Root System Characteristics Research Articles

Visual Modeling of Rice Root Growth Based on B-Spline Curve

As a major food production crop in China, the growth and development of rice is an extremely complex systemic process, and the root system is the main organ for rice to obtain nutrients. Therefore, 3D modeling and visualization of the rice root system can help to further understand its morphology, structure and function, and provide an aid for scientific cultivation of rice and improving rice yield for decision making. In this paper, a mathematical model of the rice root system is established based on the B spline curve combined with the L-system approach, using mathematical knowledge based on the 3D morphological characteristics of the real rice root system. The B-Spline Curve is chosen to simulate this, and the recursive definition of B-Spline Curve and its formula are used to realize the modeling of the rice root system curve. Based on the mathematical method of rice root system integration, the bending effect of rice root system at different periods and different growth positions is realized. Finally, the L-system combined with B-Spline Curve is used to construct a rice root system model and realize the rice root system visualization simulation. The simulated image is closer to the real rice root system image in terms of morphological structure and has a strong sense of realism.

Effects of Different Crop Root Systems on Soil Detachment by Concentrated Flow on the Loess Plateau in China

Soil erosion in sloping cropland is a major water and soil conservation issue in the Loess Plateau region, one of the main areas with sloping cropland in China. However, the effect of crop root systems, a major factor potentially influencing soil and water conservation in cropland, on farmland erosion, remains unclear. In the present study, soil erosion was investigated using indoor runoff scouring experiments with millet, maize, and soybean cover, with a bare surface as the control (CK), on sloping surfaces. Crop root system characteristics, rill initiation time, and erosion law, as well as their interactions, were investigated. Rill initiation time in slopes with all three crops slope were greater than that in the bare slope, indicating that crops could significantly enhance soil anti-scourability. Soil detachment rate decreased under crop cover when compared with bare land, considering the average soil detachment rate was the highest under CK, followed by under maize and soybean, and the least under millet. Slope gradient and unit discharge rate were positively correlated with soil detachment rate. Root length density, root surface area density, and root volume density were negatively correlated with soil detachment rate. Moreover, roots in the 0–1 mm diameter range dominantly influenced soil erosion.

Phytoremediation potential evaluation of three rhubarb species and comparative analysis of their rhizosphere characteristics in a Cd- and Pb-contaminated soil

Screening or breeding exceptional plant species for heavy metal phytoremediation is as important as adopting feasible measures to enhance phytoremediation efficiency, which are largely based on clarifying the mechanisms of heavy metal tolerance and accumulation by plants. In this study, cadmium (Cd) and lead (Pb) tolerance and accumulation characteristics of Rheum officinale, R. palmatum, and R. tanguticum were analysed to assess their phytoremediation potential. The seed germination test indicated that these three rhubarb species could tolerate 10 mg L−1 Cd and 100 mg L−1 Pb. However, when sown in Cd- and Pb-contaminated soil, all three rhubarb species exhibited a relatively high Cd accumulation capacity but a considerably low Pb accumulation capacity according to the bioconcentration factors of Cd (0.42–0.47 in shoots and 0.11–0.15 in roots) and Pb (0.004–0.008 in shoots and 0.007–0.013 in roots). The high Cd translocation factors (3.04–4.24) indicated that these three rhubarb species were suitable for Cd phytoextraction. The changes in rhizospheric physicochemical indices were generally similar among the three rhubarb plants in comparison with those of the unplanted soil. However, differential indicator rhizobacteria were identified for the three rhubarb plants, which may be primarily attributed to their different root system characteristics. These enriched rhizobacteria included many plant growth-promoting bacteria, and several of them were also involved in regulating heavy metal uptake by plants, indicating that three rhubarb species likely recruit differentially beneficial rhizobacteria to maintain plant growth and vitality and to regulate heavy metal uptake in the Cd- and Pb-polluted soil. This study identifies new candidate plant resources for the phytoremediation of Cd-polluted soils and provides novel insights into understanding the interactions among heavy metals, rhizobacteria, and plants.

