Root Architecture Parameters Research Articles

Inoculation of Bacillus sp. improves root architecture, gas exchange and efficiency of nutrient use in Corymbia seedlings

The inoculation of forest species with rhizobacteria growth promoters an increasing technology capable of improving the growth and also the final quality contributing to change robust and resistant originals. The objective was to evaluate growth, root architecture, gas exchange, chlorophyll a fluorescence, chlorophyll content and nutrient use efficiency in seedlings of Corymbia inoculated with the growth promoting rhizobacteria Bacillus sp. CCMD862. The growth promotion experiment was carried out in greenhouse, using hybrid clonal seedlings of Corymbia torelliana x Corymbia citriodora. The experimental design was CRD with 2 treatments (control and rhizobacteria Bacillus sp. CCMD862) with 5 replications for each treatment and 5 replicates per treatment (Bacillus sp. CCMD862 and Control - not inoculated). noculation promoted gains in gas exchange, chlorophyll fluorescence, nutrient use, biomass variables and in all root architecture parameters in relation to control. Biometric and biomass improvements resulted in higher DQI and a global growth promotion rate 30 % higher than control plants. The strain Bacillus sp. CCMD862 is able to biostimulate seedlings of Corymbia favoring the development of the root system, gains in the photosynthetic apparatus, increases in absorption and efficient use of nutrients that resulted in robust seedlings. The results obtained in this study must be confirmed in field conditions and the future development of an inoculant could assist with rooting in Corymbia, helping to reduce mortality in the field and obtain homogeneous commercial

Exogenous Easily Extractable Glomalin-Related Soil Protein Induces Differential Response in Plant Growth of Tea Plants via Regulating Water Channel Protein Expression

Glomalin, a glycoprotein secreted by arbuscular mycorrhizal fungi (AMFs), exhibits multiple beneficial functions in regard to plant growth. However, the roles and regulatory mechanisms of exogenous easily extractable glomalin-related soil protein (EE-GRSP) in water and their effects on the quality of tea plants (Camellia sinensis (L.) O. Ktze.) remain unclear. The present study aimed to investigate the effects of a quarter-strength exogenous EE-GRSP solution (1/4 EE-GRSP), half-strength exogenous EE-GRSP solution (1/2 EE-GRSP), three-quarter-strength exogenous EE-GRSP solution (3/4 EE-GRSP), and full-strength exogenous EE-GRSP solution (full EE-GRSP) on plant growth, the root system architecture, leaf water status, and the tea quality of tea seedlings, along with examining the changes in the relative expression of water channel proteins (AQPs) in tea plants. The results indicated that exogenous EE-GRSP of different strengths had different effects on both the growth performance (height, leaf numbers, and biomass) and root architecture parameters of tea seedlings, and the best positive effects on plant growth and the root architecture appeared under the three-quarter-strength exogenous EE-GRSP treatment. Similarly, the exogenous EE-GRSP application also differently affected tea quality indicators, in which only the quarter- and half-strength exogenous EE-GRSP solutions significantly increased most of the indicators, including carbohydrates, tea polyphenols, total amino acids, catechins, and flavonoids. Moreover, the half- and three-quarter-strength exogenous EE-GRSP treatments significantly increased the leaf relative water content (LRWC), but all of the exogenous EE-GRSP treatments significantly decreased the leaf water potential (LWP). Furthermore, the expression of AQP genes in the root system of tea plants was related to the strength of the exogenous EE-GRSP treatments, and different genes were significantly up-regulated or down-regulated under the treatment of exogenous EE-GRSP at different strengths. Moreover, the correlation analysis showed that most of the relative expression of AQPs was significantly and positively correlated with tea plant growth, the root architecture, and the leaf relative water content, but negatively correlated with tea quality indicators; however, the expression of CsNIPs and CsSIPs was markedly and negatively correlated with plant growth performance. Therefore, we speculated that the application of exogenous EE-GRSP could facilitate plant growth and improve the quality indirectly by regulating the expression of root AQPs, thus ameliorating the water uptake and nutrient accumulation in tea plants.

