Larger Root System Research Articles

Root exudation patterns of contrasting rice (Oryza sativa L.) lines in response to P limitation

Main conclusionRice exudation patterns changed in response to P deficiency. Higher exudation rates were associated with lower biomass production. Total carboxylate exudation rates mostly decreased under P-limiting conditions.Within the rhizosphere, root exudates are believed to play an important role in plant phosphorus (P) acquisition. This could be particularly beneficial in upland rice production where P is often limited. However, knowledge gaps remain on how P deficiency shapes quality and quantity of root exudation in upland rice genotypes. We therefore investigated growth, plant P uptake, and root exudation patterns of two rice genotypes differing in P efficiency in semi-hydroponics at two P levels (low P = 1 µM, adequate P = 100 µM). Root exudates were collected hydroponically 28 and 40 days after germination to analyze total carbon (C), carbohydrates, amino acids, phenolic compounds spectrophotometrically and carboxylates using a targeted LC–MS approach. Despite their reported role in P solubilization, we observed that carboxylate exudation rates per unit root surface area were not increased under P deficiency. In contrast, exudation rates of total C, carbohydrates, amino acids and phenolics were mostly enhanced in response to low P supply. Overall, higher exudation rates were associated with lower biomass production in the P-inefficient genotype Nerica4, whereas the larger root system with lower C investment (per unit root surface area) in root exudates of the P-efficient DJ123 allowed for better plant growth under P deficiency. Our results reveal new insights into genotype-specific resource allocation in rice under P-limiting conditions that warrant follow-up research including more genotypes.

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.

Genome-wide association studies of root system architecture traits in a broad collection of Brassica genotypes.

The root systems of Brassica species are complex. Eight root system architecture (RSA) traits, including total root length, total root surface area, root average diameter, number of tips, total primary root length, total lateral root length, total tertiary root length, and basal link length, were phenotyped across 379 accessions representing six Brassica species (B. napus, B. juncea, B. carinata, B. oleracea, B. nigra, and B. rapa) using a semi-hydroponic system and image analysis software. The results suggest that, among the assessed species, B. napus and B. oleracea had the most intricate and largest root systems, while B. nigra exhibited the smallest roots. The two species B. juncea and B. carinata shared comparable root system complexity and had root systems with larger root diameters. In addition, 313 of the Brassica accessions were genotyped using a 19K Brassica single nucleotide polymorphism (SNP) array. After filtering by TASSEL 5.0, 6,213 SNP markers, comprising 5,103 markers on the A-genome (covering 302,504 kb) and 1,110 markers on the C-genome (covering 452,764 kb), were selected for genome-wide association studies (GWAS). Two general linear models were tested to identify the genomic regions and SNPs associated with the RSA traits. GWAS identified 79 significant SNP markers associated with the eight RSA traits investigated. These markers were distributed across the 18 chromosomes of B. napus, except for chromosome C06. Sixty-five markers were located on the A-genome, and 14 on the C-genome. Furthermore, the major marker-trait associations (MTAs)/quantitative trait loci (QTLs) associated with root traits were located on chromosomes A02, A03, and A06. Brassica accessions with distinct RSA traits were identified, which could hold functional, adaptive, evolutionary, environmental, pathological, and breeding significance.

TabHLH27 orchestrates root growth and drought tolerance to enhance water use efficiency in wheat.

