Deep Root Research Articles

Three new species of Jainus (Monogenoidea: Dactylogyridae) from the gills of Triportheus angulatus (Characiformes: Triportheidae) collected in the Peruvian Amazonia.

Three new species of Jainus Mizelle, Kritzky & Crane, 1968, are described parasitizing the gill filaments of Triportheus angulatus (Spix & Agassiz) (Characiformes: Triportheidae), an omnivorous fish endemic to the Amazon River basin. Jainus iquitensis n. sp. is characterized by the morphology of the vagina, which is bell-shaped, with a canal as a sclerotized tube and the morphology of hook pair VII, which in the new species presents an inflated base, a characteristic not observed in other congeners. Jainus loretoensis n. sp. is unique among Jainus species due to the morphology of its Y-shaped ventral anchors, with an arrow-shaped superficial root and a finger-shaped deep root. Jainus sardinae n. sp. is characterized by presenting a slender, small J-shaped tube with a sigmoid accessory piece and a ventral anchor that is Y-shaped, with inconspicuous finger-shaped deep root and superficial root with rounded ending with a chin-shaped projection. These findings add three new species to the previously reported two Jainus species from Peru.

A Comprehensive Review of Nano-sized Silica’s Effects on Plant Growth, Molecular Responses, and Biochemical Changes

Silicon (Si) is a tetravalent metalloid and second most abundant on earth approximately 28%. Slags were used in agriculture as a silica fertilizer (10–28% Si); which improvise degraded crop soils, as well as crop growth and disease resistance. Si improves abiotic stress in crop lodging, UV tolerance, improves water uptakes and blocking the NaCl toxicity was observed in Gramineae family. It showed tolerance to biotic stress in terms of physical strengthening of plants against microbial infestation and activation of defensive enzymes such as peroxidase, polyphenol oxidase, lipoxygenase, phenylalanine ammonia lyase. There was an enhanced vegetative growth and germination percentage in varied vegetable crops with 100 to 500ppm range of silica nanoparticles. The plants available Si (H4SiO4) form in soil solution ranges about 0.1 to 0.6 mM and it get absorbed from roots via xylem to shoot containing a specialized cell surface protein called as Nod26-like major intrinsic protein (NIP) of aquaporin family. The list of total genes responsible for uptake of silica form are Low silica genes (Lsi1, Lsi2, Lsi3, Lsi6) and Si efflux transporter genes (SIET3, SIET4, SIET5). The nano-sized silica have been proven to be more validated impact on genes responsiveness via morpho-physiological parameter relationship. It is concluding that, use of silica in commercial crops have deep root to influence the genes and a bright future in its crop growth development aspects.

Research on the Marketization Development of Traditional Chinese Culture

Traditional culture usually has a long history and deep root, and it represents the spiritual symbols and cultural characteristics of a country or region. As China's economy continues to develop, the status and role of traditional culture in Chinese society has attracted much attention. The marketisation of Chinese traditional culture has also become an important issue in China today. This thesis aims to explore the current situation, real cases and challenges of the development of Chinese traditional culture in the process of marketisation. The challenges of the marketisation of traditional culture are explored through case studies on the development, inheritance and integration of traditional culture with modern business models under the conditions of market economy. It is found that the popularity of traditional cultural products in the market has gradually increased and the chain of cultural industry has become increasingly complete. At the same time, people of different generations have different degrees of acceptance of traditional cultural industries, and inheritance and development are facing dramatic collisions. This study concludes that Chinese traditional culture faces both opportunities and challenges in the process of market-oriented development. Chinese people should grasp the balance between inheritance and innovation, and use the power of the new era to promote the treasures left behind by their forefathers.

Disability as a Resource

Chinese modern writer Shi Tiesheng’s renowned piece of life writing “The Temple of Earth and I” embodies a conceptualization of disability that underscores the positive potential of disability as resource that may bring power, freedom, and diversity to people with disabilities as well as the entire society. The representation of disability in Shi’s writing forms an alternative disability discourse that can be highly valuable in shaping social and cultural mindsets on disability. Shi’s disability discourse takes a deep root in Chinese philosophical tradition that understands the world as a dynamic process of transformation between oppositional states. In accordance with this recognition, disability has the potential to be transformed from loss to power, from limitation to freedom, and from an often rejected and excluded element to an indispensable part of diversity in the world.