The selection of intra-inter specific Cucurbita rootstocks for grafted melon seedlings

This study was conducted to select promising Turkish local Cucurbita rootstocks among intraspecific and interspecific hybrids for grafted melon seedling based on hybrid success rate, hypocotyl traits and graft compatibility. Rooting potentials, root system architecture and plant growth parameters of the rootstocks grafted with melon were also evaluated. Two lines of C. maxima (male parent) and eleven lines of C. moschata (female parent) at S5 generation were used. In addition, six winter squash lines were used as male parent and six pumpkin lines were used as female parent in intraspecific hybridization program. Intraspecific hybrid combinations had quite high number of seeds per fruit as compared to interspecific hybrid combinations. The highest number of seeds per fruit was obtained from HMO2 × OMO2 (359) and OMO5 × HMO8 (314) hybrid combinations. Hypocotyl lengths of all hybrid cucurbit rootstock combinations ranged from 32.96 mm (RS17) to 73.35 mm (RS8) and hypocotyl thicknesses ranged from 2.71 mm (RS2) to 3.55 mm (RS8). Graft success rates varied between 96.6 – 100% in winter squash and pumpkin intraspecific hybrids and between 87.1 – 100% in interspecific hybrids. Significant differences were seen in root architecture parameters (root length, root volume, mean root diameter, root surface area and root dry matter weight) of intraspecific and interspecies hybrid Cucurbita lines. The findings of the study indicated that the intraspecific and interspecific local cucurbit rootstock candidates developed within the rootstock breeding program showed promise as viable options for commercial use as rootstocks for grafted melon seedlings. Research about the effects of selected intraspecific and interspecific hybrid Cucurbita rootstock candidates on earliness, fruit quality and yield parameters of grafted melon will continue.
 Keywords: Cucurbita maxima; Cucurbita moschata; Rootstock breeding; Root system architecture; Melon

Exogenous growth regulators amplify the morpho‐physiology, root architecture and dry‐matter accumulation in seed potato

AbstractEnhancing the productivity of seed potato production systems by improving the size of the tubers is a primary concern. Punjab, a state located in the northwest region of India, meets 60% of the country's seed requirements. In order to optimize the morpho‐physiological aspects, root structure, and overall yield of seed‐sized tubers, research trials were carried out at Punjab Agricultural University, Ludhiana over two consecutive years. The trial consisted of 11 different treatments and was conducted using a randomized complete block design with three replications. The application of Gibberellic acid at a concentration of 200 ppm, at 45 and 60 days after sowing (DAS), resulted in significantly higher yields of seed‐sized tubers measuring <4.5 cm. This treatment also exhibited superior root architecture parameters and accumulation of dry matter, outperforming all other growth regulation treatments. Compared to the untreated control group, the Gibberellic acid application led to a remarkable increase of 45.9% and 39.8% in seed‐sized tuber yields. Furthermore, it significantly boosted the protein, starch, antioxidant (total phenols), sugar (total and reducing), and mineral content (nitrogen, phosphorus, and potassium) in the tubers, surpassing the effects of all other growth regulation treatments. These results suggested that the exogenous use of gibberellic acid (200 ppm) at 45 and 60 DAS substantially improved the physiology, root architecture, and yield of seed‐sized tubers.

Plant-Derived Smoke Mitigates the Inhibitory Effects of the Auxin Inhibitor 2,3,5-Triiodo Benzoic Acid (TIBA) by Enhancing Root Architecture and Biochemical Parameters in Maize.

The present study was designed to investigate and compare the effects of plant-derived smoke (PDS) and auxin (IAA and IBA) on maize growth under the application of 2,3,5-triiodo benzoic acid (TIBA). For this purpose, indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA), each at a concentration of 10 ppm, along with PDS at a ratio of 1:500 (v/v) were used alone and in combination with 10 ppm of TIBA. The results indicate that the germination percentage (%) of maize seeds was enhanced under IAA, IBA and PDS treatment. However, IAA and IBA resulted in reduced germination when applied in combination with TIBA. Importantly, the germination percentage (%) was improved by PDS under TIBA treatment. The analysis of seedling height, length of leaves, and number of primary, seminal and secondary/lateral roots showed improvement under individual treatments of IAA and IBA, PDS and PDS + TIBA treatment, while these values were reduced under IAA + TIBA and IBA + TIBA application. Chlorophyll content, total soluble sugars and antioxidative enzymatic activity including POD and SOD increased in seedlings treated with PDS alone or both PDS and TIBA, while in seedlings treated with IAA and TIBA or IBA and TIBA, their levels were decreased. APX and CAT responded in the opposite way-under IAA, IBA and PDS treatment, their levels were found to be lower than the control (simple water treatment), while TIBA treatment with either IAA, IBA or PDS enhanced their levels as compared to the control. These results reveal that PDS has the potential to alleviate the inhibitory effects of TIBA. This study highlights the role of PDS in preventing TIBA from blocking the auxin entry sites.

