Root Elongation Rate Research Articles

4D Structural root architecture modeling from digital twins by X-Ray Computed Tomography

BackgroundBreakthrough imaging technologies may challenge the plant phenotyping bottleneck regarding marker-assisted breeding and genetic mapping. In this context, X-Ray CT (computed tomography) technology can accurately obtain the digital twin of root system architecture (RSA) but computational methods to quantify RSA traits and analyze their changes over time are limited. RSA traits extremely affect agricultural productivity. We develop a spatial–temporal root architectural modeling method based on 4D data from X-ray CT. This novel approach is optimized for high-throughput phenotyping considering the cost-effective time to process the data and the accuracy and robustness of the results. Significant root architectural traits, including root elongation rate, number, length, growth angle, height, diameter, branching map, and volume of axial and lateral roots are extracted from the model based on the digital twin. Our pipeline is divided into two major steps: (i) first, we compute the curve-skeleton based on a constrained Laplacian smoothing algorithm. This skeletal structure determines the registration of the roots over time; (ii) subsequently, the RSA is robustly modeled by a cylindrical fitting to spatially quantify several traits. The experiment was carried out at the Ag Alumni Seed Phenotyping Facility (AAPF) from Purdue University in West Lafayette (IN, USA).ResultsRoots from three samples of tomato plants at two different times and three samples of corn plants at three different times were scanned. Regarding the first step, the PCA analysis of the skeleton is able to accurately and robustly register temporal roots. From the second step, several traits were computed. Two of them were accurately validated using the root digital twin as a ground truth against the cylindrical model: number of branches (RRMSE better than 9%) and volume, reaching a coefficient of determination (R2) of 0.84 and a P < 0.001.ConclusionsThe experimental results support the viability of the developed methodology, being able to provide scalability to a comprehensive analysis in order to perform high throughput root phenotyping.

Abscisic acid is required for root elongation associated with Ca2+ influx in response to water stress

Abscisic acid (ABA) is a critical hormone for plant survival upon water stress. In this study, a large-scale mutants of Arabidopsis ecotype Columbia-0 (Col-0) by ethyl methanesulfonate (EMS)-mutagenesis were generated, and an improved root elongation under water-stress 1 (irew1) mutant showing significantly enhanced root growth was isolated upon a water potential gradient assay. Then, irew1 and ABA-related mutants in Arabidopsis or tomato plants were observed under water potential gradient assay or water-deficient condition. ABA pathway, Ca2+ response and primary root (PR) elongation rate were monitored in addition to DNA- and RNA-Seq analyses. We found that based on phenotyping and transcriptional analyses, irew1 exhibited the enhanced PR growth, ABA and Ca2+ responses compared to wild-type subjected to water stress. Interestingly, exogenous Ca2+ application enhanced PR growth of irew1, ABA-biosynthesis deficient mutants in Arabidopsis and tomato plants in response to water potential gradients or water-deficient condition. In combination with other ABA-related mutants and pharmacological study, our results suggest that ABA is required for root elongation associated with Ca2+ influx in response to water stress.

Sinapis alba L. and Triticum aestivum L. as biotest model species for evaluating municipal solid waste leachate toxicity

The volume of municipal solid waste (MSW) inputs is rapidly increasing with a growing human population, and its composition is changing due an increased diversity of materials being deposited. There is an associated increase in leachate, a common toxic byproduct of MSW facilities that must be collected and treated prior to its release into the environment. There is growing interest in plant-based methods that are economical and efficient for leachate toxicity assessment such as biological tests that use indicator species. In the present study, the tolerance thresholds of two herbaceous species, Sinapis alba L. (mustard) and Triticum aestivum L. (wheat) to increasing shares of leachate sourced from an MSW facility in the Czech Republic were assessed through a variety of physiological parameters. Soil-based biotests showed a stimulation in the shoot biomass, leaf expansion, primary root elongation and carbon assimilation rate of the selected plant species to leachate concentrations between 20 and 50 %. Higher leachate concentrations led to reductions in most physiological parameters, especially the elongation of seedling roots when growth solutions with >50 % leachate were applied. While S. alba was more sensitive to increasing proportions of leachate in terms of growth parameters of the shoot tissues, photosystem II efficiency and chlorophyll pigment concentrations were more responsive in T. aestivum, indicating species-dependent differences. The present biotests provide further support for the use of both Sinapis alba L and Triticum aestivum L. as indicator species of phytotoxicity.