Cultivating high-yield wheat under limited water resources is crucial for sustainable agriculture in semiarid regions. Amid water scarcity, plants activate drought response signaling, yet the delicate balance between drought tolerance and development remains unclear. Through genome-wide association studies and transcriptome profiling, we identified a wheat atypical basic helix-loop-helix (bHLH) transcription factor (TF), TabHLH27-A1, as a promising quantitative trait locus candidate for both relative root dry weight and spikelet number per spike in wheat. TabHLH27-A1/B1/D1 knock-out reduced wheat drought tolerance, yield, and water use efficiency (WUE). TabHLH27-A1 exhibited rapid induction with polyethylene glycol (PEG) treatment, gradually declining over days. It activated stress response genes such as TaCBL8-B1 and TaCPI2-A1 while inhibiting root growth genes like TaSH15-B1 and TaWRKY70-B1 under short-term PEG stimulus. The distinct transcriptional regulation of TabHLH27-A1 involved diverse interacting factors such as TaABI3-D1 and TabZIP62-D1. Natural variations of TabHLH27-A1 influence its transcriptional responses to drought stress, with TabHLH27-A1Hap-II associated with stronger drought tolerance, larger root system, more spikelets, and higher WUE in wheat. Significantly, the excellent TabHLH27-A1Hap-II was selected during the breeding process in China, and introgression of TabHLH27-A1Hap-II allele improved drought tolerance and grain yield, especially under water-limited conditions. Our study highlights TabHLH27-A1's role in balancing root growth and drought tolerance, providing a genetic manipulation locus for enhancing WUE in wheat.

Neem's promise: The way to a sustainable future and eco-friendly biopesticides

Modern agriculture must include pest management since pests can seriously harm crops and lower yields, resulting in considerable financial losses. Conventional chemical insecticides have been used as the main method of pest management, but their detrimental effects on the environment and human health have inspired the quest for new environmentally friendly options. In this situation, Azadirachta indica showed promise as a sustainable and eco-friendly biopesticide. This research shows many aspects for Azadirachta indica as an environment friendly biopesticide. Neem is well known for having antiviral, antiseptic, and antifungal characteristics, which make it a crucial component in remedies for many illnesses, skin disorders, and mouth care. It is also beneficial to the environment. When added to the soil, its seeds and leaves help increase the fertility of the soil and structure. Additionally, the tree's large root system helps stop soil erosion. Azadirachta indica, is a great asset in the field of pest control and agricultural sustainability due to its repellent and antifeedant qualities. These characteristics are a result of neem's bioactive substances, known as Azadirachtin which has been the subject of in-depth study and use because of its function as a natural repellent and antifeedant Azadirachtin is a potent natural insect growth regulator because it interferes with beetle feeding, molting, and reproduction. Furthermore, the eco-friendliness of azadirachtin and its safety for people and non-target animals highlight its essential function in sustainable pest management techniques, aiding in the advancement of environmentally friendly and healthier agricultural systems. The neem plant is a unique botanical gem that has enormous medicinal, farming, and cultural significance. Its adaptability and environmental friendliness make it an important resource for sustainable agriculture and human well-being. Three commercialized neem-based formulations were tested aphid, Myzus persicae, including Azatrol, Triple Action Neem Oil (70% neem oil), and Pure Neem Oil (100% neem oil) in greenhouse and laboratory settings. A bioassay using a leaf disc choice test indicated that of the established neem-based insecticides tested were effective against the aphid at the recommended concentrations. However, a doubling in the quantity of Azatrol and Triple Action Neem Oil resulted in a 50% decrease in the number of aphids landing on handled leaf tissue compared to untreated leaf tissue.

N2 Fixation, N Transfer, and Land Equivalent Ratio (LER) in Grain Legume-Wheat Intercropping: Impact of N Supply and Plant Density.