Salinity Alleviation and Reduction in Oxidative Stress by Endophytic and Rhizospheric Microbes in Two Rice Cultivars.

Increased soil salinity poses serious limitations in crop yield and quality; thus, an attempt was made to explore microbial agents to mitigate the ill effects of salinity in rice. The hypothesis was mapping of microbial induction of stress tolerance in rice. Since the rhizosphere and endosphere are two different functional niches directly affected by salinity, it could be very crucial to evaluate them for salinity alleviation. In this experiment, endophytic and rhizospheric microbes were tested for differences in salinity stress alleviation traits in two rice cultivars, CO51 and PB1. Two endophytic bacteria, Bacillus haynesii 2P2 and Bacillus safensis BTL5, were tested with two rhizospheric bacteria, Brevibacterium frigoritolerans W19 and Pseudomonas fluorescens 1001, under elevated salinity (200 mM NaCl) along with Trichoderma viride as an inoculated check. The pot study indicated towards the presence of variable salinity mitigation mechanisms among these strains. Improvement in the photosynthetic machinery was also recorded. These inoculants were evaluated for the induction of antioxidant enzymes viz. CAT, SOD, PO, PPO, APX, and PAL activity along with the effect on proline levels. Modulation of the expression of salt stress responsive genes OsPIP1, MnSOD1, cAPXa, CATa, SERF, and DHN was assessed. Root architecture parameters viz. cumulative length of total root, projection area, average diameter, surface area, root volume, fractal dimension, number of tips, and forks were studied. Confocal scanning laser microscopy indicated accumulation of Na+ in leaves using cell impermeant Sodium Green™, Tetra (Tetramethylammonium) Salt. It was found that each of these parameters were induced differentially by endophytic bacteria, rhizospheric bacteria, and fungus, indicating different paths to complement one ultimate plant function. The biomass accumulation and number of effective tillers were highest in T4 (Bacillus haynesii 2P2) plants in both cultivars and showed the possibility of cultivar specific consortium. These strains and their mechanisms could form the basis for further evaluating microbial strains for climate-resilient agriculture.

Response characteristics of root to moisture change at seedling stage of Kengyilia hirsuta.

Kengyilia hirsuta is an important pioneer plant distributed on the desertified grassland of the Qinghai-Tibet Plateau. It has strong adaptability to alpine desert habitats, so it can be used as a sand-fixing plant on sandy alpine land. To study the response mechanisms of root morphological and physiological characteristics of K. hirsuta to sandy soil moisture, 10%, 25% and 40% moisture levels were set up through potted weighing water control method. The biomass, root-shoot ratio, root architecture parameters, and biochemical parameters malondialdehyde, free proline, soluble protein, indole-3-acetic acid, abscisic acid, cytokinin, gibberellin, relative conductivity and antioxidant enzyme activities were measured in the trefoil stage, and the response mechanisms of roots at different moisture levels were analyzed. The results showed that with the increase of soil moisture, root morphological indexes such as root biomass, total root length, total root volume and total root surface increased, while the root topological index decreased continuously. The malondialdehyde content, relative conductivity, superoxide dismutase activity, peroxidase activity, catalase activity, free proline content, soluble protein content, abscisic acid content and cytokinin content at the 25% and 40% moisture levels were significantly decreased compared with the 10% level (P< 0.05). Thus, the root growth of K. hirsuta was restricted by the 10% moisture level, but supported by the 25% and 40% moisture levels. An artificial neural network revealed that total root length, total root surface area, root link average length, relative conductivity, soluble protein, free proline and moisture level were the key factors affecting root development. These research results could contribute to future agricultural sustainability.