Responses of barley genotypes for salt tolerance under in vitro culture condition

An experiment was undertaken at Agricultural Botany Laboratory, Patuakhali Science and Technology, to screen out salt tolerant barley (Hordeum vulgare L.) genotypes. The evaluation was done based on germination percentage, shoot length, root length and shoot: root ratio. Five barley genotypes including BARI barley 2, BARI barley 3, BARI barley 4, BARI barley 5 and BARI barley 7 were used in the screening program. The barley genotypes were grown in eight levels NaCl solution like 0(Control), 20, 40, 60, 80, 100 and 120 mM. The present study shows that salinity reduced germination percentage of barley and the extent of reduction increased with the increase in the concentration of salinity in the growth medium. Shoot dry weight (1.40 mg), root dry weight (0.21 mg), shoot moisture content (80.0%), root elongation rate (1.81), vigor index (21.30), speed of germination (7.91) and root length (21.67 cm) were obtained from the variety BARI barley 4 with 80 mMNaCL (V3T4). Based on the growth attributes the genotypes BARI barley 7 and BARI barley 4 were found tolerant to salt stress as they grown up to 60 mM and 80 mMNaCl solution respectively. The genotypes BARI barley 4 was therefore selected to be grown in south coastal saline soil of Bangladesh.&#x0D; Progressive Agriculture 32 (1): 1-9, 2021

In situ laser manipulation of root tissues in transparent soil

AimsLaser micromanipulation such as dissection or optical trapping enables remote physical modification of the activity of tissues, cells and organelles. To date, applications of laser manipulation to plant roots grown in soil have been limited. Here, we show laser manipulation can be applied in situ when plant roots are grown in transparent soil.MethodsWe have developed a Q-switched laser manipulation and imaging instrument to perform controlled dissection of roots and to study light-induced root growth responses. We performed a detailed characterisation of the properties of the cutting beams through the soil, studying dissection and optical ablation. Furthermore, we also studied the use of low light doses to control the root elongation rate of lettuce seedlings (Lactuca sativa) in air, agar, gel and transparent soil.ResultsWe show that whilst soil inhomogeneities affect the thickness and circularity of the beam, those distortions are not inherently limiting. The ability to induce changes in root elongation or complete dissection of microscopic regions of the root is robust to substrate heterogeneity and microscopy set up and is maintained following the limited distortions induced by the transparent soil environment.ConclusionsOur findings show that controlled in situ laser dissection of root tissues is possible with a simple and low-cost optical set-up. We also show that, in the absence of dissection, a reduced laser light power density can provide reversible control of root growth, achieving a precise “point and shoot” method for root manipulation.

Genotypic Variability in Architectural Development of Mungbean (Vigna radiata L.) Root Systems and Physiological Relationships With Shoot Growth Dynamics.

Selection for root system architectures (RSA) to match target growing environments can improve yields through better adaptation to water and nutrient-limiting conditions in grain legume crops such as mungbean. In this study, the architectural development of root systems in four contrasting mungbean varieties was studied over time to explore their relationships to above-ground growth and development. Key findings suggested that early maturing mungbean varieties were characterized by more rapid root elongation rates and leaf area development, resulting in more vigorous root and shoot growth during early growth stages compared with a late maturing variety. The early maturing varieties also showed root morphological traits generally adapted to water-limited environments, such as deeper, longer and lighter roots. Early maturing varieties more rapidly colonized the top 10–20 cm of the soil profile during early growth stages, whereas the later maturing variety developed less prolific but 20–50% thicker roots in the same profile layers in later stages of crop growth. The diversity of root characteristics identified in these commercial varieties suggests that there are opportunities to combine desirable root traits with maturity types to target different production environments. Examples include deeper, longer, and thinner roots for crops to exploit deep profile reserves of water and nutrients, and thicker and shallower root systems for crops grown in shallow soils with stratified nutrient reserves and/or more favorable in-season rainfall.

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.

