d-1, respectively. The results show that porous substrates can act as plant supporting substrates and play important roles in N adsorption. Also, they can improve oxygen supply and stimulate root growth. Thus, application of porous substrates as filter media could help to increase pollutant removal efficacy of CWs.

Non-structural carbohydrates (NSCs) facilitate plant adaptation to drought stress, characterize tree growth and survival ability, and buffer against external disturbances. Previous studies have focused on the distribution and dynamics of NSCs among different plant organs under drought conditions. However, discussion about the NSC levels of fine roots in different root branch orders is limited, especially the relationship between fine root trait variation and NSC content. The objective of the study was to shed light on the synergistic variation in fine root traits and NSC content in different root branch orders under different drought and soil substrate conditions. The 2-year-old Fraxinus mandshurica Rupr. potted seedlings were planted in three different soil substrates (humus, loam, and sandy–loam soil) and subjected to four drought intensities (CK, mild drought, moderate drought, and severe drought) for 2 months. With increasing drought intensity, the biomass of fine roots decreased significantly. Under the same drought intensity, seedlings in sandy–loam soil had higher root biomass, and the coefficient of variation of 5th-order roots (37.4, 44.5, and 53% in humus, loam, and sandy–loam soil, respectively) was higher than that of lower-order roots. All branch order roots of seedlings in humus soil had the largest specific root length (SRL) and specific root surface area (SRA), in addition to the lowest diameter. With increasing drought intensity, the SRL and average diameter (AD) of all root branch orders increased and decreased, respectively. The fine roots in humus soil had a higher soluble sugar (SS) content and lower starch (ST) content compared to the loam and sandy–loam soil. Additionally, the SS and ST contents of fine roots showed decreasing and increasing tendencies with increasing drought intensities, respectively. SS and ST explained the highest degree of the total variation in fine root traits, which were 32 and 32.1%, respectively. With increasing root order, the explanation of the variation in root traits by ST decreased (only 6.8% for 5th-order roots). The observed response in terms of morphological traits of different fine root branch orders of F. mandshurica seedlings to resource fluctuations ensures the maintenance of a low cost-benefit ratio in the root system development. [ABSTRACT FROM AUTHOR]

Summary: Mangroves are among the world's most carbon‐dense ecosystems, but have suffered extensive deforestation, prompting reforestation projects. The effects of mangrove reforestation on belowground carbon dynamics are poorly understood. In particular, we do not know how fine root production develops following mangrove reforestation, despite fine root production being a major carbon sink and an important control of mangrove soil accretion.Using minirhizotrons, we investigated fine root production and its depth variation along a chronosequence of mature Vietnamese mangroves.Our results showed that fine root production decreases strongly with stand age in the uppermost 32 cm of our soil profiles. In younger mangrove stands, fine root production declines with depth, possibly due to a vertical gradient in soil nutrient availability; while root production in the oldest stand is low at all depths and exhibits no clear vertical pattern. A major fraction of fine root production occurs deeper than 30 cm, depths that are commonly omitted from calculations of mangrove carbon budgets.Younger mangroves may accrue shallow soil organic matter faster than older mangroves. Therefore, root productivity and forest stand age should be accounted for when forecasting mangrove carbon budgets and resistance to sea‐level rise. See also the Commentary on this article by Cormier, 232: 1525–1527. [ABSTRACT FROM AUTHOR]

In order to clarify the field control efficacies of two kinds of composite biocontrol agents against tobacco black shank disease and fusarium root rot disease in tobacco fields, the incidences of tobacco black shank disease and fusarium root rot disease in tobacco fields after applying the two biocontrol agents (A. the mixture of Pseudomonas and Trichoderma viride zymotic fluids at the volume ratio of 1: 1, B. the mixture of Bacillus and Trichoderma harzianum zymotic fluids at the volume ratio of 1: 1) were investigated. The agronomic trait indexes and the contents (mass fraction) of routine chemical components in aerial parts and roots of cured tobacco leaves were measured. The results showed that the composite biocontrol agent A reduced the incidence and disease index of tobacco rhizome diseases, and its relative control efficacy reached 48.46%. Both agents A and B improved the agronomic traits of tobacco plants, increased root fresh weight, root volume and the numbers of lateral roots and fibrous roots. The contents of chemical components in tobacco leaves treated with the two biocontrol agents were appropriate and their proportions were more harmonious. [ABSTRACT FROM AUTHOR]