Root architecture characteristics of five natural homogeneous grasslands in riparian buffers from lower reaches of Yellow River

AbstractRoot system characteristics are of fundamental importance to soil improvement and underground resource acquisition in riparian buffer strips. Root architectural traits determine the in situ space‐filling properties of a root system. The aims of this study were to examine the grassland root morphological characteristics in the vegetation zone from the lower reaches of Yellow River. Five natural homogeneous grasslands including Imperata cylindrica, Phragmites australis, Cynodon dactylon, Artemisia argyi and Juncellus serotinus were selected. Seven root architecture parameters including fractal dimension, total root length, total root surface area, total root volume, average diameter, root crossing number and root tip number were analyzed, and comprehensive scores were evaluated using principal component analysis. The results showed that average root diameter of the five herbaceous plants was ranged from 0.42 to 0.78 mm. The total root length, total root surface area, total root volume, root crossing number and root tip number of I. cylindrica and P. australis were significantly higher than those of C. dactylon, A. argyi and J. serotinus. The main factors influencing root architecture were average diameter, total root surface area and total root volume through principal component analysis. I. cylindrica had the highest comprehensive score, followed by P. australis, A. argyi, C. dactylon and J. serotinus. I. cylindrica and P. australis would be good competitors for both soil resource acquisition and soil quality improvement due to their root traits. These results could provide a scientific basis for evaluating the ecological function of riparian vegetation.

Trade-offs in Root and Shoot Growth in Forage Pea [Pisum sativum (L.) arvense] with Foliar Applications of Synthetic Elicitor DPMP (2,4-Dichloro-6-{(E)-[(3-Methoxyphenyl) Imino] Methyl} Phenol) and SA (Salicylic Acid)

Background: Climate change, abiotic and biotic stress pressure are forcing breeders and farmers to find alternative ways to improve and extend food production. Even though there are multiple ways to cope with stress conditions, alleviation of the stress by enhancing plant responses is one of the cheapest, environmentally safest and most direct ways. This study aimed to evaluate the effects of two common plant defense elicitors, 2,4-dichloro-6-{(E)-[(3-methoxyphenyl) imino] methyl} phenol (DPMP) and salicylic acid (SA) on plant growth and seedling vigor with forage pea [Pisum sativum (L.) arvense] as a model plant. Methods: Two different chemicals, 100 µM SA and 10 µM DPMP were evaluated in response to Polyethylene glycol 8000 (PEG) treatment in a semi-hydroponic growth system. Root architecture and shoot growth parameters were evaluated. The experiment was designed according to completely randomized design with three replications and ten plants per replication. Result: The effects of SA and DPMP foliar applications were significant on tap, lateral and total root lengths, number of lateral roots and root fresh weight. For most of the traits, SA and DPMP did not inhibit plant growth compared to control under treated and untreated conditions. Average lateral root length (aLatRL) was the noteworthy trait with significantly higher values in DPMP + unstressed conditions. Plants sprayed with DPMP had significantly higher (5.57 cm plant-1) aLatRL values compared to SA (4.53 cm plant-1) and control (3.01 cm plant-1). The results of the current study suggest that SA and DPMP foliar spraying can be beneficial to reduce the effects of abiotic stresses at optimal doses defined for each species. DPMP can be a candidate as a sustainable pesticide alternative and growth-enhancing agent, similar to SA.

