Plant root systems and associated symbiotic organisms act as critical links between the growing shoot and the rhizosphere, providing both vital nutrients and water to sustain growth. Many tools have been developed to study plant root systems; however, the efficient quantification of root traits remains a key bottleneck to effectively utilizing expanding collections of genomic and germplasm resources during the study of root system development and function. This dissertation presents results from root system phenotyping research where root phenotyping platforms were developed and used to investigate the genetic components of root system architecture and development in crop plants. It begins with a review chapter that discusses the importance of root system architecture (RSA) during resource acquisition and provides an overview of established root growth and measurement techniques while highlighting modern root phenotyping approaches that have been developed for genetic mapping studies. ...
ROOT HAIR DEFECTIVE SIX-LIKE4 (RSL4) is necessary and sufficient for root hair elongation in Arabidopsis thaliana. Root hair length is determined by the duration for which RSL4 protein is present in the developing root hair. The aim of this research was to identify genes regulated by RSL4 that affect root hair growth. To identify genes regulated by RSL4, we identified genes whose expression was elevated by induction of RSL4 activity in the presence of an inhibitor of translation. Thirty-four genes were identified as putative targets of RSL transcriptional regulation, and the results suggest that the activities of SUPPRESSOR OF ACTIN (SAC1), EXOCSYT SUBUNIT 70A1 (EXO70A1), PEROXIDASE7 (PRX7) and CALCIUM-DEPENDENT PROTEIN KINASE11 (CPK11) are required for root hair elongation. These data indicate that RSL4 controls cell growth by controlling the expression of genes encoding proteins involved in cell signalling, cell wall modification and secretion.
When entering the differentiation zone, the elongating root cells that are programmed to become trichoblasts drastically add a new growth pattern to allow the highly localized emergence of root hairs. The initiation of a root hair is characterized on the level of gene expression patterns (for review, see Schiefelbein, 2000). On the level of cell physiology, specific enzymes or proteins need to restructure a defined spot of the apical outer periclinal cell wall to allow local wall loosening and bulging. At the time of root hair initiation, inside the cytoplasm actin and microtubules rearrange (Emons and Derksen, 1986; Baluška et al., 2000a, 2000b). A highly localized acidification (pH 4.5) of the cell wall is associated with the initiation process (Bibikova et al., 1998). Once the initiation is completed, the wall pH returns to the pH (approximately 6) found in the rest of the trichoblast. Besides pH changes, other factors are likely to be important to predict the future site of root hair ...
Rice is one of the major pathways of arsenic (As) exposure in human food chain, threatening over half of the global population. Greenhouse pot experiments were conducted to examine the effects of Si application on iron (Fe) plaque formation, As uptake and rice grain As speciation in indica and hybrid rice genotypes with different radial oxygen loss (ROL) ability. The results demonstrated that Si significantly increased root and grain biomass. Indica genotypes with higher ROL induced greater Fe plaque formation, compared to hybrid genotypes and sequestered more As in Fe plaque. Silicon applications significantly increased Fe concentrations in iron plaque of different genotypes, but it decreased As concentrations in the roots, straws and husks by 28-35%, 15-35% and 32-57% respectively. In addition, it significantly reduced DMA accumulation in rice grains but not inorganic As accumulation. Rice of indica genotypes with higher ROL accumulated lower concentrations of inorganic As in grains than ...
Changes in growth, porosity, and radial oxygen loss from adventitious roots of selected mono- and dicotyledonous wetland species with contrasting types of ...
We found both altered root epidermis specification and cortex cell fate in the hda19 mutant. Based on the results of additional cortex cell divisions (Fig. 1, A and B), the disappearance of the cortex marker CO2pro:NLS-YFP signal, and altered expression level of cortex-specific gene expression in hda19 (Fig. 3, A-F), we conclude that HDA19 affects root cortex cell fate. Our results indicate that the abnormality of epidermal cell patterning is derived from abnormal cortex differentiation. In particular, no direct link was found between HDA19 and multiple epidermal pattern genes (Supplemental Figs. S2 and S3), and a ground tissue-specific promoter driving HDA19 was able to fully rescue the epidermal phenotype (Fig. 3, K-N). This supports the hypothesis that positional information originating in the cortex plays a role in determining epidermal cell fate in the Arabidopsis root.. HDA19 acts through interaction with SCR and by directly binding SCR target genes. Interaction between HDA19 and SCR is ...
Discoveries on the genetics of resource acquisition efficiency are limited by the ability to measure plant roots in sufficient number and with adequate genotypic variability. This paper presents a root phenotyping study that explores ways to combine live imaging and computer algorithms for model-based extraction of root growth parameters. The study is based on a subset of barley Recombinant Chromosome Substitution Lines (RCSLs) and a combinatorial approach was designed for fast identification of the regions of the genome that contribute the most to variations in root system architecture (RSA). Results showed there was a strong genotypic variation in root growth parameters within the set of genotypes studied. The chromosomal regions associated with primary root growth differed from the regions of the genome associated with changes in lateral root growth. The concepts presented here are discussed in the context of identifying root QTL and its potential to assist breeding for novel crops with ...