Soybean [Glycine max (L.) Merr.], an important oilseed crop, is a low-cost source of protein and oil. In Southeast Asia and Africa, soybeans are widely cultivated for use as traditional food and feed and industrial purposes. Given the ongoing changes in global climate, developing crops that are resistant to climatic extremes and produce viable yields under predicted climatic conditions will be essential in the coming decades. To develop such crops, it will be necessary to gain a thorough understanding of the genetic basis of agronomic and plant root traits. As plant roots generally lie beneath the soil surface, detailed observations and phenotyping throughout plant development present several challenges, and thus the associated traits have tended to be ignored in genomics studies. In this study, we phenotyped 357 soybean landraces at the early vegetative (V2) growth stages and used a 180 K single-nucleotide polymorphism (SNP) soybean array in a genome-wide association study (GWAS) conducted to determine the phenotypic relationships among root traits, elucidate the genetic bases, and identify significant SNPs associated with root trait-controlling genomic regions/loci. A total of 112 significant SNP loci/regions were detected for seven root traits, and we identified 55 putative candidate genes considered to be the most promising. Our findings in this study indicate that a combined approach based on SNP array and GWAS analyses can be applied to unravel the genetic basis of complex root traits in soybean, and may provide an alternative high-resolution marker strategy to traditional bi-parental mapping. In addition, the identified SNPs, candidate genes, and diverse variations in the root traits of soybean landraces will serve as a valuable basis for further application in genetic studies and the breeding of climate-resilient soybeans characterized by improved root traits.

Non-structural carbohydrates (NSCs) facilitate plant adaptation to drought stress, characterize tree growth and survival ability, and buffer against external disturbances. Previous studies have focused on the distribution and dynamics of NSCs among different plant organs under drought conditions. However, discussion about the NSC levels of fine roots in different root branch orders is limited, especially the relationship between fine root trait variation and NSC content. The objective of the study was to shed light on the synergistic variation in fine root traits and NSC content in different root branch orders under different drought and soil substrate conditions. The 2-year-old Fraxinus mandshurica Rupr. potted seedlings were planted in three different soil substrates (humus, loam, and sandy–loam soil) and subjected to four drought intensities (CK, mild drought, moderate drought, and severe drought) for 2 months. With increasing drought intensity, the biomass of fine roots decreased significantly. Under the same drought intensity, seedlings in sandy–loam soil had higher root biomass, and the coefficient of variation of 5th-order roots (37.4, 44.5, and 53% in humus, loam, and sandy–loam soil, respectively) was higher than that of lower-order roots. All branch order roots of seedlings in humus soil had the largest specific root length (SRL) and specific root surface area (SRA), in addition to the lowest diameter. With increasing drought intensity, the SRL and average diameter (AD) of all root branch orders increased and decreased, respectively. The fine roots in humus soil had a higher soluble sugar (SS) content and lower starch (ST) content compared to the loam and sandy–loam soil. Additionally, the SS and ST contents of fine roots showed decreasing and increasing tendencies with increasing drought intensities, respectively. SS and ST explained the highest degree of the total variation in fine root traits, which were 32 and 32.1%, respectively. With increasing root order, the explanation of the variation in root traits by ST decreased (only 6.8% for 5th-order roots). The observed response in terms of morphological traits of different fine root branch orders of F. mandshurica seedlings to resource fluctuations ensures the maintenance of a low cost-benefit ratio in the root system development.

In order to analyze the genetic basis of root traits at seedling stage, we performed QTL analysis of root morphology with 148 recombinant inbred lines derived from indica variety 9311 and japonica variety Nipponbare (NPB). In two repetitions, a total of 26 QTLs were detected for the longest root length, total root length, root surface area, root volume, and root diameter, distributed on chromosomes 1, 2, 4, 7, 9, 10, and 11 in rice. Four QTL clusters on chromosomes 2, 4, 7, and 10 were found, including a major QTL qLRL4 controlling the longest root length. To fine mapping of the major QTL, we constructed a near isogenic line NIL-qLRL4 with a segment from NPB between markers IND4-1 and IND4-4 with 9311 background. With a F2 population derived from the NIL-qLRL4 and 9311, we fine mapped the qLRL4 within ~68.23 kb region between markers IND4-1 and IND4-3, where eight candidate genes located. Fine mapping of this QTL for root length will help explore genetic mechanism of root elongation and morphogenesis in rice. [ABSTRACT FROM AUTHOR]