The Absorption and Distribution Characteristics of Willow Clones to Copper and Its Detoxification Mechanism

Phytoremediation technology is a measure to purify pollutants in soil or water through the absorption, volatilization, root filtration, degradation, and stabilization of plants, and its core is to find plants with large biomass and high enrichment. The wild willow tree found in Tonglushan is a fast-growing Euphorbiaceae plant, which has strong tolerance to the heavy metal copper (Cu) and has the characteristics of developed root system, barren resistance, and high economic value. Taking willow as the research object, this paper studied the composition, copper enrichment sites, morphology, subcellular distribution characteristics and absorption, transportation, and enrichment mechanism of willow root exudates under copper stress through hydroponic and pot experiments. By adding phosphate fertilizers, inducers, and other agronomic control measures, the strengthening technology and mechanism of Cu-contaminated soil phytoremediation were studied. The main research contents and results are as follows: the results of hydroponics and pot experiments show that the willow tree has a certain tolerance to Cu, and Cu mainly accumulates in its roots. Oxalic acid, succinic acid, tartaric acid, citric acid, and malic acid are the main organic acids in willow root exudates. Root exudation activity acidified the rhizosphere soil, increased acid exchangeability, and reducible Cu content, while other forms of Cu content decreased. Root exudates affect the uptake and accumulation of copper by willow trees by altering the bioavailability of copper in soil.

宁夏荒漠草原不同林龄人工柠条林地土壤优先流研究

土壤优先流作为土壤中常见的水分流动方式，会造成土壤水分流失、地下水污染及坡面土体稳定性降低等问题。以位于宁夏盐池县的典型荒漠草原为研究区域，通过土壤水分入渗染色法、CT扫描法、图像处理技术相结合的分析方式，选取人工营造9、14、24、35年的柠条灌丛林地，以空白草地作为对照，探究不同恢复年限人工柠条林土壤优先流特征及其与土壤大孔隙与根系的关系。结果表明：（1）不同林龄柠条林地土壤优先流特征及大孔隙度具有显著差异，表现为随着种植年份的增加，土壤大孔隙度逐渐升高，土壤入渗染色深度随之加深，同时染色面积比随着柠条林林龄的增加而增大。（2）土壤基质流深度表现为随着种植年份的增加而增大，人工柠条林地的土壤优先流程度显著高于草地。（3）随着人工柠条林龄的增加，土壤根系数量增加，而灌丛生长发育过程中的根系活动使得灌丛林地土壤具有更多迂曲度低、连通性强的大孔隙，这些大孔隙是导致土壤水分优先迁移的主要因素。因此，植物根系和土壤大孔隙变化是影响荒漠草原人工柠条恢复过程中土壤水分分布的关键因素，合理配置人工林以改善根系及土壤结构特征，或可有效提高荒漠草原地区的土壤水分利用效率。;Soil preferential flow is a common way of water flow in the soil, which causes soil water loss, groundwater pollution, and reduces slope soil stability. This paper takes a typical desert grassland as the research area in Yanchi County, Ningxia. And we selected artificially constructed shrubland (9, 14, 24, and 35 ages) as the research objects and used blank grassland as the control group, which explored the characteristics of soil preferential flow and its relationship with soil structure by soil water infiltration combining dyeing method, CT scanning method, and image processing technology. The results showed that:(1) there were significant differences in soil preferential flow characteristics and macroporosity. Soil macroporosity gradually and color depth of soil infiltration increased with the increase of planting years. Meanwhile, the ratio of dyeing area increased with the increase of Caragana korshinskii forest age. (2) The depth of soil matrix flow increased with the increase of vegetation planting years, and the soil priority degree of artificial Caragana korshinskii forest was significantly higher than that of grassland. (3) With the increase of the age of Caragana korshinskii plantation, the number of soil roots improved. The root activity in the process of shrub growth and development made the soil to have much lower tortuosity and stronger connectivity macropores, which were the main factors to lead to the preferential migration of soil water. Therefore, the changes of plant roots and soil macropores are the key factors to effect the soil water distribution in the process of artificial Caragana korshinskii restoration in desert steppe. The reasonable allocation of artificial forest plantation could improve soil water use efficiency in desert steppe effectively owing to its role in root system and soil structure characteristics modification.