Bioenergy sorghum nodal root bud development: morphometric, transcriptomic and gene regulatory network analysis.

Bioenergy sorghum's large and deep nodal root system and associated microbiome enables uptake of water and nutrients from and deposition of soil organic carbon into soil profiles, key contributors to the crop's resilience and sustainability. The goal of this study was to increase our understanding of bioenergy sorghum nodal root bud development. Sorghum nodal root bud initiation was first observed on the stem node of the 7th phytomer below the shoot apex. Buds were initiated near the upper end of the stem node pulvinus on the side of the stem opposite the tiller bud, then additional buds were added over the next 6-8 days forming a ring of 10-15 nascent nodal root buds around the stem. Later in plant development, a second ring of nodal root buds began forming on the 17th stem node immediately above the first ring of buds. Overall, nodal root bud development can take ~40 days from initiation to onset of nodal root outgrowth. Nodal root buds were initiated in close association with vascular bundles in the rind of the pulvinus. Stem tissue forming nascent nodal root buds expressed sorghum homologs of genes associated with root initiation (WOX4), auxin transport (LAX2, PIN4), meristem activation (NGAL2), and genes involved in cell proliferation. Expression of WOX11 and WOX5, genes involved in root stem niche formation, increased early in nodal root bud development followed by genes encoding PLTs, LBDs (LBD29), LRP1, SMB, RGF1 and root cap LEAs later in development. A nodal root bud gene regulatory network module expressed during nodal root bud initiation predicted connections linking PFA5, SPL9 and WOX4 to genes involved in hormone signaling, meristem activation, and cell proliferation. A network module expressed later in development predicted connections among SOMBRERO, a gene involved in root cap formation, and GATA19, BBM, LBD29 and RITF1/RGF1 signaling. Overall, this study provides a detailed description of bioenergy sorghum nodal root bud development and transcriptome information useful for understanding the regulation of sorghum nodal root bud formation and development.

Deep Rooting as an Indicator of Deep Soil Water and N Uptake in Potato (Solanum tuberosum L.)

AbstractBreeding for potato deep roots can increase water and nitrogen uptake by potatoes and it can be an option to maintain stable yields with decreased inputs. This study investigates the relationship between potato root characteristics, water stress resistance and deep soil nitrogen uptake, accessing variations among cultivars and nitrogen fertilization levels. Thirteen potato cultivars were grown during 2018 and 2020 at a semi-field root phenotyping platform in Denmark. Root growth was monitored via minirhizotron tubes down to 1.8 m soil depth. Drought treatment started in the mid-June and deep soil nitrogen uptake was tracked via 15N isotope application at 1.3–1.4 m soil depth during tuber formation. Water stress resilience was identified using 13C natural discrimination process in plants. Tuber samples were analyzed for 15N and 13C content. While drought affected potato yield (not always significantly), it did not affect nitrogen uptake. Root length and distribution varied among varieties, with deeper roots (down to 1.30 m) observed in August. Statistical differences (p < 0.05) in root length, yield and nitrogen uptake were found among varieties. Cultivars with longer growing season exhibited larger, deeper roots and increased nitrogen uptake from deep soil. High correlation (R = 0.8) between deep roots and 15N uptake was observed for all varieties. Deeper roots are contributing to deep soil nitrogen uptake, but 13C content in tubers is not a reliable indicator of water stress resilience. Despite this, the study suggests the potential for breeding potatoes with deep roots to achieve stable yields, considering differences in water and nitrogen uptake among varieties.