Intercropping legumes with cereals can lead to increased overall yield and optimize the utilization of resources such as water and nutrients, thus enhancing agricultural efficiency. Legumes possess the unique ability to acquire nitrogen (N) through both N2 fixation and from the available N in the soil. However, soil N can diminish the N2 fixation capacity of legumes. It is postulated that in intercropping, legumes uptake N mainly through N2 fixation, leaving more soil N available for cereals. The latter, in turn, has larger root systems, allowing it to explore greater soil volume and absorb more N, mitigating its adverse effects on N2 fixation in legumes. The goal of this study was to evaluate how the supply of N affects the intercropping of faba beans (Vicia faba L.) and peas (Pisum sativum L.) with wheat under varying plant densities and N levels. We measured photosynthetic traits, biomass production, the proportion of N derived from air (%Ndfa) in the shoot of the legumes, the N transferred to the wheat, and the land equivalent ratio (LER). The results revealed a positive correlation between soil N levels and the CO2 assimilation rate (An), chlorophyll content, and N balance index (NBI) in wheat. However, no significant effect was observed in legumes as soil N levels increased. Transpiration (E) increased in wheat intercropped with legumes, while stomatal conductance (gs) increased with N addition in all crops. Water use efficiency (WUE) decreased in faba beans intercropped with wheat as N increased, but it showed no significant change in wheat or peas. The shoot dry matter of wheat increased with the addition of N; however, the two legume species showed no significant changes. N addition reduced the %Ndfa of both legume species, especially in monoculture, with peas being more sensitive than faba beans. The intercropping of wheat alleviated N2 fixation inhibition, especially at high wheat density and increased N transfer to wheat, particularly with peas. The LER was higher in the intercropping treatments, especially under limited N conditions. It is concluded that in the intercropping of wheat with legumes, the N2 fixation inhibition caused by soil N is effectively reduced, as well as there being a significant N transfer from the legume to the wheat, with both process contributing to increase LER.

KEANEKARAGAMAN JENIS TUMBUHAN BAWAH BERPOTENSI OBAT DI KAWASAN GUNUNG TILU KABUPATEN KUNINGAN JAWA BARAT

Undergrowth is a type of basic vegetation found under forest stands except for forest tree regeneration, which includes grasses, herbs and shrubs. Undergrowth plants have a primary function in conserving soil and water. This is because the undergrowth has a large root system that produces dense clumps and is able to prevent soil erosion, as a protector of the soil from raindrops and runoff, also plays a role in increasing organic matter in the soil as green manure and mulch. Utilization of undergrowth plants as a source of medicines has an important role and is an alternative for the community to maintain health and treat a disease. The purpose of this study was to determine the diversity of undergrowth plants and to identify undergrowth plants with medicinal potential as a source of information for the community and area managers. The method used is the transect method/checkered line. Sampling plots were taken in 3 routes, namely the Citambelang, Ebeg-ebeg, and Bakukung routes. Each path consists of 9 sample plots. The results of the undergrowth inventory were then calculated the Important Value Index (IVI) and Species Diversity Index (H' The results showed that there were 44 types of undergrowth found in the Gunung Tilu area from 31 families with a total of 668 individuals. The largest IVI was found in cakar ayam (Selaginella doerderleinii) with a value of 22.64 and the smallest IVI was for kemukus (Piper cubeba) and meniran (Phyllanthus urinaria) with a value of 0.88. For undergrowth plants that have medicinal potential, 28 species from 23 families and 521 individuals were found. The diversity index in undergrowth in the Mount Tilu area is categorized as low with an index value (H'<1) which is 0.32. This information is very important for future management of the Mount Tilu forest area.

The impact of PEG-induced drought stress on early vigour traits of bread wheat

ABSTRACT A total of 11 genotypes from the collection of 101 bread wheat genotypes, with desirable traits in terms of increased tolerance to drought, were chosen for parents and eight crosses were performed. Number of seminal roots (NSR), total root length (TRL), root dry mass (RDM), number of shoots per plant (NS), main shoot length (MSL), shoot dry mass (SDM), number of leaves per plant (NL), leaf area per plant (LA), leaf dry mass (LDM), aboveground dry mass (ADM), SDM/LDM, RDM/ADM were analysed at the boot stage (Z45). The F1 progeny had on average higher mean values (P < 0.001) than parents for four traits: RDM, NS, LA and RDM/ADM. The highest broad sense heritability values were determined for RDM (97.6%) and NSR (93.9%). Factor analysis indicated that a large root system, higher RDM and TRL are associated with higher NS, NL, LA and LDM. For Euclid x CHI-4 and WWBMC2 x Ingenio combinations the highest heterosis values were observed for TRL (34.1%) and SDM (23.7%), for RDM (28.6%) and LA (26.8%), respectively. PEG-induced drought stress in the seedling stage, in most of the new germplasm, caused an increased redistribution of dry matter in the root compared to the stem.