How do water, compaction and heat stresses affect soybean root elongation? A review

Soil physical limitations that affect directly crop root elongation are the water, heat and mechanical stresses. In the literature, there are few studies that present a clear relationship of root elongation rate and soil physical stresses that could be used into a root growth models. The aim of this study was to carry out a systematic review, compiling and analyzing the impacts of the physical limitations of the soil (water stress, heat stress and soil strength) on the root elongation rate of soybean. The PRISMA method was used to select scientific papers published in the Scopus and Web of Science databases. The terms "root elongation", "soybean", "Glycine max", "water stress", "mechanical impedance", "heat stress", "hypoxia", "soil penetration resistance", "matric potential" and "temperature" were used as selection criteria. These procedures resulted only in ten papers, which were published until June 2021. The results indicate that the soybean root elongation was increased due to the increase in soil temperature, until 30 °C. Soil penetration resistance reduce exponentially the root elongation, and 4 MPa was sufficient to slow root elongation to approximately 7% of its unimpeded rate. The root elongation decay exponentially due to the reduction of the water potential. Even though soil compaction, heat stress, and water potential are relevant factors that affect directly the soybean root elongation, very few studies have published comparisons of the root responses to soil physical condition for soybean.

Genotypic diversity and plasticity of root system architecture to nitrogen availability in oilseed rape.

In the emerging new agricultural context, a drastic reduction in fertilizer usage is required. A promising way to maintain high crop yields while reducing fertilizer inputs is to breed new varieties with optimized root system architecture (RSA), designed to reach soil resources more efficiently. This relies on identifying key traits that underlie genotypic variability and plasticity of RSA in response to nutrient availability. The aim of our study was to characterize the RSA plasticity in response to nitrogen limitation of a set of contrasted oilseed rape genotypes, by using the ArchiSimple model parameters as screening traits. Eight accessions of Brassica napus were grown in long tubes in the greenhouse, under two contrasting levels of nitrogen availability. After plant excavation, roots were scanned at high resolution. Six RSA traits relative to root diameter, elongation rate and branching were measured, as well as nine growth and biomass allocation traits. The plasticity of each trait to nitrogen availability was estimated. Nitrogen-limited plants were characterized by a strong reduction in total biomass and leaf area. Even if the architecture traits were shown to be less plastic than allocation traits, significant nitrogen and genotype effects were highlighted on each RSA trait, except the root minimal diameter. Thus, the RSA of nitrogen-limited plants was primarily characterised by a reduced lateral root density, a smaller primary root diameter, associated with a stronger root dominance. Among the RSA traits measured, the inter-branch distance showed the highest plasticity with a level of 70%, in the same range as the most plastic allocation traits. This work suggests that lateral root density plays the key role in the adaptation of the root system to nitrogen availability and highlights inter-branch distance as a major target trait for breeding new varieties, better adapted to low input systems.

Electrical properties of plant root cell plasma membrane influence the alleviation of Al and Cu phytotoxicity by Ca and Mg cations.

Although it is known that cations such as calcium (Ca) and magnesium (Mg) can alleviate metal toxicity in plants, much uncertainty remains regarding the mechanisms by which this alleviation occurs. In this study, three plant species, cowpea (Vigna unguiculata. cv. White Caloona), soybean (Glycine max. cv. Bunya), and wheat (Triticum. cv. Axe), were used to examine growth in nutrient solutions containing a series of cations (Ca and Mg) and toxicants (Al and Cu). The addition of Ca and Mg increased Al3+ activities that induced 50% plant root elongation rate decline (EC50) from 4.0, 4.2, 0.34 to 31, 22, 9.4 for cowpea, soybean, wheat respectively. However, when expressed as the Al3+ activity at the root-cell plasma membrane (PM) surface, the addition of Ca and Mg increased Al sensitivity. In regression models, plant root elongation rate (RER) had higher R2 values with Al3+ activity at the PM than with Al3+ activity in the bulk solutions (0.60, 0.58, 0.93 for cowpea, soybean, wheat respectively). For Cu, the addition of Ca and Mg alleviated its phytotoxicity when expressed as the Cu2+ activity in the bulk-phase solutions for both cowpea and wheat. However, in soybean, the addition of Mg did not alter Cu toxicity when expressed as the Cu2+ bulk activity. Generally, the metal activity at the outer PM surface of the root cells is a better predictor for their phytotoxicity than the activity in bulk solution (R2=0.80, 0.80, 0.87 for cowpea, soybean, wheat respectively). These results supported the concept that the strength of alleviation of Ca and Mg cations depends on both the plant species and the toxicants that they alleviate. The different mechanisms should be fully considered in relevant assessments of trace metal toxicity in plants.