干旱胁迫对不同根型苜蓿根系构型的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 干旱胁迫对不同根型苜蓿根系构型的影响 DOI: 10.5846/stxb202109042504 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（32160327）；甘肃省重点研发计划项目（20YF3FA011） Effects of drought stress on root architecture of different root- type alfalfa Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:采用盆栽试验，比较播种当年及生长第2年对照、中度、重度干旱胁迫下根茎型、直根型、根蘖型苜蓿根系平面、立体几何构型和分形特征差异，以探究不同根型苜蓿对干旱的适应策略。结果表明：随干旱胁迫增加，各根型苜蓿根系总长度、总表面积、总体积和平均直径均减小；各根型苜蓿的根系拓扑指数较小，根系分支模式为叉状分支结构；各根型苜蓿的根系具有较好的分形特征，其分形维数较小，而分形丰度和平均连接长度均较大，表明其根系分支相对简单，但空间拓展能力强，有利于对营养空间的占有；各根型苜蓿的总分支较小、逐级分支率较大，有助于资源的快速获取和促进主根的向下生长。对根系构型参数进行主成分分析，根系总表面积、分形丰度、根长、根体积、分形维数和比根长6个根系构型参数能较好反映不同根型苜蓿根系构型特征。重度胁迫下，根茎型、根蘖型苜蓿的根系总长度、总表面积、总体积、比根长、比表面积、平均连接长度均大于直根型苜蓿，表明根茎型、根蘖型苜蓿适应干旱环境的能力强于直根型苜蓿。 Abstract:To investigate the ecological adaptation strategies of drought stress on root plane and stereo geometry architecture and fractal characteristics, pot experiment using three root types of alfalfa (rhizomatous rooted Medicago sativa ‘Qingshui’, tap rooted M. sativa ‘Longdong’, creeping rooted M. varia Martin. ‘Gongnong’ No.4) as the experimental materials was conducted to set up the drought treatment experiments. The results showed that the total root length, total surface area, total root volume and root average diameter of different root-type alfalfa decreased with increasing of drought concentration. The root topological indices of different root-type alfalfa were small, and the root branching patterns were herring-bone-like. The roots of different root-type alfalfa had obviously fractal characteristics, and the fractal dimension was small, while the fractal abundance and the average link length were large, which indicated that they had simple root architecture and high ability to expand living space. Smaller branching ratio and larger stepwise branching rate of different root-type alfalfa were helpful to speed resource acquisition and promote taproot growth downward. Root architecture parameters were analyzed by the principal component analysis. The parameters of total surface area, fractal abundance, total root length, total root volume, fractal dimension, and specific root length could well present the root architecture characteristics of different root-type alfalfa. Under severe stress, the total root length, total surface area, total root volume, specific root length, and specific surface area of rhizomatous rooted and creeping rooted alfalfa were higher than tap rooted alfalfa, which showed that the adaptation to drought environment of rhizomatous rooted and creeping rooted alfalfa were stronger than that of tap rooted alfalfa. 参考文献 相似文献 引证文献

Detection of Root Physiological Parameters and Potassium and Calcium Currents in the Rhizoplane of the Apple Rootstock Superior Line 12-2 With Improved Apple Replant Disease Resistance.

The cultivation of resistant rootstocks is one of the more effective ways to mitigate apple replant disease (ARD). We performed an ion current test, a pot experiment, and a pathogen infection test on the apple rootstocks 12-2 (self-named), T337, and M26. The ion current test showed that exposure to ARD soil extract for 30 min had a significant effect on K+ ion currents at the meristem, elongation, and mature zones of the M26 rhizoplane and on Ca2+ currents in the meristem and elongation zones. ARD also had a significant effect on Ca2+ currents in the meristem, elongation, and mature zones of the T337 rhizoplane. Exposure to ARD soil extract for 5 min had a significant effect on K+ currents in the meristem, elongation, and mature zones of 12-2 and on the Ca2+ currents in the elongation and mature zones. Compared to a 5-min exposure, a 30-min exposure to ARD extract had a less pronounced effect on K+ and Ca2+ currents in the 12-2 rhizoplane. The pot experiment showed that ARD soil had no significant effect on any root architectural or physiological parameters of 12-2. By contrast, ARD soil significantly reduced some root growth indices and the dry and fresh weights of T337 and M26 compared with controls on sterilized soil. ARD also had a significant effect on root metabolic activity, root antioxidant enzyme activity (except superoxide dismutase for T337), and malondialdehyde content of T337 and M26. Pathogen infection tests showed that Fusarium proliferatum MR5 significantly affected the root structure and reduced the root metabolic activity of T337 and M26. It also reduced their root antioxidant enzyme activities (except catalase for T337) and significantly increased the root malondialdehyde content, reactive oxygen levels, and proline and soluble sugar contents. By contrast, MR5 had no such effects on 12-2. Based on these results, 12-2 has the potential to serve as an important ARD-resistant rootstock.

Phenotyping seedlings for selection of root system architecture in alfalfa (Medicago sativa L.)