Tall fescue tiller survival over summer in a subtropical environment: The role of the size and depth of root systems

AbstractPasture persistence is a key determinant of the economic and environmental performance of pastoral animal production systems. Large and deep root systems that help resist summer water stress have been proposed as a relevant trait for vegetative persistence of perennial temperate forage species growing in subtropical climates or under future climatically challenging scenarios. In a previous study [Jauregui et al., 2017. Persistence of tall fescue in a subtropical environment: Tiller survival over summer in response to flowering control and nitrogen supply. Grass and Forage Science 72, 454–466] we have shown that nitrogen fertilization and grazing management aimed at ‘control flowering’ increased the survival of tall fescue tillers during harsh summers in Uruguay (lat. 32°S). Here we assessed: (i) to what extent tiller survival is mediated by root system size in spring and (ii) what consequences tiller survival entails for root mass, depth and morphology the following autumn. In two field experiments, significant increases in tiller survival in response to nitrogen fertilization and grazing management (+60% and +80% in 2011/12 and 2012/13, respectively) were not related to concomitant effects on the size or depth of the root system in spring (p &gt; .10). Even when six‐fold within‐treatment variation in root mass was observed, within‐treatment variation in summer tiller survival was little affected (&lt;15%, p = .08). In turn, differences in tiller survival over summer affected little root system characteristics the following autumn. Therefore, we found scant support for the hypothesis that large and deep root systems contribute to survival of tall fescue tillers in this subtropical humid climate. Except for soils with less than 30 mm of plant available water holding capacity, summer water deficits did not induce severe tiller mortality in tall fescue in this climate.

Varietal responses of root characteristics to low nitrogen application explain the differing nitrogen uptake and grain yield in two rice varieties.

Rice root characteristics are tightly associated with high-efficient nitrogen uptake. To understand the relationship of root plastic responses with nitrogen uptake when reducing nitrogen application for green rice production, a hydroponic experiment and a soil pot experiment were conducted under high (HN) and low (LN) nitrogen applications, using two rice (Oryza sativa L.) varieties, NK57 and YD6, three nitrogen absorption traits (total nitrogen accumulation, net NH4 + influx on root surface, nitrogen uptake via apoplasmic pathway) and root characteristics were investigated. In comparison with HN, LN significantly reduced nitrogen absorption and grain yield in both varieties. Concomitantly, there was a decrease in total root length, root surface area, root number, root volume, and root cortical area under LN, while single root length, root aerenchyma area, and root lignin content increased. The expression of OsAMT1;1 and OsAMT1;2 down-regulated in both varieties. The findings revealed that YD6 had smaller reduction degree for the three nitrogen absorption traits and grain yield, accompanied by smaller reduction degree in total root length, root surface area, root cortical area, and expression of the two genes under LN. These root characteristics were significantly and positively correlated with the three nitrogen absorption traits and grain yield, especially under LN. These results indicate that a large root system, lower reduction degree in several root characters, and high expression of OsAMT genes in YD6 explains its high nitrogen accumulation and grain yield under reduced nitrogen application. The study may provide rationale for developing varieties with low nitrogen fertilizer requirements for enabling green rice production.

Synergistic Effects of Subsoil Calcium in Conjunction with Nitrogen on the Root Growth and Yields of Maize and Soybeans in a Tropical Cropping System