Reversible and irreversible root phenotypic plasticity under fluctuating soil physical conditions

Roots grow in a highly heterogeneous physical environment due to the spatial complexity of soil structure. Thereby, the root growth zone repeatedly experiences soil physical stress such as hypoxia or increased penetration resistance. To mimic the highly variable physical environment surrounding the root growth zone, we subjected pea and wheat seedlings to periodic soil physical stress. One day of soil hypoxia or increased penetration resistance reduced root elongation rate of both species by at least 20 %. Upon stress release, root elongation rate of pea could recover within one day, while no such recovery occurred in wheat. Similarly, the diameter of the root elongation zone in pea increased by 15 % and 20 % due to hypoxia and increased penetration resistance, respectively, but decreased again once the stresses were released. In contrast, the diameter of the elongation zone of wheat roots started to decrease with the onset of soil physical stress and this trend continued upon stress release. Hence, root responses to short-term soil physical stress were reversible in pea and irreversible in wheat, indicating reversible and irreversible root phenotypic plasticity, respectively. This suggests that strategies to cope with periodic soil physical stress may vary among species. The differentiation between reversible and irreversible phenotypic plasticity is crucial to advance our understanding on soil exploration, resource acquisition, whole plant growth, and ultimately crop yield formation on structured soil.

A method for continuously monitoring the quality of Masson pine seedlings.

Root growth potential (RGP) is a popular physiological indicator used to evaluate seedling vigor. However, the time scale used in the RGP test is the order of days, which leads to poor performance of the RGP method. We propose an optical interference method, called statistical interferometry, to measure minute root elongation at a sub-nanometer scale, which can decrease the time used in measuring RGP. The time scale of this method is also 104 times less than that of the RGP method. Because we can measure the length of root elongation continuously, we can compute the root elongation rate (RER), which is the variety of the length of root elongation per second. Continuous monitoring can help determine the quality of Masson pine seedling as soon as possible. To show the effectiveness of our proposed method, we designed an experiment, in which we applied different water stresses to our collected Masson pine seedlings and acquired two groups of pines, representing two different qualities: one stressed by water and one not. After measuring the RER of the groups in our experiments, we found that RER is interrelated with the quality of seedlings.

Leaf and root traits, but not relationships among traits, vary with ontogeny in seedlings

Although leaf and root traits may change considerably throughout plant development, ontogenetic variation is rarely considered in trait-based ecology. Studies focused on how morphological root traits change throughout ontogeny are especially rare. Our objectives were to determine how ontogeny influences seedling traits to inform trait selection for future studies and to advance understanding of how traits at early developmental stages influence seedling growth. We measured traits from eleven herbaceous species at several developmental stages. We used Bayesian random effects models to assess the effects and variation resulting from species identity and ontogeny for each trait. We used principal component analysis and multiple regression to identify which dominant axes of variation were correlated with future growth rates. Variation in traits resulting from ontogeny was greatest for growth rates and root elongation rates. Relationships among traits were similar at all ontogenetic stages, but which principal component axes were correlated with future growth depended on stage; at the earliest harvest, the axis related to tissue construction was linked to future growth rate, whereas, at the last harvest, three independent axes were related to future growth rate. In our study, traits including leaf dry matter content, root tissue density, and root diameter varied little throughout seedling development and thus may be promising candidates for future trait-based studies. Linking suites of traits to growth strategies may be particularly fruitful for understanding plant strategies throughout early development, as multivariate relationships among traits appear to be more ontogenetically stable than individual traits.

Identification and characterization of a novel multi-stress responsive gene in Arabidopsis.