BackgroundThe root system architecture (RSA) of alfalfa (Medicago sativa L.) affects biomass production by influencing water and nutrient uptake, including nitrogen fixation. Further, roots are important for storing carbohydrates that are needed for regrowth in spring and after each harvest. Previous selection for a greater number of branched and fibrous roots significantly increased alfalfa biomass yield. However, phenotyping root systems of mature alfalfa plant is labor-intensive, time-consuming, and subject to environmental variability and human error. High-throughput and detailed phenotyping methods are needed to accelerate the development of alfalfa germplasm with distinct RSAs adapted to specific environmental conditions and for enhancing productivity in elite germplasm. In this study methods were developed for phenotyping 14-day-old alfalfa seedlings to identify measurable root traits that are highly heritable and can differentiate plants with either a branched or a tap rooted phenotype. Plants were grown in a soil-free mixture under controlled conditions, then the root systems were imaged with a flatbed scanner and measured using WinRhizo software.ResultsThe branched root plants had a significantly greater number of tertiary roots and significantly longer tertiary roots relative to the tap rooted plants. Additionally, the branch rooted population had significantly more secondary roots > 2.5 cm relative to the tap rooted population. These two parameters distinguishing phenotypes were confirmed using two machine learning algorithms, Random Forest and Gradient Boosting Machines. Plants selected as seedlings for the branch rooted or tap rooted phenotypes were used in crossing blocks that resulted in a genetic gain of 10%, consistent with the previous selection strategy that utilized manual root scoring to phenotype 22-week-old-plants. Heritability analysis of various root architecture parameters from selected seedlings showed tertiary root length and number are highly heritable with values of 0.74 and 0.79, respectively.ConclusionsThe results show that seedling root phenotyping is a reliable tool that can be used for alfalfa germplasm selection and breeding. Phenotypic selection of RSA in seedlings reduced time for selection by 20 weeks, significantly accelerating the breeding cycle.

Genetics components of rice root architecture and carbon isotopic fractionation parameters: a tracer for breeding in a water-saving irrigation management

Phenotyping is the major bottleneck in the effort to develop varieties of rice (Oryza sativa L.) suitable for growing under a water-saving irrigation management, such as alternate wetting and drying irrigation techniques (AWD). To analyze if the genotypic variability for carbon isotope discrimination (CID) in rice leaves could be used as a relatively high-throughput tracer to early select superior genotypes highlighting improved root architecture traits when submitted to AWD, a set of twenty varieties grown under semi-natural conditions were submitted to two water irrigation regimes, continuous flooding (CF) and AWD cycles. Coefficients of genetic variance (π2g) obtained for root architecture, micro-morphological and physiological traits were significant for all of them regardless of the adopted irrigation system, except to mean root diameter. The three significant principal components (PCs) with eigenvalue > 1, explain most of the total variation across cycles and water regimes. For most of analyzed traits, the values of heritability coefficients were higher regardless of adopted irrigation management and trait category; for CID, the magnitudes of broad heritability at an individual level (greater than 0.80) were similar in the two irrigation techniques, evidencing that the success of the selection is independent of irrigation management. The higher CID values after three AWD cycles are associated with varieties with higher total root length and volume. To our knowledge, this is the first study demonstrating the potential application of CID as a tracer to select root architecture traits in rice when water-saving irrigation management is of concern.

Bayesian inference of root architectural model parameters from synthetic field data

Background and aimsCharacterizing root system architectures of field-grown crops is challenging as root systems are hidden in the soil. We investigate the possibility of estimating root architecture model parameters from soil core data in a Bayesian framework.MethodsIn a synthetic experiment, we simulated wheat root systems in a virtual field plot with the stochastic CRootBox model. We virtually sampled soil cores from this plot to create synthetic measurement data. We used the Markov chain Monte Carlo (MCMC) DREAM(ZS) sampler to estimate the most sensitive root system architecture parameters. To deal with the CRootBox model stochasticity and limited computational resources, we essentially added a stochastic component to the likelihood function, thereby turning the MCMC sampling into a form of approximate Bayesian computation (ABC).ResultsA few zero-order root parameters: maximum length, elongation rate, insertion angles, and numbers of zero-order roots, with narrow posterior distributions centered around true parameter values were identifiable from soil core data. Yet other zero-order and higher-order root parameters were not identifiable showing a sizeable posterior uncertainty.ConclusionsBayesian inference of root architecture parameters from root density profiles is an effective method to extract information about sensitive parameters hidden in these profiles. Equally important, this method also identifies which information about root architecture is lost when root architecture is aggregated in root density profiles.