Water relations and root growth of shortleaf pine (Pinus echinata Mill.) were studied four weeks after seedlings from a half-sib family had been transplanted to one of three regimes of soil water availability at a root zone temperature of either 15 or 20 °C. About one-third of the variation in new root growth was explained by the root zone environment. The interaction between root zone temperature and soil water availability accounted for 10% of the variation in new root growth. In the most favorable root environment, new roots averaged 620 mm2 of projected surface area. Leaf water potential increased exponentially with new root projected surface area, becoming constant at about 300 mm2. Leaf conductance and root system water flux increased linearly with new root growth. ...
Limitation of immobile nutrients, such as iron (Fe) and phosphate (P), induces the development of additional root hairs that lead to an increase of the absorptive surface of the root. The increased root hair frequency of Fe- and P-deficient Arabidopsis was realized by different strategies. Phosphate-deficient plants increased the number of root hairs while in Festarved plants root hairs were branched. The Fe and P starvation responses in plants are thought to be regulated by a systemic signaling mechanism that communicates the nutrient status of the shoot to the root and by a local signaling mechanism that perceives the Fe or P availability in the soil. The influence of local and systemic signals on the respective root hair phenotype was investigated in split-root experiments. This treatment was combined with either a nutrient-sufficient or -deficient shoot. The root hair branching typical of Fe-deficient plants only occured in the presence of both a local and a systemic Fe-deficiency signal. As ...
In Arabidopsis, lateral root formation is a post-embryonic developmental event, which is regulated by hormones and environmental signals. In this study, via analyzing the expression of cyclin genes during lateral root (LR) formation, we report that cytokinins (CTKs) inhibit the initiation of LR through blocking the pericycle founder cells cycling at the G2 to M transition phase, while the promotion by CTK of LR elongation is due to the stimulation of the G1 to S transition. No significant difference was detected in the inhibitory effect of CTK on LR formation between wild-type plants and mutants defective in auxin response or transport. In addition, exogenously applied auxin at different concentrations could not rescue the CTK-mediated inhibition of LR initiation. Our data suggest that CTK and auxin might control LR initiation through two separate signaling pathways in Arabidopsis. The CTK-mediated repression of LR initiation is transmitted through the two-component signal system and mediated by ...
Tweet Plant Roots - Im going to beat on that drum again! Plant root systems - unfortunately - are the most neglected and least maintained part of the plant. Yet they are probably the most vital. Because these underground parts […]
Split-root systems (SRS) have many applications in plant sciences, but their implementation, depending on the experimental design, can be difficult and time-consuming. Additionally, the system is not exempt from limitations, since the time required for the establishment of the SRS imposes a limit to how early in plant development experiments can be performed. Here, we optimized and explained in detail a method for establishing a SRS in young Arabidopsis thaliana seedlings, both in vitro and in soil. We found that the partial de-rooting minimized the recovery time compared to total de-rooting, thus allowing the establishment of the split-root system in younger plants. Analysis of changes in the Arabidopsis leaf proteome following the de-rooting procedure highlighted the distinct metabolic alterations that totally and partially de-rooted plants undergo during the healing process. This system was also validated for its use in drought experiments, as it offers a way to apply water-soluble compounds to
Image: A Simplified Model for Jasmonate-Stimulated Root Hair Development in Arabidopsis. (Image by HAN Xiao) They also discovered that the endogenous CORONATINE-INSENSITIVE1 (COI1) and JASMONATE ZIM ZIM-DOMAIN (JAZ) -mediated jasmonate signaling pathway is critical for root hair development. The disruption of the COI1 receptor or accumulation of a JAZ repressor (e.g. JAZ4 or JAZ8) decreased root hair length. Further investigation showed that several JAZ repressors interactedwithRHD6 and RSL1, two bHLH transcription factors crucial for root hair development. JAZ proteins repressed the transcriptional function of RHD6 and interfered with the interaction between RHD6 and RSL1. Phenotypic analysis showed that jasmonate promoted root hair growth in a manner dependent on RHD6and RSL1. It also showed that overexpressing RHD6 largely rescued the root hair-defective phenotypes of coi1-2 and JAZ8-ΔJas-9 plants. Our study provides a mechanistic understanding of how JAZ repressors directly regulate ...
Chambliss New Phytol 2745-2750 ArticleTitleEpidermal cell differentiation in Arabidopsis determined by a Myb homolog, CPC. New Phytol (2000a) Sollner Am J Bot 44:596-601, Ryu KH, Kang YH, Y-h P, Hwang I, Schiefelbein J, Lee MM (2005) The WEREWOLF MYB protein directly regulates CAPRICE transcription during cell fate specification in the Arabidopsis root epidermis. Lockwood CAS Y (1999) DB FF Curr Opin Plant Biol J Exp Bot Poethig Handle1:CAS:528:DyaL38XlsVWrsbw%3D 206 Plant Cell Occurrence J Cell Sci HH Okada Root hairs are extensions of the epidermal cells on the surface of the root, and are continually being sloughed off by the soil and regrown. 407-417 W M Combining phylogenetics and transcriptomics, the authors have discovered conservation of a core set of root hair genes across all vascular plants, which may derive from an ancient program for unidirectional cell growth coopted for root hair development during vascular plant evolution. 166 5 (1993) 262 A Handle7687216, BC Stevenson Linstead ...