Abiotic stresses especially salinity, drought and high temperature result in considerable reduction of crop productivity. In this study, we identified AT4G18280 annotated as a glycine-rich cell wall protein-like (hereafter refer to as GRPL1) protein as a potential multistress-responsive gene. Analysis of public transcriptome data and GUS assay of pGRPL1::GUS showed a strong induction of GRPL1 under drought, salinity and heat stresses. Transgenic plants overexpressing GRPL1-3HA showed significantly higher germination, root elongation and survival rate under salt stress. Moreover, the 35S::GRPL1-3HA transgenic lines also showed higher survival rates under drought and heat stresses. GRPL1 showed similar expression patterns with Abscisic acid (ABA)-pathway genes under different growth and stress conditions, suggesting a possibility that GRPL1 might act in the ABA pathway that is further supported by the inability of ABA-deficient mutant (aba2-1) to induce GRPL1 under drought stress. Taken together, our data presents GRPL1 as a potential multi-stress responsive gene working downstream of ABA.

Effects of salinity, drought and heavy metal stress during seed germination stage in ricebean [Vigna umbellata (Thunb.) Ohwi and Ohashi

Plants are frequently exposed to a variety of stress conditions such as drought, salinity, heavy metal toxicity, low temperature, flooding, extremes of soil pH and heat which causes reduction of plant growth and productivity. Such abiotic stresses may cause metabolic impairment, nutrient imbalance, reduced synthesis of photosynthetic pigments which are closely related with biomass production in plant, thus, causing serious loss in crop productivity. The present experiment was undertaken to study the biochemical and physiological effects of salinity, drought and heavy metal (copper and lead) stress on seed germination in ricebean [Vigna umbellata (Thunb.) Ohwi and Ohashi] variety Bidhan 1. For studying the effect of iso-osmotic potential of salinity and drought stress, the solutions of NaCl and PEG 6000 with − 0.2, − 0.4 and − 0.8 MPa osmotic potential were used whereas the solutions of 50, 100 and 200 µM Cu and Pb supplemented in the form of CuSO4.·5H2O and Pb(NO3)2 respectively were used to study the effects of equimolar concentrations of copper and lead. Drought was found to produce more adverse effects on germination %, as well as speed of germination, in the seeds of ricebean. The seed protein content was significantly higher under all the treatments of salinity, drought stress as well as metal stress. The highest intensity of copper stress was found to produce more adverse effects than lead in respect of water uptake % in germinating seeds and root elongation rates of ricebean seeds in the present experiment. The presence of copper in the germinating medium produced more detrimental effects on activities of antioxidative enzyme ascorbate peroxidase and guaiacol peroxidase than equimolar concentrations of lead.

Subcellular distribution of aluminum associated with differential cell ultra-structure, mineral uptake, and antioxidant enzymes in root of two different Al+3-resistance watermelon cultivars

Crop plants, such as watermelon, suffer from severe Aluminum (Al3+)-toxicity in acidic soils with their primary root elongation being first arrested. However, the significance of apoplastic or symplastic Al3+-toxicity in watermelon root is scarcely reported. In this work, we identified a medium fruit type (ZJ) and a small fruit type (NBT) as Al+3-tolerant and sensitive based on their differential primary root elongation rate respectively, and used them to show the effects of symplastic besides apoplastic Al distribution in the watermelon's root. Although the Al content was higher in the root of NBT than ZJ, Al+3 allocated in their apoplast, vacuole and plastid fractions were not significantly different between the two cultivars. Thus, only a few proportion of Al+3 differentially distributed in the nucleus and mitochondria corresponded to interesting differential morphological and physiological disorders recorded in the root under Al+3-stress. The symplastic amount of Al+3 substantially induced the energy efficient catalase pathway in ZJ, and the energy consuming ascorbate peroxidase pathway in NBT. These findings coincided with obvious starch granule visibility in the root ultra-structure of ZJ than NBT, suggesting a differential energy was used in supporting the root elongation and nutrient uptake for Al+3-tolerance in the two cultivars. This work provides clues that could be further investigated in the identification of genetic components and molecular mechanisms associated with Al+3-tolerance in watermelon.

Distance-to-Time Conversion Using Gompertz Model Reveals Age-Dependent Aerenchyma Formation in Rice Roots.

Distance-to-time conversion by using the Gompertz model compensates for the differences in root elongation rates among different genotypes and conditions, and reveals age-dependent aerenchyma formation.