Persistent biogeochemical signals of land use-driven, deep root losses illuminated by C and O isotopes of soil CO2 and O2

Persistent biogeochemical signals of land use-driven, deep root losses illuminated by C and O isotopes of soil CO2 and O2

A Study on the Key Factors for the Sustainable Development of Shared Mobility Based on TDM Theory: The Case Study from China

This study is based on an investigation of shared mobility in Chinese cities, which identifies the factors affecting the sustainable development of shared mobility based on the theoretical framework of TDM (travel demand management). Through a literature review and expert interviews, the FUZZY-DEMATEL-ISM-MICMAC integration model was used to screen 21 influencing factors from aspects that fit the research theme. Triangular fuzzy numbers are used to quantify the subjective scores of nine expert groups and weaken the subjective influence of expert scores. The logical relationships among DEMATEL technology-building factors and ISM technology-based factors are divided into levels. The MICMAC technique is used to divide the types of factors according to the driving power and dependency. The results show that (1) the influence factors of the “soft strategy” and “hard strategy” in the framework of TDM are determined. In the soft strategy, we should focus on “shared mobility education” (shared mobility education, shared mobility publicity and shared mobility “environment” information) and “community organization” (community organization and advocacy and organizational interaction). In the hard strategy, we should focus on “traffic planning and measures”, “dedicated lanes”, “parking facilities”, and “financial subsidies”. (2) The ISM recursive structure model is divided into five layers. Among them, shared mobility education, shared mobility operating technology, and organizational interaction are at the deep root level, which can continuously influence other factors in the long run. (3) In MICMAC, the number of related factors is large. When making decisions on these factors, managers should comprehensively consider the correlation of factors and adjust the use of factors from an overall perspective. This study can help managers identify the key factors affecting the sustainability of shared mobility and make targeted recommendations.

Stomatal and Non-Stomatal Leaf Responses during Two Sequential Water Stress Cycles in Young Coffea canephora Plants

Understanding the dynamics of physiological changes involved in the acclimation responses of plants after their exposure to repeated cycles of water stress is crucial to selecting resilient genotypes for regions with recurrent drought episodes. Under such background, we tried to respond to questions as: (1) Are there differences in the stomatal-related and non-stomatal responses during water stress cycles in different clones of Coffea canephora Pierre ex A. Froehner? (2) Do these C. canephora clones show a different response in each of the two sequential water stress events? (3) Is one previous drought stress event sufficient to induce a kind of “memory” in C. canephora? Seven-month-old plants of two clones (’3V’ and ‘A1’, previously characterized as deeper and lesser deep root growth, respectively) were maintained well-watered (WW) or fully withholding the irrigation, inducing soil water stress (WS) until the soil matric water potential (Ψmsoil) reached ≅ −0.5 MPa (−500 kPa) at a soil depth of 500 mm. Two sequential drought events (drought-1 and drought-2) attained this Ψmsoil after 19 days and were followed by soil rewatering until a complete recovery of leaf net CO2 assimilation rate (Anet) during the recovery-1 and recovery-2 events. The leaf gas exchange, chlorophyll a fluorescence, and leaf reflectance parameters were measured in six-day frequency, while the leaf anatomy was examined only at the end of the second drought cycle. In both drought events, the WS plants showed reduction in stomatal conductance and leaf transpiration. The reduction in internal CO2 diffusion was observed in the second drought cycle, expressed by increased thickness of spongy parenchyma in both clones. Those stomatal and anatomical traits impacted decreasing the Anet in both drought events. The ‘3V’ was less influenced by water stress than the ‘A1’ genotype in Anet, effective quantum yield in PSII photochemistry, photochemical quenching, linear electron transport rate, and photochemical reflectance index during the drought-1, but during the drought-2 event such an advantage disappeared. Such physiological genotype differences were supported by the medium xylem vessel area diminished only in ‘3V’ under WS. In both drought cycles, the recovery of all observed stomatal and non-stomatal responses was usually complete after 12 days of rewatering. The absence of photochemical impacts, namely in the maximum quantum yield of primary photochemical reactions, photosynthetic performance index, and density of reaction centers capable of QA reduction during the drought-2 event, might result from an acclimation response of the clones to WS. In the second drought cycle, the plants showed some improved responses to stress, suggesting “memory” effects as drought acclimation at a recurrent drought.