Visual examination of roots from 12,000 mutagenized Arabidopsis seedlings has led to the identification of more than 40 mutants impaired in root hair morphogenesis. Mutants from four phenotypic classes have been characterized in detail, and genetic tests show that these result from single nuclear recessive mutations in four different genes designated RHD1, RHD2, RHD3, and RHD4. The phenotypic analysis of the mutants and homozygous double mutants has led to a proposed model for root hair development and the stages at which the genes are normally required. The RHD1 gene product appears to be necessary for proper initiation of root hairs, whereas the RHD2, RHD3, and RHD4 gene products are required for normal hair elongation. These results demonstrate that root hair development in Arabidopsis is amenable to genetic dissection and should prove to be a useful model system to study the molecular mechanisms governing cell differentiation in plants.. ...
The root epidermis is involved in nutrition and defense against pathogens. This tissue is composed of only two cell types. These cell types can be distinguished from the differentiation zone where trichoblast cells are producing root hairs and atrichoblasts are remaining non-hair cells. Root hairs are thought to be important in water and nutrient uptake. The differentiation of trichoblast involve positional information from the cortex.. ...
A balanced supply of essential nutrients is an important factor influencing root architecture in many plants, yet data related to the interactive effects of two nutrients on root growth are limited. Here, we investigated the interactive effect between phosphorus (P) and magnesium (Mg) on root growth of Arabidopsis grown in pH-buffered agar medium at different P and Mg levels. The results showed that elongation and deviation of primary roots were directly correlated with the amount of P added to the medium but could be modified by the Mg level, which was related to the root meristem activity and stem-cell division. High P enhanced while low P decreased the tip-focused fluorescence signal of auxin biosynthesis, transport, and redistribution during elongation of primary roots; these effects were greater under low Mg than under high Mg. The altered root growth in response to P and Mg supply was correlated with AUX1, PIN2, and PIN3 mRNA abundance and expression and the accumulation of the protein. ...
Author summary Plants thrive in highly heterogenous soils. How they compute a multitude of contrasting stimuli and mount an adaptive response without a centralized information processing unit is an intriguing question. For instance, below ground, roots can sense and respond to the single or multiple nutrient stresses, and adjust its growth rate accordingly. Nevertheless, the genetic architecture of root growth responses under single and combined stress remains poorly understood. To fill this gap in our understanding about such crucial phenomenon for plant survival, we explored the natural variation of root growth rate (RGR) in Arabidopsis grown under single and combined nutritional stress, including deficiencies of iron (-Fe), zinc (-Zn), phosphate and iron (-P-Fe) and phosphate and zinc (-P-Zn). Our GWAS revealed distinct genetic architectures underlying root growth responses to single or combined nutrient stresses. By integrating GWAS and coexpression networks, we identified and validated genes
During the post-embryonic development of plants, new axes of growth emerge through lateral or adventitious organogenesis, and the reiteration of this process builds up the complex pattern of a plant body. Regulation of such lateral or adventitious organogenesis provides a flexible way for plants to alter their form and resource allocation in response to environmental changes or after injury. In this context, lateral or adventitious organogenesis plays an essential role in the post-embryonic development and survival of plants.. Among the processes of lateral and adventitious organogeneses, lateral root formation has been extensively studied by various approaches using the model plant, Arabidopsis thaliana. Lateral root formation is considered to consist of two distinct phases: lateral root initiation and the establishment of the root apical meristem (Laskowski et al., 1995; Celenza et al., 1995). The histology of both these phases have been described in detail (Malamy and Benfey, 1997). During ...
Non‐destructive methods to quantify the root system architecture of a plant grown in soil are essential to aid our understanding of the factors that impact plant root development in natural environments
Methylation of lysine 4 in histone 3 (H3K4) is a post-translational modification that promotes gene expression. H3K4 methylation can be reversed by specific demethylases with an enzymatic Jumonji C domain. In Arabidopsis thaliana, H3K4-specific JUMONJI (JMJ) proteins distinguish themselves by the association with an F/Y-rich (FYR) domain. Here, we report that jmj14 mutations partially suppress reduced root meristem size and growth vigor of brevis radix (brx) mutants. Similar to its close homologs, JMJ15, JMJ16 and JMJ18, the JMJ14 promoter confers expression in mature root vasculature. Yet, unlike jmj14, neither jmj16 nor jmj18 mutation markedly suppresses brx phenotypes. Domain-swapping experiments suggest that the specificity of JMJ14 function resides in the FYR domain. Despite JMJ14 promoter activity in the mature vasculature, jmj14 mutation affects root meristem size. However, JMJ14 protein is observed throughout the meristem, suggesting that the JMJ14 transcript region contributes ...