A metabolomics insight into the Cyclic Nucleotide Monophosphate signaling cascade in tomato under non-stress and salinity conditions

Cyclic Nucleotides Monophosphate (cNMP) are key signalling compounds whose role in plant cell signal transduction is still poorly understood. In this work we used sildenafil, a phosphodiesterase (PDE) inhibitor used in human, to amplify the signal cascade triggered by cNMP using tomato as model plant. Metabolomics was then used, together with plant growth and root architecture parameters, to unravel the changes elicited by PDE inhibition either under non-stress and 100 mM NaCl salinity conditions.The PDE inhibitor elicited a significant increase in biomass (+62 %) and root length (+56 %) under no stress conditions, and affected root architecture in terms of distribution over diameter classes. Together with cGMP, others cNMP were modulated by the treatment. Moreover, PDE inhibition triggered a broad metabolic reprogramming involving photosynthesis and secondary metabolism. A complex crosstalk network of phytohormones and other signalling compounds could be observed in treated plants. Nonetheless, metabolites related to redox imbalance processes and NO signalling could be highlighted in tomato following PDE application. Despite salinity damped down the growth-promoting effects of sildenafil, interesting implications in plant mitigation to stress-related detrimental effects could be observed.

Pixel level segmentation of early-stage in-bag rice root for its architecture analysis

The root architecture parameters are important to the study of plant growth state and the segmentation of plant roots is the key to the measurement of these parameters. Most existing methods use the threshold calculated by different algorithms to segment the roots in a grayscale image, which requires a low noise background. We designed a set of automatic equipment to record the roots images of rice seedlings planted in transparent bags. Those root images contain strong noise and it makes existing methods invalid in our circumstances. To solve the segmentation problem of rice roots under strong noise, we proposed a convolutional neural network based on U-Net and SE-ResNet. The root images were preprocessed and cropped into small patches to fit CNN input requirements. Experiments have shown that our method performs effectively in pixel-level segmentation of rice seedling roots that contain tiny lateral roots. Our method achieves an intersection over union (IoU) of 87.4%. This method provides a new approach to automatic and fast pixel-level root segmentation, which is of great importance for the analysis of root morphology.

Melatonin Mitigates Nickel Toxicity by Improving Nutrient Uptake Fluxes, Root Architecture System, Photosynthesis, and Antioxidant Potential in Tomato Seedling

Globally, crop production has been widely threatened by contamination of arable lands with heavy metals including Nickel (Ni). Stress-relief molecule melatonin (ME) has been widely used to mitigate the phytotoxicity induced by heavy metals. The current study aimed to explore the response to Ni stress and the alleviating role of ME in boosting Ni-stress tolerance in tomato seedlings. The roots of tomato seedlings pretreated with ME (100 μM) for 3 days, followed by applied Ni (50 μM) for 7 days. The treatments were composed of (1) control (CK); (2) melatonin (ME, 100 μM); (3) nickel (Ni, 50 μM); and (4) melatonin and nickel treatment (ME+Ni, 100 μM + 50 μM). Nickel toxicity noticeably inhibited plant growth and biomass production by impairing the root architecture, photosynthesis process, nutrient uptake, and antioxidant enzymes. Conversely, ME-supplementation inhibited Ni-induced growth damage, improved root architecture, nutrient uptake, pigment contents, and leaf gas exchange parameters, and decreased Ni-accumulation. Furthermore, the electrolyte leakage (EL), malondialdehyde (MDA) content, and reactive oxygen species (ROS) accumulation were significantly reduced in ME-treated seedlings via improving antioxidant enzyme activity as well as upregulation of their encoding gene expression. In conclusion, our findings provide a shred of substantial evidence that ME improved Ni-induced phytotoxicity in tomato seedlings, mainly by improving the root architecture, biomass production, mineral homeostasis (reducing nickel accumulation in plants), and photosynthetic efficiency.