Identifying the ‘deep roots’ of economic freedom with implications for policy and economic reform

Because of the importance of economic freedom for a country’s prosperity and growth, subsequent studies now try to uncover which factors explain the cross-country differences in economic freedom. Based upon Lawson, Murphy, and Powell’s (2020) recent literature review we provide the first empirical examination of the relative importance of all 18 of the key “deep root” factors they identify across the published literature. We employ a Bayesian Model Averaging (BMA) approach that is ideally suited for model identification and provides a statistical means to rank the importance of these deep root factors. Our results suggest that (in order of importance) latitude, exitability as measured by a country’s shape and coastal access, genetic distance, religion, and French legal origins are the most important of the deep root determinants of economic freedom. Policy implications of our findings are also discussed.

Compost incorporation and wildflowers introduction for stormwater infiltration and erosion-control vegetation cover establishment in post-construction landscapes

Urban and suburban development frequently disturbs and compacts soils, reducing infiltration rates and fertility, posing challenges for post-development vegetation establishment, and contributing to soil erosion. This study investigated the effectiveness of compost incorporation in enhancing stormwater infiltration and vegetation establishment in urban landscapes. Experimental treatments comprised a split-split plot design of vegetation mix (grass, wildflowers, and grass-wildflowers) as main plot, ground cover (hydro-mulch and excelsior) as subplot, and compost (30% Compost and No-Compost) as sub-subplot factors. Wildflower inclusion was motivated by their recognized ecological benefits, including aesthetics, pollinator habitat, and deep root systems. Vegetation cover was assessed using RGB (Red-Green-Blue) imagery and ArcGIS-based supervised image classification. Over a 24-month period, bulk density, infiltration rate, soil penetration resistance, vegetation cover, and root mass density were assessed. Results highlighted that Compost treatments consistently reduced bulk density by 19–24%, lowered soil penetration resistance to under 2 MPa at both field-capacity and water-stressed conditions, and increased infiltration rate by 2–3 times compared to No-Compost treatments. Vegetation cover assessment revealed rapid establishment with 30% compost and 60:40 grass-wildflower mix, persisting for an initial 12 months. Subsequently, all treatments exhibited similar vegetation coverage from 13 to 24 months, reaching 95–100% cover. Compost treatments had significantly higher root mass density within the top 15 cm than No-Compost, but compost addition did not alter the root profile beyond the 15 cm depth incorporation depth. The findings suggest that incorporating 30% compost and including a wildflower or grass-wildflower mix appears to be effective in enhancing stormwater infiltration and provides rapid erosion control vegetation cover establishment in post-construction landscapes.

Improving complex agronomic and domestication traits in the perennial grain crop intermediate wheatgrass with genetic mapping and genomic prediction.

The perennial grass Thinopyrum intermedium (intermediate wheatgrass [IWG]) is being domesticated as a food crop. With a deep root system and high biomass, IWG can help reduce soil and water erosion and limit nutrient runoff. As a novel grain crop undergoing domestication, IWG lags in yield, seed size, and other agronomic traits compared to annual grains. Better characterization of trait variation and identification of genetic markers associated with loci controlling the traits could help in further improving this crop. The University of Minnesota's Cycle 5 IWG breeding population of 595 spaced plants was evaluated at two locations in 2021 and 2022 for agronomic traits plant height, grain yield, and spike weight, and domestication traits shatter resistance, free grain threshing, and seed size. Pairwise trait correlations were weak to moderate with the highest correlation observed between seed size and height (0.41). Broad-sense trait heritabilities were high (0.68-0.77) except for spike weight (0.49) and yield (0.44). Association mapping using 24,284 genome-wide single nucleotide polymorphism markers identified 30 main quantitative trait loci (QTLs) across all environments and 32 QTL-by-environment interactions (QTE) at each environment. The genomic prediction model significantly improved predictions when parents were used in the training set and significant QTLs and QTEs used as covariates. Seed size was the best predicted trait with model predictive ability (r) of 0.72; yield was predicted moderately well (r=0.45). We expect this discovery of significant genomic loci and mostly high trait predictions from genomic prediction models to help improve future IWG breeding populations.