The phenotypic analysis of root system growth is important to inform efforts to enhance plant resource acquisition from soils; however, root phenotyping remains challenging because of the opacity of soil, requiring systems that facilitate root system visibility and image acquisition. Previously reported systems require costly or bespoke materials not available in most countries, where breeders need tools to select varieties best adapted to local soils and field conditions. Here, we report an affordable soil-based growth (rhizobox) and imaging system to phenotype root development in glasshouses or shelters. All components of the system are made from locally available commodity components, facilitating the adoption of this affordable technology in low-income countries. The rhizobox is large enough (approximately 6000 cm2 of visible soil) to avoid restricting vertical root system growth for most if not all of the life cycle, yet light enough (approximately 21 kg when filled with soil) for routine ...
Maize (Zea mays) is not only a key human food and animal feed crop throughout the world but also an important raw material for the food industry and energy production plants [1]. Low phosphate concentrations are frequently a constraint for maize growth and development, and therefore, enormous quantities of phosphate fertilizer are expended in maize cultivation, which increases the cost of planting. Although the total amount of phosphorus (P) in the soil may be high, plants mainly absorb P in the inorganic form (Pi), which is present at a low concentration, limiting plant growth and development [2].. Phosphorus is an essential macronutrient for all living organisms and plays important roles in energy metabolism; biosynthesis of nucleic acids, phospholipids and membranes; cellular signal transduction and the regulation of many enzymes [3, 4]. Plants have evolved two broad strategies to cope with phosphate starvation, which involve changes in physiology, biochemistry and root morphology that ...
Taproots develop from the radicle of a seed, forming the primary root. It branches off to secondary roots, which in turn branch to form tertiary roots. These may further branch to form rootlets. For most plants species the radicle dies some time after seed germination, causing the development of a fibrous root system, which lacks a main downward-growing root. Most trees begin life with a taproot,[3] but after one to a few years the main root system changes to a wide-spreading fibrous root system with mainly horizontal-growing surface roots and only a few vertical, deep-anchoring roots. A typical mature tree 30-50 m tall has a root system that extends horizontally in all directions as far as the tree is tall or more, but as much as 100% of the roots are in the top 50 cm of soil. Soil characteristics strongly influence the architecture of taproots; for example, deep rich soils favour the development of vertical taproots in many oak species such as Quercus kelloggii, while clay soils promote the ...
One of the responses of plants to low sources of external phosphorus (P) is to modify root architecture. In Arabidopsis thaliana plantlets grown on low P, the primary root length (PRL) is reduced whereas lateral root growth is promoted. By using the Bay-0 × Shahdara recombinant inbred line (RIL) population, we have mapped three quantitative trait loci (QTL) involved in the root growth response to low P. The Shahdara alleles at these three QTL promote the response of the primary root to low P (i.e. root length reduction). One of these QTL, LPR1, located in a 2.8 Mb region at the top of chromosome 1, explains 52% of the variance of the PRL. We also detected a single QTL associated with primary root cell elongation in response to low P which colocalizes with LPR1. LPR1 does not seem to be involved in other typical P-starvation responses such as growth and density of root hairs, excretion of acid phosphatases, anthocyanin accumulation or the transcriptional induction of the P transporter Pht1;4. LPR1 might
The root system is essential for the growth and development of plants. In addition to anchoring the plant in the ground, it is the site of uptake of water and minerals from the soil. Plant root systems show an astonishing plasticity in their architecture, which allows for optimal exploitation of div …
Glacial forefields host young, poorly developed soils with highly unstable environmental conditions. Root system contribution to soil stabilization is a well-known phenomenon. Identifying the functional traits and root morphology of pioneer vegetation that establish on forefields can provide information useful in the practical application of plants in land restoration of high altitude mountain sites.This study aims to gather information on the root morphology and biomechanical characteristics of the 10 most dominant pioneer plant species of the forefield of Lys Glacier (NW Italian Alps).X-ray Computed Tomography (X-ray CT) was used to visualize and quantify non-destructively the root architecture of the studied species. Samples were cored directly from the forefield. Data on root traits such as total root length, rooting depth, root diameter, root length density and number of roots in relation to diameter classes as well as plant height were determined and compared between species. Roots were ...
We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study we used a 15N depletion method that allowed for the measurement of nitrate-N uptake rates on intact individual fine roots of known age. We expected that N uptake would decline rapidly as fine roots aged regardless of the environmental conditions and species used. We compared age dependent uptake patterns of young grape cuttings with those of mature vines and with those of tomato. Although patterns of declining uptake with increasing root age were similar for all species and conditions tested large differences in maximum N uptake rates existed between young cuttings and mature vines and between woody and herbaceous species. Maximum rates were 10-fold higher for tomato and 3-fold higher for the grape cuttings when compared with ...