A large part of Brazilian maize is double-cropped after soybeans, when water shortages are very frequent. A larger root system can mitigate drought stress and enable better nitrogen (N) use. Alleviating acidity and applying gypsum can increase root growth and N-use efficiency in maize, which has a more aggressive root system than soybeans. However, it is not known how these factors interact in integrated cropping systems, or how soybeans respond to them. Soybean and maize root growth and grain yields as affected by soil Ca enrichment using lime and gypsum, along with the N rates applied to maize intercropped with Guinea grass (Megathyrsus maximus), were assessed in a medium-term field experiment. Liming resulted in greater root growth for both crops; however, when lime was used in conjunction with gypsum, root growth was further enhanced. The total maize grain yield was 35% higher compare to the control when gypsum was used in conjunction with lime; however, subsoil Ca enrichment increased the total soybean grain yield by 8% compared to the control. Nitrogen fertilization increased the total maize grain yield by 36%, with a more expressive increase when applying 160 kg ha−1 or more, and despite a positive effect on soybean grain yields in the long term, this response seems not to be a direct effect of the N applied to the maize. Both subsoil Ca enrichment and N application to maize increase root growth and the total yield of the system.

Potassium Efficiency of Wheat and Sugar Beet Evaluated Under Field Conditions

This study was conducted to investigate the potassium (K)efficiency of wheat and sugar beet under field conditions and to identifythe varying mechanisms or factors behind their efficiency. Data wereobtained from a long term fertilizer experiment, on a K "fixing" sandyclay loam in Bavaria, southern Germany, in which K fertilization ratesvaried from 0 to 1000 kg K ha-1 year-1 with the last K application in 1986.In 2003, sugar beet and spring wheat were sown on March 13 th and April4 th , respectively. At 4 and 5 harvests for wheat and sugar beet,respectively, random samples of shoots, roots and soil of each speciesfrom the unfertilized (-K) and the highest fertilizer level of 1000 kg K ha-1(+K) treatments were analyzed. Sugar beet and wheat had similar Kefficiency producing 76 % and 80 % beet and grain yield on unfertilizedcompared with fertilized treatments, respectively. As compared to wheat,sugar beet had a higher internal K requirement, two times higher shootgrowth rate (GRs), 34% to 48 % of the wheat root length (RL), andconsequently a larger GR/RL, that is higher demand for K uptake on theroots. However, sugar beet showed an exceptionally high uptakeefficiency of the single roots or influx, which was 5 times higher inunfertilized treatments, as compared with wheat. Wheat K efficiency wasattributed to a higher utilization efficiency or lower internal requirement,slow growing shoots and a large root system. Further investigations arenecessary to study the mechanism by which sugar beet was able toachieve a higher influx than wheat.

Root traits of perennial C4 grasses contribute to cultivar variations in soil chemistry and species patterns in particulate and mineral‐associated carbon pool formation

AbstractRecent studies have indicated that the C4 perennial bioenergy crops switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii) accumulate significant amounts of soil carbon (C) owing to their extensive root systems. Soil C accumulation is likely driven by inter‐ and intraspecific variability in plant traits, but the mechanisms that underpin this variability remain unresolved. In this study we evaluated how inter‐ and intraspecific variation in root traits of cultivars from switchgrass (Cave‐in‐Rock, Kanlow, Southlow) and big bluestem (Bonanza, Southlow, Suther) affected the associations of soil C accumulation across soil fractions using stable isotope techniques. Our experimental field site was established in June 2008 at Fermilab in Batavia, IL. In 2018, soil cores were collected (30 cm depth) from all cultivars. We measured root biomass, root diameter, specific root length, bulk soil C, C associated with coarse particulate organic matter (CPOM) and fine particulate organic matter plus silt‐ and clay‐sized fractions, and characterized organic matter chemical class composition in soil using high‐resolution Fourier‐transform ion cyclotron resonance mass spectrometry. C4 species were established on soils that supported C3 grassland for 36 years before planting, which allowed us to use differences in the natural abundance of stable C isotopes to quantify C4 plant‐derived C. We found that big bluestem had 36.9% higher C4 plant‐derived C compared to switchgrass in the CPOM fraction in the 0–10 cm depth, while switchgrass had 60.7% higher C4 plant‐derived C compared to big bluestem in the clay fraction in the 10–20 cm depth. Our findings suggest that the large root system in big bluestem helps increase POM‐C formation quickly, while switchgrass root structure and chemistry build a mineral‐bound clay C pool through time. Thus, both species and cultivar selection can help improve bioenergy management to maximize soil carbon gains and lower CO2 emissions.