Trees in cooler regions are more vulnerable to thermal stress: Evidence from temperate poplar plantations in Northern China during the 2022 heatwaves

Climate change is resulting in more intense and frequent heatwaves, posing a potential threat to the structure and function of forest biome. However, due to the lack of in-situ data, the responses of forest plantations to heatwaves and the role of growth environments and management practices in mitigating these effects remain poorly understood. To address these knowledge gaps, we took advantage of the 2022 summer heatwave to assess their impacts on 8-year-old poplar plantations in Northern China characterized by differing thermal environments (cooler vs. warmer). Stem daily radial increment and sap flow density were continuously monitored in two regions. Additionally, physiological traits, such as leaf gas exchange and water potential, were measured in the warmer region with two different irrigation treatments. Our results revealed that poplar trees in the cooler region experienced more pronounced negative effects from heatwaves compared to those in the warmer region. Poplar trees exhibited strong physiological plasticity to cope with heatwave stress, with increased sap flow density observed in both regions during heatwaves, facilitating a transpiration-cooling effect for minimizing thermal damage. However, increased transpiration rate also led to stored stem water depletion and higher tree water deficit. The ability of trees to regulate internal water balance, likely dependent on their root water supply capacity, accounted for the different responses of poplar growth to heatwaves in various regions. Unexpectedly, while irrigation assisted the functioning of poplar trees in some aspects, it did not alter their overall growth and physiological performance under heatwave conditions, possibly due to their deep root systems. Overall, growth environment temperatures and physiological plasticity are crucial factors affecting the ability to withstand thermal stress, and these variations will allow trees to persist in fluctuating environments. Our findings offer valuable insights for sustainable forest management under extreme climate conditions.

Gravity and magnetic geophysical surveys for exploration of low sulphidation epithermal mining project. Marifil Complex, Chon Aike Igneous Province, Argentina

The Marifil Complex constitutes the early stage of the Chon Aike Igneous Province along eastern North Patagonia, Argentina. Geological, geochronological, and geochemical data indicate that this magmatism consists of two characteristic Lower Jurassic volcanic events (V0 and V1). The epithermal activity takes place in V1 as Au-Ag veins (Pavón Pivetta et al., 2024). Particularly, base metal veins are covered and masked by the important explosive volcanic activity related to the V1 volcanic stage. This makes geophysical exploration a highly recommended tool for interpreting subsurface geological features.With this in mind, we have carried out the acquisition and processing of gravity and magnetic data that is supported with drill holes and geochronological data. A series of gravity and magnetic highs and lows were recognized, together with major lineaments. Using Euler deconvolution, the depth of the sources that generate the anomalies was calculated. The analysis of these results allowed us to construct two perpendicular gravity 2D models for the calculation of thicknesses and depth of the rhyolitic coulée. The gravity lows were associated with the major thickness of rhyolitic coulée, reaching 290 m in the drill holes, and interpreted geophysically to have a deeper root. The gravity highs were interpreted in two possible ways: a basement depth decrease and/or the absence of the rhyolitic coulée. The minimum depth estimated for the basement highs is approximately 20 m. These interpretations are consistent with outcrop, drill hole and geochronologic data, and magnetic maps. The RMSE between the calculated and the observed anomalies of the models are about 0.316 and 0.519 mGal. Due to the shape of the anomalies obtained from the gravimetric maps, the structures that generate the anomalies were considered as generated by three-dimensional bodies. For this purpose, we created a 3D model that provides interesting data about the possible location of these non-outcropping gravity lows that are located in the first 200 m depth.These results demonstrate that the use of the gravity and magnetic method constitutes a useful, fast, economical, robust, and reliable tool for the identification of these volcanic structures.

The Use of Grass Typology in Diagnosing and Sustainably Managing Permanent Grasslands

Permanent grasslands are characterized by herbaceous flora adapted to local conditions, with deep root systems that facilitate resource uptake and provide resistance to anthropogenic and abiotic stresses. This study aimed to develop and implement efficient diagnostic and agronomic management tools for farmers. In order to demonstrate the methodology, we selected five diverse grasslands with different characteristics. The research tested the grass typology method to diagnose these areas and establish optimal management practices based on floristic composition. The method was applied to achieve the rational management of the grasslands studied. The results provided valuable data on floristic composition, species frequency, and specific functional indices. The characterization of the five grasslands in Moșnița Nouă in Timiș County enabled us to recognize optimal grassland strategies for each area, maximizing production based on the grass typology. Thus, the study demonstrated the impact of using simplified tools to improve grassland diagnosis and management, significantly contributing to the more sustainable maintenance of the permanent grasslands for farmers.