We only have a limited understanding of the nutrient uptake physiology of individual roots as they age. Despite this shortcoming the importance of nutrient uptake processes to our understanding of plant nutrition and nutrient cycling cannot be underestimated. In this study we used a 15N depletion method that allowed for the measurement of nitrate-N uptake rates on intact individual fine roots of known age. We expected that N uptake would decline rapidly as fine roots aged regardless of the environmental conditions and species used. We compared age dependent uptake patterns of young grape cuttings with those of mature vines and with those of tomato. Although patterns of declining uptake with increasing root age were similar for all species and conditions tested large differences in maximum N uptake rates existed between young cuttings and mature vines and between woody and herbaceous species. Maximum rates were 10-fold higher for tomato and 3-fold higher for the grape cuttings when compared with ...
Soil nutrients are essential for plant growth and metabolism. Plant roots acquire nutrients from soils and have developed adaptive mechanisms to ensure nutrient acquisition under the varying nutritional conditions in soil. When plants are deprived of nutrients such as potassium, roots activate two important adaptive mechanisms for the uptake of nutrients that help support growth and survival. One adaptation involves deploying additional nutrient acquisition and remobilization systems, such as transporters (Ashley et al., 2006; Gierth and Maser, 2007) or channels (Lebaudy et al., 2007). The other adaptation involves changes in developmental processes of roots, including primary root growth, lateral root formation, and root hair elongation (Lopez-Bucio et al., 2003). Architectural changes in root systems, in response to nutrition deprivation, help plants to take up more nutrients by increasing the absorptive surface in specific regions of the soil.. Plants require potassium in large quantities for ...
FERONIA (FER) is a receptor-like kinase (RLK) involved in a large number of processes in Arabidopsis. FER plays a role in cell elongation, mechanosensing, regulation of seed size, immunity and root hair development. A common theme in many of these processes is the involvement of FER as a regulator of location-specific growth (often called polar growth) and consistent with this observation FER is also known to interact with proteins that regulate the cytoskeleton (called Rho of plants, ROPs). The peptide, Rapid- Alkalinisation Factor 1 (RALF1), has been shown to elicit FER dependent signalling. Focusing within root tissue and using RALF1, we seek to explore early signalling events upon FER elicitation and clarify the interaction between FER and ROPs, using co-immunoprecipitation (CoIP) and mass spectrometry (MS). We have identified potential FER interactors, including Receptor for Activated C kinase 1B (RACK1B) and have identified two proteins, CAND1 and ILITYHIA, which are common between FER, ...
Differences among plant species in morphology and patterns of growth are assumed to influence their ability to acquire resources and, consequently, their competitive ability. Despite the acknowledged importance of below-ground resources for plant growth, our knowledge of species differences in root morphology of non-agricultural plants is limited. Comparisons of root morphology, growth rate and topology of seedlings of 12 herbaceous plant species that occur in early to mid-successional fields revealed significant differences among species that were largely related to life history. Annuals grew faster and produced longer and more branched roots than did biennials and perennials. Only among the annuals was there a positive correlation between seed mass and root growth. The grasses allocated proportionately more biomass to roots than the dicots, but did not differ in root length or branching pattern. As seedlings, all 12 species exhibited a herringbone topology; although after 10 d there were ...
Soil pollutants may affect root growth through interactions among phytohormones like auxin and jasmonates. Rice is frequently grown in paddy fields contaminated by cadmium and arsenic, but the effects of these pollutants on jasmonates/auxin crosstalk during adventitious and lateral roots formation are widely unknown. Therefore, seedlings of Oryza sativa cv. Nihonmasari and of the jasmonate-biosynthetic mutant coleoptile photomorphogenesis2 were exposed to cadmium and/or arsenic, and/or jasmonic acid methyl ester, and then analysed through morphological, histochemical, biochemical and molecular approaches.In both genotypes, arsenic and cadmium accumulated in roots more than shoots. In the roots, arsenic levels were more than twice higher than cadmium levels, either when arsenic was applied alone, or combined with cadmium. Pollutants reduced lateral root density in the wild -type in every treatment condition, but jasmonic acid methyl ester increased it when combined with each pollutant. ...
Soil pollutants may affect root growth through interactions among phytohormones like auxin and jasmonates. Rice is frequently grown in paddy fields contaminated by cadmium and arsenic, but the effects of these pollutants on jasmonates/auxin crosstalk during adventitious and lateral roots formation are widely unknown. Therefore, seedlings of Oryza sativa cv. Nihonmasari and of the jasmonate-biosynthetic mutant coleoptile photomorphogenesis2 were exposed to cadmium and/or arsenic, and/or jasmonic acid methyl ester, and then analysed through morphological, histochemical, biochemical and molecular approaches.In both genotypes, arsenic and cadmium accumulated in roots more than shoots. In the roots, arsenic levels were more than twice higher than cadmium levels, either when arsenic was applied alone, or combined with cadmium. Pollutants reduced lateral root density in the wild -type in every treatment condition, but jasmonic acid methyl ester increased it when combined with each pollutant. ...