Caviano: black bean cultivar with large root system and wide adaptability

‘Caviano’ is a black bean cultivar recommended for Santa Catarina, for being highly adaptable to the main grain-producing regions of the state (mean grain yield 2315 kg ha-1). Compared to previously released cultivars, Caviano has a larger root system and desirable characteristics for mechanical harvesting.

Source-sink relationship and yield stability of two maize cultivars in response to water and fertilizer inputs in northwest China

Increasing the capacity of plants to assimilate carbon (source), or to tap into the internal carbon reservoir (sink), has the potential of realizing high and stable yield under a more variable climate. A three-year field experiment was conducted to explore the source-sink relationships of two maize (Zea mays L.) cultivars in response to various water and fertilizer inputs, and evaluate the yield sustainability in northwest China. There were two fertilization rates (unfertilized, F0; fertilized, F1), two irrigation strategies (rainfed, RF; supplemental drip irrigation, DI) and two maize cultivars (ZD958 and QL14). The results showed that the newly released maize cultivar (QL14) had higher leaf chlorophyll content at the silking and grain-filling stages than the old one (ZD958); meanwhile, QL14 had higher root dry matter at maturity than ZD958 under DIF1. The aboveground and root dry matter increased with the amount of water and fertilizer, while the root-shoot ratio decreased. Cultivar significantly affected the vegetative organ dry matter partitioning, especially under severe drought at the silking stage. QL14 had stronger root system and larger leaf dry matter than ZD958, and was more drought-resistant under serious water-stressed conditions. Dry matter translocation (DMT) was crucial for grain yield formation under limited nutrients conditions, and ~55% of total dry matter at maturity was accumulated at the grain-filling stage under adequate water and fertilizer conditions. DIF1 had higher sustainable yield index (SYI) than RFF1. There was no significant difference in grain yield between the two maize cultivars under DIF1, but the average SYI of QL14 (0.94) was greater than that of ZD958 (0.89). The present study indicates that the newly released maize cultivar (QL14) with stronger root system and stay-green characteristics is beneficial for increasing drought resistance and keeping yield stable in the semi-humid and drought-prone region of northwest China.

Biochar increases tobacco yield by promoting root growth based on a three-year field application

In order to explore the effects of biochar on root system and growth characteristics of flue-tobacco, three years of field experiments were conducted to study the influence of different biochar application levels [600 (T1), 1200 (T2), 1800(T3), 2400 (T4), 3000 (T5) kg/ha] and no fertilizer (CK) on the root physiological indexes and growth index of tobacco. Compared with local conventional fertilization, the application rate of N fertilizer in each treatment (except for control) was reduced by 40% to analyze the effects of different amount of biochar on the physiological indexes of tobacco roots and leaf photosynthesis during flourishing. The results showed that tobacco plants' root development status in the flourishing period was consistent with the photosynthetic physiological indexes, chlorophyll content, and leaf-area coefficient. Compared with the control, the application of biochar could increase the root vigor by 177.8%. Biochar improved the roots, increasing the total root area by 91.35% and the number of root tips by 100.9%. Meanwhile, biochar increased the net photosynthetic rate of tobacco leaves by 77.3% and the total tobacco biomass by 72.5%. Studies have shown that biochar can promote the development of tobacco roots, and then enhance the photosynthesis of leaves, so that tobacco plants can grow healthily, which is conducive to the tobacco production and the cultivation of soil.