Preserving isohydricity: vertical environmental variability explains Amazon forest water use strategies.

Increases in hydrological extremes, including drought, are expected for Amazon forests. A fundamental challenge for predicting forest responses lies in identifying ecological strategies which underlie such responses. Characterization of species-specific hydraulic strategies for regulating water use, thought to be arrayed along an 'isohydric-anisohydric' spectrum, is a widely used approach. However, recent studies have questioned the usefulness of this classification scheme, because its metrics are strongly influenced by environments, hence can lead to divergent classifications even within the same species. Here, we propose an alternative approach positing that individual hydraulic regulation strategies emerge from the interaction of environments with traits. Specifically, we hypothesize that the vertical forest profile represents a key gradient in drought-related environments (atmospheric vapor pressure deficit, soil water availability) that drives divergent tree water use strategies for coordinated regulation of stomatal conductance (gs) and leaf water potentials (ΨL) with tree rooting depth, a proxy for water availability. Testing this hypothesis in a seasonal eastern Amazon forest in Brazil, we found that hydraulic strategies indeed depend on height-associated environments. Upper canopy trees, experiencing high VPD, but stable soil water access through deep rooting, exhibited isohydric strategies, defined by little seasonal change in the diurnal pattern of gs and steady seasonal minimum ΨL. By contrast, understory trees, exposed to less variable VPD but highly variable soil water availability, exhibited anisohydric strategies, with fluctuations in diurnal gs that increased in the dry season along with increasing variation in ΨL. Our finding that canopy height structures the coordination between drought-related environmental stressors and hydraulic traits provides a basis for preserving the applicability of the isohydric-to-anisohydric spectrum, which we show here may consistently emerge from environmental context. Our work highlights the importance of understanding how environmental heterogeneity structures forest responses to climate change, providing a mechanistic basis for improving models of tropical ecosystems.

Peculiarities of water exchange of Quercus robur and Acer campestre in an oak-field maple forest

We studied the physiological and biochemical parameters of water exchange of two broadleaf forest species, Quercus robur L. and Acer campestre L., which grow under different levels of water supply. The study was conducted in the lower third of the northern slope and the middle third of the southern exposure slope in the “Viyskovyi” ravine. It was established that the content of total water in the leaves of Q. robur is higher than that of A. campestre under both mesophilic and xerophilic conditions. In A. campestre, the gradual dehydration of leaves during the growing season is more pronounced. The water-holding capacity of the leaves increases in both species, especially in July and August on the southern exposure slope, which is consistent with changes in the content of hydrophilic colloids. This can be considered as an adaptation of plants against rigorous hydrothermal conditions. The leaves of A. campestre retain water better and are characterized by a greater number of hydrophilic colloids compared to the leaves of Q. robur at different levels of water supply. Under xerophilic growth conditions, the suction power of the cellular junctions of leaves is more significant than under mesophilic conditions. At both experimental sites, this indicator is always higher in case of A. campestre, while the difference is greater only under xerophilic conditions. The increase in suction force in leaf cells occurs in parallel with the increase in soil dryness. The leaves of A. campestre have a greater water deficit and suction power, better water-holding capacity due to a greater content of hydrophilic colloids, and a lower intensity of transpiration. The leaves of Q. robur have a lower water deficit and a lower water-holding capacity, which is based on the ability to resist the lack of moisture by the development of a deep root system that allows water to be absorbed from its deep horizons. The obtained data make it possible to clarify the peculiarities of the water regime of tree species during their simultaneous growth in forest phytocoenoses and adaptation to different levels of soil moisture.