Pathways to persistence: plant root traits alter carbon accumulation in different soil carbon pools

AimsMineral-associated organic matter, mainly derived from microbial by-products, persists longer in soil compared to particulate organic matter (POM). POM is highly recalcitrant and originates largely from decomposing root and shoot litter. Theory suggests that root traits and growth dynamics should affect carbon (C) accumulation into these different pools, but the specific traits driving this accumulation are not clearly identified.MethodsTwelve herbaceous species were grown for 37 weeks in monocultures. Root elongation rate (RER) was measured throughout the experiment. At the end of the experiment, we determined morphological and chemical root traits, as well as substrate induced respiration (SIR) as a proxy for microbial activity. Carbon was measured in four different soil fractions, following particle-size and density fractionation.ResultsRoot biomass, RER, root diameter, hemicellulose content and SIR (characteristic of N2-fixing Fabaceae species), were all positively correlated with increased C in the coarse silt fraction. Root diameter and hemicellulose content were negatively correlated with C in the POM fraction, that was greater under non N2-fixing Poaceae species, characterized by lignin-rich roots with a high carbon:nitrogen ratio that grew slowly. The accumulation of C in different soil pools was mediated by microbial activity.ConclusionsOur results show that root traits determine C input into different soil pools, mediated primarily by microbial activity, thus determining the fate of soil organic C. We also highlight that C in different soil pools, and not only total soil organic C, should be reported in future studies to better understand its origin, fate and dynamics.

Modelling time variations of root diameter and elongation rate as related to assimilate supply and demand.

In a given root system, individual roots usually exhibit a rather homogeneous tip structure although highly different diameters and growth patterns, and this diversity is of prime importance in the definition of the whole root system architecture and foraging characteristics. In order to represent and predict this diversity, we built a simple and generic model at root tip level combining structural and functional knowledge on root elongation. The tip diameter, reflecting meristem size, is used as a driving variable of elongation. It varies, in response to the fluctuations of photo-assimilate availability, between two limits (minimal and maximal diameter). The elongation rate is assumed to be dependent on the transient value of the diameter. Elongation stops when the tip reaches the minimal diameter. The model could satisfactorily reproduce patterns of root elongation and tip diameter changes observed in various species at different scales. Although continuous, the model could generate divergent root classes as classically observed within populations of lateral roots. This model should help interpret the large plasticity of root elongation patterns which can be obtained in response to different combinations of endogenous and exogenous factors. The parameters could be used in phenotyping the root system.

Least limiting water and matric potential ranges of agricultural soils with calculated physical restriction thresholds

The least limiting water range (LLWR) is a modern and widely used soil physical quality indicator based on predefined limits of water availability, aeration, and penetration resistance, providing a range of soil water contents in which their limitations for plant growth are minimized. However, to set up the upper and lower limits for a range of soil physical properties is a challenge for LLWR computation and hence for adequate water management. Moreover, the usual LLWR is given in terms of the soil water content in which only for field capacity and permanent wilting point, the matric potential range is known. In this paper, we present a procedure for calculating LLWR using Genuchten’s water retention curve parameters and introducing the least limiting matric potential ranges of agricultural soils, which we named LLMPR, defined as the range of matric potential for which soil aeration, water availability, and mechanical resistance would not be restrictive to plant growth. Additionally, we calculated the minimal air-filled porosity, field capacity, permanent wilting point, and limiting soil penetration resistance thresholds which define the upper and lower limits of LLWR and LLMPR. Finally, we present some application examples using experimental data (from cultivated and forest soils) and developed an algorithm for their calculation in the R software. The calculated soil physical restriction thresholds were sensitive to changes in soil structure and clay content and were changeable rather than fixed. Based on experimental data, our calculations with the calculated parameters showed that an increase in LLWR and its corresponding LLMPR could be achieved with improvements in soil structure. Higher water content at field capacity, as well as a larger soil penetration resistance threshold to a given root elongation rate were observed in the structured in comparison to the cultivated soil. The LLWR and LLMPR as presented in this study was computationally implemented as an R function (R software), named llwr_llmpr, and in an interactive web page, both available in the R package soilphysics, version 4.0 or later, available from https://arsilva87.github.io/soilphysics/ or CRAN (http://cran.r-project.org/web/packages/soilphysics/index.html).