Root system characteristics under different water regimes in three cereal species

Root system characteristics under different water regimes in three cereal species

Root-Plate Characteristics of Common Aspen in Hemiboreal Forests of Latvia: A Case Study

Climate change will cause winds to strengthen and storms to become more frequent in Northern Europe. Windstorms reduce the financial value of forests by bending, breaking, or uprooting trees, and wind-thrown trees cause additional economic losses. The resistance of trees to wind damage depends on tree species, tree- and stand-scale parameters, and root-soil plate characteristics such as root-plate size, weight, and rooting depth. The root-soil plate is a complex structure whose mechanical strength is dependent on root-plate width and depth, as the root system provides root attachment with soil and structural support. In Latvia, the common aspen (Populus tremula L.) root system has been studied to develop a belowground biomass model, because information about root system characteristics in relation to tree wind resistance is scarce. The aim of this study was to assess the root-plate dimensions of common aspen stands on fertile mineral soil (luvisol). Study material was collected in the central region of Latvia, where pure mature (41–60 years old) common aspen stands were randomly selected, and dominant trees within the stand were chosen. In total, ten sample trees from ten stands were uprooted. The diameter at breast height (DBH) and tree height (H) were measured for each sample tree, and their roots were excavated, divided into groups, washed, measured, and weighed. The highest naturally moist biomass values were observed for coarse roots, and fine root biomass was significantly lower compared to other root groups. All root group biomass values had a strong correlation with the tree DBH. The obtained results show that there is a close, negative relationship between the relative distance from the stem and the relative root-plate depth distribution.

Relationship between Very Fine Root Distribution and Soil Water Content in Pre- and Post-Harvest Areas of Two Coniferous Tree Species

Tree root system development alters forest soil properties, and differences in root diameter frequency and root length per soil volume reflect differences in root system function. In this study, the relationship between vertical distribution of very fine root and soil water content was investigated in intact tree and cut tree areas. The vertical distribution of root density with different diameter classes (very fine <0.5 mm and fine 0.5–2.0 mm) and soil water content were examined along a slope with two coniferous tree species, Cryptomeria japonica (L.f.) D. Don and Chamaecyparis obtusa (Siebold et Zucc.) Endl. The root biomass and length density of very fine roots at soil depth of 0–5 cm were higher in the Ch. obtusa intact tree plot than in the Cr. japonica intact plot. Tree cutting caused a reduction in the biomass and length of very fine roots at 0–5 cm soil depth, and an increment in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot one year after cutting. However, very fine root density of the Cr. japonica intact tree plot was quite low and the soil water content in post-harvest areas did not change. The increase in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot could be caused by the decrease in very fine roots at 0–5 cm soil depth. These results suggest that the distribution of soil water content was changed after tree cutting of Ch. obtusa by the channels generated by the decay of very fine roots. It was also shown that differences in root system characteristics among different tree species affect soil water properties after cutting.

Effects of Straw and Biochar Amendments on Grassland Productivity and Root Morphology

The objective of this research was to determine the effect of straw and biochar amendment on the root system morphology and aboveground biomass of a red clover/grass mixture (Lolium. perenne L., Phleum pratense L., Festuca pratensis Huds., F. arundinacea Schreb., L. multiflorum L., L. westerwoldicum Breakw., Trifolium pratense L.). A grassland experiment was conducted from 2014 to 2018. Straw was collected from miscanthus (Miscanthus × giganteus), winter wheat (Triticum aestivum L.), and biochar was produced from the biomass of those species. The following treatments were applied: wheat straw at a rate of 5 t ha−1 (WS), miscanthus straw at a rate of 5 t ha−1 (MS), wheat biochar at a rate of 5 t ha−1 (WBH), wheat biochar at a rate of 2.25 t ha−1 (WBL), miscanthus biochar at a rate of 5 t ha−1 (MBH), and miscanthus biochar at a rate of 2.25 t ha−1 (MBL). A treatment with mineral fertilizer but without organic amendments (MCTR) was used, and a control treatment (CTR) without mineral fertilizer and without any amendments was also tested. The botanical composition and the aboveground yields were determined. The roots were sampled in 2018, and the root morphology parameters were determined using an image analysis system. The applied soil amendments resulted in increased root lengths, surface areas, volumes, and mean root diameters. There were no differences between the treatments with different feedstock types (miscanthus vs. wheat), materials (straw vs. biochar), or amendment rates (5 vs. 2.25 t ha−1). The resulting root system characteristics were reflected in the aboveground biomass productivity. The soil amendments, i.e., the straw and biochar, significantly increased the productivity in comparison to that of the control treatment. However, these differences were noticed only during the first and second cuts. Recommended practice in grassland management is to improve soil with straw. The conversion of straw into biochar does not provide a better effect on grassland productivity.