Phenotypic variation of root-system architecture under high P and low P conditions in potato (Solanum tuberosum L.)

BackgroundPhosphorus (P) is an essential macronutrient required for plant metabolism and growth. Its acquisition by plants depends on the availability of dissolved P in the rhizosphere and on the characteristics of P uptake mechanisms such as root-system architecture (RSA). Compared to other crops, potato (Solanum tuberosum L.) has a relatively poor P acquisition efficiency. This is mainly due to its shallow and sparsely branched root system, resulting in a rather limited exploitable soil volume. Information about potato genotypes with RSA traits suitable to improve adaptation to nutrient scarcity is quite rare. Aim of this study is to assess phenotypic variation of RSA in a potato diversity set and its reactions to P deficiency.ResultsOnly one out of 22 RSA-traits showed a significant increase under low-P conditions. This indicates an overall negative effect of P scarcity on potato root growth. Differences among genotypes, however, were statistically significant for 21 traits, revealing a high variability in potato RSA. Using a principal component analysis (PCA), we were able to classify genotypes into three groups with regard to their root-system size. Genotypes with both small and large root systems reacted to low-P conditions by in- or decreasing their relative root-system size to medium, whereas genotypes with an intermediate root system size showed little to no changes.ConclusionsWe observed a huge variation in both the potato root system itself and its adaptation to P deficiency. This may enable the selection of potato genotypes with an improved root-zone exploitation. Eventually, these could be utilized to develop new cultivars adapted to low-P environments with better resource-use efficiencies.

IBA Delivery Technique and Media Salts Affected In Vitro Rooting and Acclimatization of Eight Prunus Genotypes

Difficult-to-root plants often perform poorly during acclimatization and in vitro rooting can increase the survival and quality of plants. The influence of auxin application and mineral nutrition on in vitro rooting and subsequent effects on plant quality in eight Prunus genotypes were investigated. Microshoots were rooted in vitro on Murashige and Skoog (MS), ½ MS, Driver and Kuniyuki (DKW), or New Prunus Medium (NPM) media formulations in combination with 15 µM indole-3-butyric acid (IBA), 4-day 15 µM IBA pulse, 1 mM 30 s quick-dip, or IBA-free treatments. Shoots were observed pre- and post-acclimatization to determine rooting methods to maximize quality and minimize labor. A genotype-specific response to auxin application was observed with seven of eight genotypes achieving 100% survival when paired with the recommended IBA treatment. Peaches performed best when treated with 4-day IBA pulse or 30 s quick-dip. Rooting of P. cerasifera, it's hybrid to P. persica, and P. munsoniana all benefitted from IBA application. Shoots rooted with 15 µM IBA were smaller and lower quality in most genotypes. DKW maximized size and quality in six genotypes. Better shoots and larger root systems during in vitro rooting produced better plants in the greenhouse with no detrimental effect of callus growth. Rooting techniques to maximize plant quality while reducing labor are specified.

Plants for carbon farming and China&amp;rsquo;s roadmap for carbon neutralization