Plant roots are required for the acquisition of water and nutrients, for responses to abiotic and biotic signals in the soil, and to anchor the plant in the ground. Controlling plant root architecture is a fundamental part of plant development and evolution, enabling a plant to respond to changing e …
The geometrical and topological structure of a plants root system is crucial for the success of soil exploration and for the survival of the individual. For this reason, the genetic control of root development is under enormous selection pressure at various scales, from tissue patterning at the cellular level, to the 3D branching pattern of the entire below-ground root system, which can be more extensive than the above-ground shoot system. Root apical meristems (RAMs) produce cells that will form the root system. A group of seldom-dividing cells in the root apex, known as the quiescent center (QC), is crucial for RAM activity. The cells adjacent to the QC, initial cells/stem cells, divide asymmetrically to produce two cell populations, one for self-renewal and another population that will undergo transient amplification within the RAM, or meristematic zone, and later will be displaced into the elongation zone. After anisotropic expansion, cells that reached their final size leave the elongation zone.
We describe a novel robotic facility that makes it possible to conduct high-content, miniaturized screens for the effects of small molecules on both root and shoot development in a 96-well microtitre plate format. At the heart of this automated platform is a novel seedling growth device, the Phytostrip, which has been specifically designed to allow detailed analysis of the effects of chemical treatments on root system architecture. Roots are a particularly attractive subject for phenotyping studies because of the large number of individual traits that can be readily visualised (Fig. 4) and the extent to which each of these traits is responsive to environmental factors [30, 50]. Many previous investigations into the genetic control of plant responses to abiotic and biotic stresses have focussed on root development [51, 52] and powerful robotic and imaging technologies have been developed to streamline the quantitative analysis of root growth and architecture of soil-grown roots [53, 54, 55]. ...
Root hairs are extensions of the epidermal cells on the surface of the root, The parenchyma cells are living, thin-walled and undergo repeated cell division for growth of the plant. They arise from the nodes and internodes of the stem, e.g., Prop roots of banyan, stilt roots of sugarcane, clasping roots of money plant and roots from the stem cuttings. Water and dissolved minerals from the soil move into the Root does not bear nodes, internodes, leaves or buds (exceptions are sweet potato, wood apple etc.) A taproot, (With Methods), Industrial Microbiology, How is Cheese Made Step by Step: Principles, Production and Process, Enzyme Production and Purification: Extraction & Separation Methods , Industrial Microbiology, Fermentation of Olives: Process, Control, Problems, Abnormalities and Developments, The best answers are voted up and rise to the top. As the name implies, it is the site of rapid and extensive cell elongation. Privacy Policy3. The tiny root The stems are the trunks and branches. ...
The effect of soil acidity on root and rhizosheath development in wheat and barley seedlings was investigated in an acid Ferrosol soil to which various amounts of lime (CaCO3) were applied to modify s
Root hairs, tubular structures that emerge from plant root epidermal cells, grow through localized exocytosis of cell-wall matrix, a process involving actin-dependent delivery of Golgi-derived vesicles containing matrix material to the growing tip. Researchers have long recognized that the cell nucleus maintains a fixed distance from the apex of the growing root hair. The mechanisms by which the nucleus maintains this position, however, and how it pertains to tip growth, remain unclear. Ketelaar et al. used time-lapse photography of Arabidopsis root hair tips to investigate nuclear behavior during root hair growth and did pharmacological analysis to implicate the actin cytoskeleton in nuclear localization. During active growth, the nucleus maintained a fixed distance from the tip, moving backwards when growth ceased to a random position in the root hair. In mutants with branched hairs, branches emerged from the site at which the nucleus was located; thereafter, nuclei moved between growing ...
A cell wall with intercellular spaces. Start studying root hair cell diagram biology year 10 gcse. Gcse Biology Root Hair Cell Diagram Diagram Quizlet Root hair cell root cortex cells xylem leaf mesophyll cells exam tip if you are asked to identify the xylem or phloem in a diagram showing a cross section of a […]
The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria which degrade PAHs have been isolated from the rhizospheres of plant species with varied biological traits, however, it is not known what phytochemicals promote contaminant degradation. One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular, the phenolic compounds - morin, caffeic acid, and protocatechuic acid - appear to be linked to bacterial ...
1. Tomlinson I (2013) Doubling food production to feed the 9 billion: a critical perspective on a key discourse of food security in the UK. Journal of rural studies 29: 81-90.. 2. Zhu C, Kobayashi K, Loladze I, Zhu J, Jiang Q, et al. (2018) Carbon dioxide (CO2) levels this century will alter the protein, micronutrients, and vitamin content of rice grains with potential health consequences for the poorest rice-dependent countries. Science advances 4: eaaq1012. doi: 10.1126/sciadv.aaq1012 29806023. 3. Hilty FM, Arnold M, Hilbe M, Teleki A, Knijnenburg JTN, et al. (2010) Iron from nanocompounds containing iron and zinc is highly bioavailable in rats without tissue accumulation. Nature nanotechnology 5: 374. doi: 10.1038/nnano.2010.79 20418865. 4. Abelson PH (1999) A potential phosphate crisis. Science 283: 2015-2015. doi: 10.1126/science.283.5410.2015 10206902. 5. Cordell D, Drangert J-O, White S (2009) The story of phosphorus: global food security and food for thought. Global environmental change ...