Carbon and Nitrogen Stocks and Soil Quality in an Area Cultivated with Guinea Grass under the Residual Effect of Nitrogen Doses

This study examines the residual effect of nitrogen (N) doses on the carbon (C) and N stocks and on soil quality in an area cultivated with guinea grass. The pastures received three annual doses of N (100, 200 and 300 kg ha−1) from 2015 to 2017. In 2018, N fertilization was not applied so the residual effect of the nutrient could be characterized. Soil chemical attributes, C and N stocks, density and penetration resistance and root system characteristics were evaluated at different depths. No difference was observed between the N doses for soil density, which averaged 1.22 and 1.25 g cm−3 under and between the tussocks of guinea grass, respectively. Penetration resistance was affected by the N doses post-grazing, with the highest value (1.9 MPa) observed in pastures that received 300 kg ha−1 of N for three consecutive years. Root dry mass was not affected by the N doses. There was no effect of N doses on the average (19.7 mg ha−1) or total (134.3 mg ha−1) C stock in the soil. The total N stock did not change (11.3 mg ha−1) in response to the N doses; however, the average N stock was higher in the soil cultivated with guinea grass under the N dose of 300 kg ha−1 (1.7 mg ha−1). The N doses had little interference with the soil chemical and physical aspects. Regardless of the dose, high C and N stocks were observed in the soil cultivated with guinea grass. Therefore, when properly managed, intensive pasture-based animal production systems become important allies of the environment.

Rootstocks and planting types on root architecture and vegetative vigor of ‘Pera’ sweet orange trees

ABSTRACT Root architecture affects plant growth and agricultural productions. Although it is related to genetic factors, soil physical limitations can affect the root system and volume of explored soil, compromising plant growth and fruit production. Considering the need to mitigate these restrictions, the objective of the present study was to evaluate two planting types (planting of protected seedlings and planting of seeds in definitive place) and two scion-rootstock combinations (‘Pera’ sweet orange, CNPMF D-6 selection, combined with ‘Santa Cruz Rangpur’ lime and ‘Sunki Tropical’ mandarin rootstocks). The experiment was conducted at the Lagoa do Coco Farm, Rio Real, BA, Brazil, in a Oxisol under rainfed conditions. Biometric, physiological, and soil water content evaluations were made during the experiment. Soil mechanical resistance to root penetration and root system characteristics were also evaluated. Roots were concentrated on the soil surface layers (0-0.40 m), extending horizontally up to 1.50 m from the plant, regardless of the management practices used. The total root length in each root diameter classes studied, root length density, and total root mean diameter were higher for planting of protected seedling, resulting in greater root development. Plants from ‘Pera’ sweet orange scion grafted on ‘Santa Cruz Rangpur’ lime rootstock had earlier production and were more vigorous. Soil structure affects root growth, and the root distribution up to 0.40 m depth is correlated with plant vigor, yield, and water status under rainfed conditions.

Seedling root characteristics and drought resistance of wheat in Shanxi province

<p indent=0mm>Wheat root morphology at the seedling stage is the basis of root distribution at the adult stage. It is closely related to stress resistance and yield. A comprehensive understanding of the root system characteristics at seedling stage and drought resistance is of great significance for the excellent germplasm utilization and early screening of drought resistance. Using 239 wheat varieties (lines) from Shanxi province, the root traits at seedling stage and their response to water stress were evaluated. The results showed that under normal growth, Shanxi wheat had a great variation in root traits at seedling stage, with the greatest variation in landraces. The maximum root length (MRL) tended to decrease slightly with the years, while other root traits were first increased and then decreased. There were differences among the root traits in response to water stress. The total root length (TRL) is the most sensitive to water, followed by root surface area (RSA), root volume (RV) and root biomass. The maximum root length (MRL) and the average number of roots (RN) were insensitive. The drought resistance of seedling roots showed a trend of decreasing first and then increasing with the years. Landraces and varieties released from 1970 to 1979 had moderately resistance to water stress, varieties released from 1980 to 1999 had lower drought resistance, and varieties released after 2000 had the better resistance, of which the dryland varieties were the best resistance. Correlation analysis of the seedling root characteristics and yield related traits suggested that the maximum root length, total root length, root volume and root biomass were significantly positively correlated with 1000-kernel weight and yield under rain-fed conditions, and the maximum root length and root biomass were also significantly positively correlated with adult plant drought resistance. The present study suggests that the maximum root length and root biomass at the seedling stage can be used as early generation selection parameters for drought resistance and yield in dryland breeding in semi-arid areas.