Keywords: root trait; community-level trait; species-level trait; ecosystem functioning; scale-matching EN root trait community-level trait species-level trait ecosystem functioning scale-matching 1 5 5 07/26/21 20210722 NES 210722 Introduction Plant roots are important organs responsible for the physical support and for the acquisition of nutrients and water from the soil, which is necessary for plant growth and reproduction. The concept of root community traits urges us to measure and identify the total spatial and temporal variation in root traits, which may enable us to better link the traits with ecosystem functioning (e.g., GPP or NUE) in the natural ecosystems at a large scale. More importantly, this new concept of root community traits can help us incorporate root traits into the investigations of ecosystem functioning at large scales, as well as to improve ecological models, particularly for productivity, nutrient acquisition, and soil carbon cycling. Through overall sampling soil block, Approach IV directly obtains the community-level root traits per unit land area, which not only has the potential to bridge the mechanistic linkages between root traits and ecosystem functioning, but also is feasible at the large scale. [Extracted from the article]

Triticum boeoticum wild wheat is a remarkable gene pool to environmental stress resistance. It is one of the most valuable species of the Triticeae tribe for improving wheat cultivars to moisture-stress. This research was carried out to assess the changes and responses of different traits of 10 accessions of Triticum boeoticum under non-stress and imposed moisture stress conditions in 2015 and 2016. Most traits were significantly affected by accession (A), water treatments (WT), and A×WT interactions. The accessions showed a high-level of genetic diversity for all traits, except peduncle weight. The accessions Tb5 and TB3 with the highest amount of economic yield per plant (EYPP) and water use efficiency (WUE), were less affected by the imposed moisture stress, while accession Tb6 with the maximum amount of water use (WU), main root length (MRL) and some phenological traits, were the most affected. The traits of WUE and main stem weight (MSTW) showed the highest and the traits of excised leaf water retention (ELWR), MRL and WU showed the lowest alignment with EYPP, respectively. The ability of producing assimilates (by increasing biological yield per plant and MSTW) and the ability of faster assimilates-remobilization into grains (by increasing harvest index and WUE), has been a neglected aspect of breeding wheat program under drought stress. In other words, the ability of a genotype to produce more assimilates and allocate it to grains (by increased BYPP and WUE, respectively) instead of belowground-traits, will result to increase EYPP. For example, the Tb6 ecotype, due to the allocation of more assimilates to underground parts, had little grain yield. While the traits of WUE, BYPP, seed number per main spike, seed weight per main spike (SWPMS) and main spike weight (MSPW) showed a positive and significant (P

Mechanical hill wet-seeded rice machine is beneficial for establishing and growing uniform rows of seedlings. However, there is limited knowledge regarding the effects of the establishment of furrows on growth, lodging and yield, and their relationships with root traits. In this study, field experiments were conducted during 2012 and 2013 using two super rice varieties (hybrid rice Peizataifeng and inbred rice Yuxiangyouzhan) under three furrow establishment treatments (T1, both water and seed furrows were established by the machine; T2, only seed furrows were established by the machine; and T3, neither water nor seed furrows were established by the machine). Lodging index, lodging-related traits, grain yield, above-ground dry weight and root traits were measured. The results showed that the lodging index was significantly affected by the treatments with furrows (T1 and T2). The strongest lodging resistance was detected in the mechanical hill wet-seeded rice with furrow treatment (T1) in both 2012 and 2013. Lodging resistance was strongly related to the breaking resistance. No significant difference was found in grain yield or dry weight of the mechanical hill wet-seeded rice. Therefore, the mechanical hill wet-seeded rice with furrow treatment increased rice lodging resistance, which was related to root traits. [ABSTRACT FROM AUTHOR]

Background and aims: Identifying root types helps understand the diversity of the morphogenetic capacities of root axes. Unfortunately, root types are generally defined arbitrarily. We used an unsupervised clustering method to define root types and examine the ontogeny of the Pinus pinaster root system. Methods: K-clustering was first used on four root traits, including three geometric architectural traits: basal cross-sectional area, root tropism, parent root tropism, and branching angle. Based on these groups, we assigned all the root axes to a root type. Results: Clustering yielded the same five groups of lateral roots and explained the same percentage of variance (70%) whatever the tree age. This way, 11,004 root axes from 69 excavated root systems ranging from 3 to 50 years were assigned in 5 types. P. pinaster root axes showed large differences based on root tropism and parent root tropism intensity. The larger horizontal shallow roots represented most of the woody volume throughout the life cycle of the trees. The frame of the central part of the root system was almost completed in 4-year-old trees. Conclusions: In addition to the taproot, five types of lateral roots were identified in P. pinaster based on root geometry and size, and no consistent age effect was reported. This method could improve the connexion between root trait data and root modelling. [ABSTRACT FROM AUTHOR]