<p indent="0mm">Compared to the atmospheric CO₂ concentration of 285 parts per million (ppm) in the 1850s, the contemporary atmospheric CO₂ concentration is about <sc>415 ppm.</sc> Compared to the environment of 1850s, the increase in atmospheric CO₂ level already resulted in about 1.5°C in global air temperature and caused major negative impacts on global crop productivity, ecosystem functioning, ocean levels, and human welfare. If the global CO₂ level is left uncontrolled, the global atmospheric CO₂ level can reach <sc>1000 ppm</sc> and the global air temperature can be increased by 5°C, which can cause irreversible and severe consequences on the ecosystem functioning of our planet earth and the welfare of our human civilization. Globally, more and more countries joined the force on developing a carbon neutral society and find ways to mitigate global climate change. The Chinese government announced that China will establish a carbon neutral society by 2060, i.e., by 2060, effective strategies need to be in place to enable capturing the 2.5 billion ton of inevitably released CO₂. Various strategies are under development now to realize this goal. The solution may include capturing 0.152 billion tons of C by ocean ecosystem and 0.498 billion tons of C captured by terrestrial ecosystem. Here the carbon capture by terrestrial ecosystem includes 0.068 billion tons carbon captured by marginal land, especially desert, highly arid areas etc and application of biochar equivalent to 0.138 billion tons of C, in addition to the carbon capturing by forest, shrub, grassland ecosystem etc. In addition, 0.054 billion tons of C can be captured by physical or chemical or mechanical techniques for carbon capture use and storage (CCUS). Development of crops for carbon farming will be required to ensure realization of these goals. The features of crops for carbon farming include having high biomass, large root system, very little or zero release of methane and volatile organic carbon molecules, high nitrogen use efficiency, proper soil microbiome conferring high stress resistance and high nutrient uptake and utilization capacity, high resistance for degradation of plant root and residues, perennial, and high tolerance to stresses, such as drought, salinity, high and low temperatures. These features call for concerned efforts in studying molecular mechanisms underlying these traits, and also strategies to realize these traits in current plants. The crops for carbon farming can be developed either through <italic>de novo</italic> domestication with the support of the modern genome editing techniques, or through manipulation of current crops to gain additional features desired for crops used for carbon farming. Concerted research is also needed to develop better viable strategy to use biochar in agro-ecosystems. Biochar can be used as fertilizers and methods to improve soil quality, in addition to be a major source of carbon sink. Effective combination of photovoltaic electricity generation and plant factory can be used to develop new strategies for plant production in marginal land, which amounts to increase the “land areas” for carbon farming. To expedite development of strategies to enable carbon farming by plants, novel phenotyping and measurement protocols need to be developed to enable detailed characterization of the carbon capture, usage, and storage in different ecosystems, i.e. the forest ecosystem, agro-ecosystem, and ecosystems composed of marginal land. Novel multiscale models also need to be developed to enable not only link ecosystem level fluxes to physiological properties at the leaf, cell or even the organelle levels, which will be required to dissect factors controlling the ability of an ecosystem to capture, use and store carbon, but also to identify new options to further increase the capacity of our ecosystems to capture carbon more efficiently.

A 3D image-based modelling approach for understanding spatiotemporal processes in phosphorus fertiliser dissolution, soil buffering and uptake by plant roots

Phosphorus (P) is a key yield-limiting nutrient for crops, but the main source of P fertiliser is finite. Therefore, efficient fertilisation is crucial. Optimal P application requires understanding of the dynamic processes affecting P availability to plants, including fertiliser dissolution rate and soil buffer power. However, standard soil testing methods sample at fixed time points, preventing a mechanistic understanding of P uptake variability. We used image-based modelling to investigate the effects of fertiliser dissolution rate and soil buffer power on P uptake by wheat roots imaged using X-ray CT. We modelled uptake based on 1-day, 1-week, and 14-week dissolution of a fixed quantity of total P for two common soil buffer powers. We found rapid fertiliser dissolution increased short-term root uptake, but total uptake from 1-week matched 1-day dissolution. We quantified the large effects root system architecture had on P uptake, finding that there were trade-offs between total P uptake and uptake per unit root length, representing a carbon investment/phosphorus uptake balance. These results provide a starting point for predictive modelling of uptake from different P fertilisers in different soils. With the addition of further X-ray CT image datasets and a wider range of conditions, our simulation approach could be developed further for rapid trialling of fertiliser-soil combinations to inform field-scale trials or management.