TY - JOUR. T1 - Cryptochrome photoreceptors cry1 and cry2 antagonistically regulate primary root elongation in Arabidopsis thaliana. AU - Canamero, Roberto C.. AU - Bakrim, Nadia. AU - Bouly, Jean Pierre. AU - Garay, Alvaro. AU - Dudkin, Elizabeth Anne. AU - Habricot, Yvette. AU - Ahmad, Margaret. PY - 2006/10/1. Y1 - 2006/10/1. N2 - Cryptochromes are blue-light receptors controlling multiple aspects of plant growth and development. They are flavoproteins with significant homology to photolyases, but instead of repairing DNA they function by transducing blue light energy into a signal that can be recognized by the cellular signaling machinery. Here we report the effect of cry1 and cry2 blue light receptors on primary root growth in Arabidopsis thaliana seedlings, through analysis of both cryptochrome-mutant and cryptochrome-overexpressing lines. Cry1 mutant seedlings show reduced root elongation in blue light while overexpressing seedlings show significantly increased elongation as compared to ...
Lateral roots are initiated postembryonically in response to environmental cues, enabling plants to explore efficiently their underground environment. However, the mechanisms by which the environment determines the position of lateral root formation are unknown. In this study, we demonstrate that in Arabidopsis thaliana lateral root initiation can be induced mechanically by either gravitropic curvature or by the transient bending of a root by hand. The plant hormone auxin accumulates at the site of lateral root induction before a primordium starts to form. Here we describe a subcellular relocalization of PIN1, an auxin transport protein, in a single protoxylem cell in response to gravitropic curvature. This relocalization precedes auxin-dependent gene transcription at the site of a new primordium. Auxin-dependent nuclear signaling is necessary for lateral root formation; arf7/19 double knock-out mutants normally form no lateral roots but do so upon bending when the root tip is removed. Signaling ...
TY - JOUR. T1 - Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L.. AU - Ng, Yuk Kiu. AU - Moore, Randy. N1 - Funding Information: This research represents a portion of a thesis submitted in partial fulfillment of the requirements for a Master of Science degree in Biology at Baylor University. We thank Prof. J. D. Smith for providing us with the vp-9 mutants and Dr Jim Barrentine for providing us with Fluridone. This research was supported by funds provided by the University Research Committee and the Department of Biology of Baylor University.. PY - 1985/3. Y1 - 1985/3. N2 - The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation ...
Lateral roots originate deep within the parental root from a small number of founder cells at the periphery of vascular tissues and must emerge through intervening layers of tissues. We describe how the hormone auxin, which originates from the developing lateral root, acts as a local inductive signal which re-programmes adjacent cells. Auxin induces the expression of a previously uncharacterized auxin influx carrier LAX3 in cortical and epidermal cells directly overlaying new primordia. Increased LAX3 activity reinforces the auxin-dependent induction of a selection of cell-wall-remodelling enzymes, which are likely to promote cell separation in advance of developing lateral root primordia.. Nature Cell Biology 10 (8), 946-954 ...
Phosphate (Pi), an essential macronutrient for growth and development of plant, is often limiting in soils. Plants have evolved an array of adaptive strategies including modulation of root system architecture (RSA) for optimal acquisition of Pi. In rice, a major staple food, RSA is complex and comprises embryonically developed primary and seminal roots and post-embryonically developed adventitious and lateral roots. Earlier studies have used variant hydroponic systems for documenting the effects of Pi deficiency largely on primary root growth. Here, we report the temporal effects of Pi deficiency in rice genotype MI48 on 15 ontogenetically distinct root traits by using easy-to-assemble and economically viable modified hydroponic system. Effects of Pi deprivation became evident after 4 d- and 7 d-treatments on 2 and 8 different root traits, respectively. The effects of Pi deprivation for 7 d were also evident on 14 different root traits of rice genotype Nagina 22 (N22). There were genotypic differences
Root system architecture is important for water acquisition and nutrient acquisition for all crops. In soybean breeding programs, wild soybean alleles have been used successfully to enhance yield and seed composition traits, but have never been investigated to improve root system architecture. Therefore, in this study, high-density single-feature polymorphic markers and simple sequence repeats were used to map quantitative trait loci (QTLs) governing root system architecture in an inter-specific soybean mapping population developed from a cross between Glycine max and Glycine soja. Wild and cultivated soybean both contributed alleles towards significant additive large effect QTLs on chromosome 6 and 7 for a longer total root length and root distribution, respectively. Epistatic effect QTLs were also identified for taproot length, average diameter, and root distribution. These root traits will influence the water and nutrient uptake in soybean. Two cell division-related genes (D type
Certain crosses of common bean (Phaseolus vulgaris) result in temperature-dependent hybrid weakness associated with a severe root phenotype. This is controlled by the interaction of the root- and shoot-expressed semidominant alleles dosage-dependent lethal 1 (DL1) and DL2, which communicate via long-distance signaling. Previously, apparent reciprocal effects on root growth and the restoration of normal root growth by exogenous sucrose led to the hypothesis that the dosage-dependent lethal (DL) system may control root-shoot carbon partitioning. Here, recombinant inbred lines were used to map the DL loci and physiological and biochemical analysis, including metabolite profiling, was used to gain new insights into the signaling interaction and the root phenotype. It is shown that the DL system does not control root-shoot carbon partitioning and that roots are unlikely to die from carbon starvation. Instead, root death likely occurs by defense-related programmed cell death, as indicated by salicylic ...