The root system architecture (RSA) of crops can affect their production, particularly in abiotic stress conditions, such as with drought, waterlogging, and salinity. Salinity is a growing problem worldwide that negatively impacts on crop productivity, and it is believed that yields could be improved if RSAs that enabled plants to avoid saline conditions were identified. Here, we have demonstrated, through the cloning and characterization of qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1), that a shallower root growth angle (RGA) could enhance rice yields in saline paddies. qSOR1 is negatively regulated by auxin, predominantly expressed in root columella cells, and involved in the gravitropic responses of roots. qSOR1 was found to be a homolog of DRO1 (DEEPER ROOTING 1), which is known to control RGA. CRISPR-Cas9 assays revealed that other DRO1 homologs were also involved in RGA. Introgression lines with combinations of gain-of-function and loss-of-function alleles in qSOR1 and DRO1 demonstrated four different RSAs (ultra-shallow, shallow, intermediate, and deep rooting), suggesting that natural alleles of the DRO1 homologs could be utilized to control RSA variations in rice. In saline paddies, near-isogenic lines carrying the qSOR1 loss-of-function allele had soil-surface roots (SOR) that enabled rice to avoid the reducing stresses of saline soils, resulting in increased yields compared to the parental cultivars without SOR. Our findings suggest that DRO1 homologs are valuable targets for RSA breeding and could lead to improved rice production in environments characterized by abiotic stress. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Root growth and development has become an important research topic for breeders and researchers based on a growing need to adapt plants to changing and more demanding environmental conditions worldwide. Over the last few years, genome-wide association studies (GWASs) became an important tool to identify the link between traits in the field and their genetic background. Here we give an overview of the current literature concerning GWASs performed on root system architecture (RSA) in plants. We summarize which root traits and approaches have been used for GWAS, mentioning their respective success rate towards a successful gene discovery. Furthermore, we zoom in on the current technical hurdles in root phenotyping and GWAS, and discuss future possibilities in this field of research. [ABSTRACT FROM AUTHOR]

Background and aims: Trait-based approaches are increasingly used to improve ecological restoration in degraded ecosystems. The aim of this study was to evaluate how vegetation controls soil detachment capacity (Dc) by concentrated flow based on the linkages between root traits and soil physics. Methods: We selected 60 plots along a land degradation gradient caused by long-term water erosion in a small catchment, central China. These plots consisted of woodlands, scrublands, grasslands and bare lands. And soil physical properties, root traits and Dc were measured in each plot. Results: Fine roots (0.2 mm < diameter < 2 mm) accounted for 51–93% of total root length in topsoil. Roots explained most of the soil variations in noncapillary porosity, aggregate stability and shear strength. Furthermore, our prediction model (R2 = 0.88, NSE = 0.85) showed that fine roots length density and soil shear strength were the primary factors reducing Dc. Conclusions: Vegetation restoration improves multiple soil physical properties key to mitigating Dc, and the root functional traits play a substantial role in this relationship. These findings could provide the basis for soil conservation, and for expanding the pool of species of interest, which can be used to provide erosion mitigation services in degraded ecosystems. [ABSTRACT FROM AUTHOR]

Soil drought occurrence during dry season has been the main constraint, besides prolonged flooding during rainy season, in increasing cropping intensity and rice productivity in tropical riparian wetland. Use of drought tolerant rice genotype might be a suitable option for overcoming such problem. This study focused on the effects of gradual soil drying during early vegetative growth stage on morphological and physiological traits of five Oryza glaberrima genotypes, namely RAM12, RAM14, RAM59, RAM97 and RAM101, and two Oryza sativa subsp japonica genotypes, i.e. Koshihikari and Minamihatamochi. The plants were subjected to 6 d of gradual soil drying condition from 15 days after transplanting (DAT) to 20 DAT, and were allowed to recover until 22 DAT. Gradual soil drying reduced plant growth as indicated by dry mass accumulation. Drought reduced stomatal conductance and increased leaf rolling score of all the genotypes. All the genotypes showed comparable response on stomatal conductance, but O. glaberrima genotypes performed higher in leaf rolling recovery. Meanwhile, O. sativa genotypes decreased total leaf area and specific leaf area, but increased specific leaf weight in order to avoid further damages due to drought stress. Drought tolerance mechanisms in RAM101, RAM12, RAM59 and RAM14 were associated with leaf morpho-physiological responses, root traits and dry biomass accumulation. [ABSTRACT FROM AUTHOR]