A functional-structural model of upland rice root systems reveals the importance of laterals and growing root tips for phosphate uptake from wet and dry soils.

Upland rice is often grown where water and phosphorus (P) are limited. To better understand the interaction between water and P availability, functional-structural models that mechanistically represent small-scale nutrient gradients and water dynamics in the rhizosphere are needed. Rice was grown in large columns using a P-deficient soil at three P supplies in the topsoil (deficient, sub-optimal and non-limiting) in combination with two water regimes (field capacity vs. drying periods). Root system characteristics, such as nodal root number, lateral types, interbranch distance, root diameters and the distribution of biomass with depth, as well as water and P uptake, were measured. Based on the observed root data, 3-D root systems were reconstructed by calibrating the structural architecure model CRootBox for each scenario. Water flow and P transport in the soil to each of the individual root segments of the generated 3-D root architectures were simulated using a multiscale flow and transport model. Total water and P uptake were then computed by adding up the uptake by all the root segments. Measurements showed that root architecture was significantly affected by the treatments. The moist, high P scenario had 2.8 times the root mass, double the number of nodal roots and more S-type laterals than the dry, low P scenario. Likewise, measured plant P uptake increased >3-fold by increasing P and water supply. However, drying periods reduced P uptake at high but not at low P supply. Simulation results adequately predicted P uptake in all scenarios when the Michaelis-Menten constant (Km) was corrected for diffusion limitation. They showed that the key drivers for P uptake are the different types of laterals (i.e. S- and L-type) and growing root tips. The L-type laterals become more important for overall water and P uptake than the S-type laterals in the dry scenarios. This is true across all the P treatments, but the effect is more pronounced as the P availability decreases. This functional-structural model can predict the function of specific rice roots in terms of P and water uptake under different P and water supplies, when the structure of the root system is known. A future challenge is to predict how the structure root systems responds to nutrient and water availability.

Physiological responses of lettuce (Lactuca sativa L.) to microplastic pollution.

Concerns about the pollution of farmlands by microplastics and the associated toxicology have increased in recent times; however, studies on this topic are scarce. In this study, two kinds of PVC microplastics with different particle sizes (PVC-a with particle sizes from 100nm to 18μm, and PVC-b with particle sizes from 18 to 150μm) and different content levels (0.5%, 1%, and 2%) were used to analyze the effects of PVC microplastics on the physiological characteristics of the lettuce root system and leaves. The results showed that PVC-a and PVC-b had no significant effect on the lettuce root activity. However, 0.5%a and 1%a significantly increased the total length, surface area, volume, and diameter of roots. In terms of leaves, PVC-a and PVC-b had no significant effect on the malondialdehyde content, but 1%a significantly increased the superoxide dismutase activity. Carotenoid synthesis was promoted by PVC-a but inhibited by PVC-b. Furthermore, 1%a could reduce the ability of light energy absorption, dissipation, capture, and electron transfer. The gray correlation analysis indicated that PVC-a correlated to a considerable degree with the indices related to photosynthesis, while PVC-b was significantly correlated with the indices related to root morphology. This study provides insights into the ecotoxicological effect of microplastics on farmland crops and associated ecological risk assessment.