Determination of root properties of saplings belong to two boxwood species (Buxus sempervirens and Buxus balearica) by image processing technique

The study was carried out to determine the root architectural characteristics of the one-year saplings of two species of boxwood (Buxus sempervirens L. and Buxus balearica Lam.), which are endangered and natural plants of Turkey, in the greenhouse environment using the WinRhizo root analysis program and scanner. Total root length (cm), root surface area (cm2), root volume (cm3), average root diameter (mm), number of tips, number of forks and number of root crossings were determined in the study. According to the results of the study, the increase in temperature and decrease in humidity values in the second year of both species were effective on the root architectural features. As a result of this effect, the second year root length (3810 cm), number of root tips (2299), number of forks (7007) and number of root crossings (696) increased, root diameter (1.4 mm), root surface area (2158 cm2) and root volume (8 cm3) decreased. As a result, it has been concluded that species can make changes in their root parameters to adapt to different conditions and their adaptability is high. In general, the best results in root architectural parameters were obtained from Buxus balearica on the basis of species.

Root growth, architecture, and ion uptake of alfalfa and triticale irrigated with brackish groundwater and reverse osmosis concentrate

AbstractSoil salinity is a major environmental constraint for agricultural production, especially in arid and semiarid regions of the world. Salts in irrigation water and soil can potentially harm plant root growth. To date, more research has been devoted to aboveground biomass production. This study is aimed at determining the impacts of irrigating with brackish groundwater (BGW) and reverse osmosis (RO) concentrate on the root and shoot biomass, root/shoot ratio (R:S), and root system architecture (RSA) of alfalfa (Medicago sativa L.) and triticale (× Triticosecale Wittm. ex A. Camus). Two replicated experiments were conducted in the Fabian Garcia Science Center (FGSC) greenhouse from 7 Oct. 2017 to 7 Jan. 2018 in Las Cruces, NM, USA. After 90 d, roots were scanned using a WinRHIZO image analysis system and the data were analyzed. In both the species, RO and BGW + NaCl increased root Na+ and Cl– concentrations. Triticale behaved more like a root Na‐retaining species than alfalfa but with an associated decrease in total root biomass. Irrigation with BGW in alfalfa increased root length and the number of forks and crossings, whereas RO irrigation increased root length density (RLD). Unlike alfalfa, triticale root architectural parameters were largely unaffected by salinity. However, RO and BGW + NaCl waters promoted significantly (p ≤ .05) higher shoot biomass in triticale than the control and BGW alone. Our findings recommend BGW for alfalfa irrigation, and triticale as a potential future forage crop for dry and saline conditions.

Hydrological connectivity improves soil nutrients and root architecture at the soil profile scale in a wetland ecosystem

Hydrological connectivity is an essential driver of the stability, structure, and function of wetland ecosystems. Small-scale hydrological connectivity restricts large-scale hydrological cycle processes. This study aimed to investigate the response of soil and root properties to hydrological connectivity at the soil profile scale. Tamarix chinensis, which is a typical plant of the Yellow River Delta wetland, was sampled for analysis. We investigated soil and root properties in the three study plots where T. chinensis distributed and compared them at different soil depths and under different hydrological connectivity conditions. We found that the soil organic carbon (SOC), soil organic matter (SOM), and soil total nitrogen (STN) were significantly higher in shallow soil (0–10 cm deep), and that root architecture parameters such as root length and width at soil depth of 0–10 cm were also significantly higher than at other soil depths. Both the soil nutrients and root architecture parameters were significantly influenced by hydrological connectivity. Specifically, SOC, SOM, and STN were significantly higher in regions of high hydrological connectivity than in regions of low hydrological connectivity. Additionally, root length, root surface area, root projected area, and root volume were markedly higher in regions of high hydrological connectivity. Furthermore, root length and width had significant positive correlations with both SOC and SOM in regions of high hydrological connectivity. Taken together, these results indicate that higher hydrological connectivity promotes soil nutrients and root architecture at the soil profile scale. In the process of wetland protection and restoration, we should not only pay attention to hydrological connectivity at a watershed scale, but also to improving hydrological connectivity at smaller scales so as to restore soil nutrients and promote plant growth.