Effect of localized fertilizer application on deep root development during early growth in upland rice under upland condition

ABSTRACT The effects of localized fertilizer (LF) application on changes in root system architecture (RSA) of upland rice seedlings under upland condition were evaluated, and root traits important for deep root development were identified using three root box experiments (Exps). Fertilizer was homogeneously mixed and broadcasted on the soil surface in two control treatments, while in three LF treatments, it was point-placed at 2.5, 7.5 and 12.5 cm below the soil surface. Nitrogen (N) fertilizer in Exp. 1, phosphorus (P) fertilizer in Exp. 2 and compound fertilizer with nitrogen, phosphorus and potassium (NPK) in Exp. 3 were used to compare the effects of LF. Localized N and NPK application altered the RSA through root proliferation and increasing root length percentage around the fertilizer-applied area, whereas localized P application had no effect on both root and shoot development. Deep root and shoot development were decreased with localized NPK application compared to homogeneously mixed control treatment but were maintained with localized N application, when applied at deeper soil depths. Furthermore, the increase in deep root length (DRL) was closely related to the increase in both total root length (TRL) and deep root length ratio (DRR). DRR increased with TRL in Exps. 2 and 3, while it was independent from TRL in Exp. 1, suggesting that DRL can be promoted by increasing DRR regardless of TRL. These results showed that localized N application at deeper soil depths could modify RSA of upland rice seedlings grown under upland condition without affecting shoot growth.

Three-dimensional image analysis specifies the root distribution for drought avoidance in the early growth stage of rice.

Root system architecture (RSA) plays a key role in plant adaptation to drought because deep rooting enables better water uptake than shallow rooting under terminal drought. Understanding RSA during early plant development is essential for improving crop yields, as early drought can affect subsequent shoot growth. Herein, we demonstrate that root distribution in the topsoil significantly impacts shoot growth during the early stages of rice (Oryza sativa) development under drought, as assessed through three-dimensional (3D) image analysis. We used 109 F12 recombinant inbred lines (RILs) obtained from a cross between shallow-rooting lowland rice and deep-rooting upland rice, representing a population with diverse RSA. We applied a moderate drought during the early development of rice grown in a plant pot (25cm height) by stopping irrigation 14 days after sowing (DAS). Time-series RSA at 14, 21, and 28 DAS was visualized by X-ray computed tomography, and subsequently compared between drought and well-watered conditions. Following this analysis, we further investigated drought-avoidant RSA by testing 20 randomly selected RILs under drought conditions. We inferred the root location that most influences shoot growth using a hierarchical Bayes approach: the root segment depth, which positively impacted shoot growth, ranged between 1.7-3.4cm under drought conditions and between 0.0-1.7cm under well-watered conditions. Drought-avoidant RILs had a higher root density in the lower layers of the topsoil compared to the others. Fine classification of soil layers using 3D image analysis revealed that increasing root density in the lower layers of the topsoil, rather than in the subsoil, is advantageous for drought avoidance during the early growth stage of rice.

Water use characteristics and drought tolerant ability of different winter wheat cultivars assessed under whole growth circle and at seedling stage

Using drought-resistant cultivars is important to increase crop production in water limited regions. Cultivar performance is influenced by genetic, management and environmental factors, and selection good performance cultivars is often a challenge. Five seasons (2016–2021) of field experiments and three seedling growing durations in a greenhouse, both under three water supply levels (serious water deficit, moderate water deficit and normal water supply), were conducted to assess 10 winter wheat cultivars for their water use characteristics and drought tolerance ability based on seven drought resistance indices and agronomic traits. The performance of the cultivars varied seasonally under field growing conditions. Drought resistance screened by a single index or based on the results from a single season was inconsistent. To avoid seasonal changes in cultivar performance, principal component analyses (PCA) and hierarchical cluster analysis (HCA) were conducted based on the seven indices to classify the ten cultivars into four types of drought responses. The drought resistance classification under field growing conditions at the grain yield level was highly consistent with that obtained under greenhouse growing conditions for biomass at the seedling stage. The results showed that the biomass at the seedling growing stage of the winter wheat cultivars could be used to predict the yield performance and water use characteristics when grown in the field under different water supply conditions. Precisely controlled greenhouse pot experiments could amplify the water use characteristics of different wheat cultivars for assessment. The cultivars with strong stomatal control ability had higher drought resistance and biomass production. Under field growing conditions, lower canopy temperature, deep root growth, a high root/shoot ratio and the maintenance of stomatal conductance under water stress were associated with high drought resistance. These findings provide references for selection methods and indicators for assessing drought-resistant winter wheat cultivars under different growing conditions.