The effects of tree root density on water infiltration in urban soil based on a Ground Penetrating Radar in Shanghai, China

Urbanization often leads to soil compaction and reduces soil water infiltration rates which then increase runoff and flooding. Comparison of infiltration rates associated with tree root systems with different root distributions can help establish predictive models and improve species selection to mitigate runoff and flooding in urban environments. In Shanghai, 90 trees of 10 different species were scanned using a Ground Penetrating Radar. Soil properties were measured as well as the characteristics of the tree root systems, and their effects on infiltration were analyzed. Compared to the turf, tree roots increased the initial infiltration rate (53–330 %) and steady infiltration rate (89–2167 %). Trees with deep root distributions improved infiltration the most, followed by medium and shallow root distributions. Soil porosity and bulk density, the two most important factors that affect soil infiltration below 15 cm, became increasingly unfavorable to infiltration as the soil depth increased, which could be counterbalanced by the root systems. Relationship models of roots and soil infiltration in different soil layers were established to rapidly predict the infiltration of different tree species. Mixed planting of trees with different root distribution characteristics should be popularized, to ensure root systems develop at different soil depths, thus optimizing the infiltration effects of urban trees.

A lightweight bionic design for a scanner based on the 3D architecture of root system of pine trees

Lightweight design is usually a critical criterion in many engineering fields. In addition to the well-developed method topology optimization, structural bionics is also considered an effective approach to obtain innovative designs with lightweight. In nature, trees have evolved highly developed root systems to maximize the efficiency in anchorage. Inspired by the 3D branch structure of plant roots, this paper selects the root system of pine trees as a biological prototype for the optimization of a scanner which has a strict requirement for the flatness. First, a topology-optimized structure of the scanner is modeled and simulated for its mechanical behavior. Next, architectural and mechanical characteristics of the tap root system of pine trees are investigated through sensitivity analysis. Similarity analysis between the root system and the scanner is performed from three aspects. Then, by imitating the spatial configuration of pine tree roots, a bionic design for the scanner is proposed and modeled. Finally, finite element method (FEM) is carried out to evaluate the mechanical performance of the original model, the bionic model, and the topology-optimized model in terms of weight, dynamics response, and specific stiffness efficiency. Comparison results show that the proposed bionic model provides the best lightweight solution for the scanner, followed by the topology-optimized model. The proposed bionic model suggests a new solution to the design of the supporting system of “tower-like” structures and extends the application of branch-based bionics from planar systems to complex spatial systems.

Research on the Construction and Visualization of a Three-Dimensional Model of Rice Root Growth

HighlightsThis article proposes a three-dimensional rice root growth model based on the differential L-system.We tested the accuracy of the model output, and the measured values and the simulated values were compared.A three-dimensional visualization of the growth simulation system was implemented, and the dynamic growth process of rice roots was visually reproduced.Abstract. Three-dimensional visualization studies on the morphological characteristics of rice root systems are important for improving farmland management and for the selective breeding and genetic improvement of rice. To clarify the rules governing the structure and distribution of rice roots, the three-dimensional (3D) coordinates and morphological parameters of rice roots were measured in hydroponic experiments at different growing periods, and the rice root structure was measured with a high degree of accuracy. The initial position, growth direction, and rate were then determined via statistical analysis of the data. In this article, a 3D rice root growth model based on the differential L-system is proposed; in this system, the biological characteristics based on the topological structure and the actual growth laws of rice roots are quantified. We adopted the growing degree day (GDD) as the driving factor that describes the growth law of rice roots and tested the accuracy of the model output. In this model, a 3D visualization of the growth simulation system of rice roots is implemented via Visual C++ and the OpenGL standard library on the basis of algorithms for the constructed 3D rice root growth model. The model output realistically recreates the dynamic growth process of rice roots under different conditions. A large amount of experimental data and comparative analysis show that the average accuracies achieved by the proposed system concerning total root length, root surface area and root volume are 96.95%, 95.97%, and 93.98%, respectively. These results verify the high reliability of the constructed model and the effective simulation of the morphological characteristics and growth laws of rice roots at different growth periods, laying the foundation for future research on the laws of changes in morphological structure and the physiological and ecological factors of rice roots at different growth stages. Keywords: Differential L-system, Rice roots, Simulation, Three-dimensional growth model, Visualization.