The response of grain yield and ear differentiation related traits to nitrogen levels in maize varieties with different nitrogen efficiency

Maize (Zea mays L.) is one of the most widely distributed and important crops in China. Maize ear differentiation plays an important role grain yield formation. However, it is unclear if ear and root morphophysiology status affects yield formation by altering ear differentiation and development under different nitrogen (N) conditions. The aim of this study is to understand how the ear differentiation and development are affected by ear and root morphophysiology traits, as affected by the N rate. The experiment consisted of two N rates: high nitrogen (180 kg ha−1), and low nitrogen (60 kg ha−1). Two N-efficient varieties (NEVs) and two N-inefficient varieties (NIVs) were grown in the field. The results showed higher nitrogen accumulation and grain yield in NEVs than in NIVs, which was mainly attributed to the increased N uptake by the larger root system under both N conditions. Under high N conditions, among ear differentiation-related traits, only FR was significantly positively correlated with grain yield, and NEVs ensure FR through higher N concentration and ZR content in ear at the fertilization stage. Under low N conditions, NEVs obtained higher FP, SR and FR through higher N concentration and IAA in ear at the early stage of ear differentiation, maintained lower AR and BTL by higher RA, R-ZR and E-ZR at the late stage of ear growth. These results suggest that NEVs have a more complex mechanism for obtaining higher grain yield under low N conditions than N sufficiency, and that phytohormones play an important role in this process.

Suitability of vetiver (Vetiveria zizanioides) for removal of Cr (III) from tannery effluent using floating bed and rhizofiltration systems

Various physico-chemical methods have been employed in remediating heavy metals from wastewater, but most of them are expensive. While phytoremediation, is one cost-effective and eco-friendly technology, proves to be an alternate amongst which Vetiver, a unique tropical plant, is recognized for its large biomass and dense root system and has been proven for various remediation studies. The current research was conducted to assess the potential for Vetiver rhizofiltration of chromium. A pilot study was conducted in rhizobox wherein Vetiver was grown using sand as a medium and samples were collected from rhizobox port 1 and rhizobox port 2. Subsequently, the study was upscaled to a floating bed experiment. In both studies, Vetiver were grown under 500 mg L-1 Cr (III) solution and tannery effluent had a chromium concentration of 379 mg L-1 and the results were compared to control. Between the samples collected from port 1 and 2, the removal of chromium in port 1 was recorded to be higher than that of port 2. Moreover, the removal of chromium ions from the tannery effluent was relatively higher than the spiked solution. In both the ports, the highest removal of chromium concentration was recorded in T5 (Sand + Vetiver + Cr (III) @ 500 mg kg-1) with a removal percent of 12.59 and 10.38% in port 1 and 2, respectively. Hence, Vetiver grass has a great potential in removing pollutants like chromium from the wastewater.

Grasses and field crops reduce the concentration of resting spores of Plasmodiophora brassicae in soil under controlled conditions

AbstractClubroot, caused by Plasmodiophora brassicae, dramatically reduces yields of brassica crops, and once present in a field, can persist in the soil for many years via long‐lived resting spores. Some nonhost crops can stimulate the germination of resting spores, which reduces clubroot inoculum because the pathogen cannot complete its life cycle in the absence of a living host. The effect of selected grasses and other field crops on the concentrations of spores in soil was assessed in two replicated and repeated short‐duration (8‐week) studies under controlled conditions. The spore concentration declined precipitously in the bare soil control relative to the initial spore concentration over the course of both studies. Cultivars of meadow bromegrass, smooth bromegrass and one cultivar of perennial ryegrass reduced the spore concentration compared to the bare soil control in both repetitions of one study, while two cultivars of perennial ryegrass did not reduce the spore concentration. In a second study, spring wheat, perennial ryegrass, barley and field pea reduced spores compared to the bare soil control, but soybean did not. Our hypothesis that larger root systems would produce larger reductions in spore numbers was not supported; there was no correlation between root weight and reduction in spore concentration. We conclude that perennial grasses, spring cereals and field pea can contribute to the reduction of clubroot spores in soil. The advantage of grass crops over annual crops for clubroot management is that movement of infested soil is minimized over the entire duration of the grass stand.