Roots show positive hydrotropism in response to moisture gradients, which is believed to contribute to plant water acquisition. This article reviews the recent advances of the physiological and molecular genetic studies on hydrotropism in seedling roots of Arabidopsis thaliana. We identified MIZU-KUSSEI1 (MIZ1) and MIZ2, essential genes for hydrotropism in roots; the former encodes a protein of unknown function, and the latter encodes an ARF-GEF (GNOM) protein involved in vesicle trafficking. Because both mutants are defective in hydrotropism but not in gravitropism, these mutations might affect a molecular mechanism unique to hydrotropism. MIZ1 is expressed in the lateral root cap and cortex of the root proper. It is localized as a soluble protein in the cytoplasm and in association with the cytoplasmic face of endoplasmic reticulum (ER) membranes in root cells. Light and ABA independently regulate MIZ1 expression, which influences the ultimate hydrotropic response. In addition, MIZ1 ...
Root release of phytosiderophores (PSs) is an important step in iron (Fe) acquisition of grasses, and this adaptive reaction of plants is affected by various plant and environmental factors. The objectives of this study were to study the effects of varied nitrogen (N) supply on (1) root and leaf concentrations of methionine, a precursor in the PS biosynthesis, (2) PS release from roots, (3) mobilization and uptake of Fe from (59) Fe-labeled Fe(III)-hydroxide [(59) Fe(OH)(3) ] and (4) root uptake of (59) Fe-labeled Fe(III)-deoxymugineic acid (DMA) by durum wheat (Triticum durum, cv. Balcali2000) plants grown in a nutrient solution. Enhanced N supply from 0.5 to 6 mM in a nutrient solution significantly increased the root release of PS under Fe deficiency. High N supply was also highly effective in increasing mobilization and root uptake of Fe from (59) Fe-hydroxide under low Fe supply. With adequate Fe, N nutrition did not affect mobilization and uptake of Fe from (59) Fe(OH)(3) . Root uptake and shoot
Auxin is involved in many aspects of root development and physiology, including the formation of lateral roots. Improving our understanding of how the auxin response is mediated at the protein level over time can aid in developing a more complete molecular framework of the process. This study evaluates the effects of exogenous auxin treatment on the Arabidopsis root proteome after exposure of young seedlings to auxin for 8, 12, and 24 h, a timeframe permitting the initiation and full maturation of individual lateral roots. Root protein extracts were processed to peptides, fractionated using off-line strong-cation exchange, and analyzed using ultra-performance liquid chromatography and data independent acquisition-based mass spectrometry. Protein abundances were then tabulated using label-free techniques and evaluated for significant changes. Approximately 2000 proteins were identified during the time course experiment, with the number of differences between the treated and control roots increasing over
Specific root respiration rates typically increase with increasing tissue N concentration. As a result, it is often assumed that external factors inducing greater root N concentration, such as chronic N deposition, will lead to increased respiration rates. However, enhanced N availability also alters root biomass, making the ecosystem‐level consequences on whole‐root‐system respiration uncertain. The objective of this study was to determine the effects of chronic experimental N deposition on root N concentrations, specific respiration rates, and biomass for four northern hardwood forests in Michigan. Three of the six measurement plots at each location have received experimental N deposition (3 g ‐N m−2 yr−1) since 1994. We measured specific root respiration rates and N concentrations of roots from four size classes (|0.5, 0.5-1, 1-2, and 2-10 mm) at three soil depths (0-10, 10-30, and 30-50 cm). Root biomass data for the same size classes and soil depths was used in combination with specific
Experiments were conducted to compare differences in P uptake characteristics between two winter wheat cultivars Stephens and Yamhill (Triticum aestivum L) as related to root morphologies. Root length, root surface area and mean root radius were compared. Plant roots and shoots were separately analyzed for P content. The cultivars were grown in a growth chamber with a 16 hour light period at 22° C and an 8 hour darkness at 16° C for approximately three weeks. A growth medium deficient only in P and with a pH high enough (6.4 to 6.6) to prevent Al toxicity was prepared by mixing a silt loam and a sand. Soil P variables were established by adding phosphoric acid (H₃PO₄) to the soil at rates of 0, 25 and 100 ug P g⁻¹ soil. The root growth rates of the cultivars were exponential with time. Stephens had more rapid root growth rate, greater root length and root surface area than Yamhill. There were no significant cultivar differences in root radius. Stephens had higher root to shoot ratio ...
In order to test the hypothesis that multiple integrated root phenotypes would co-optimize drought tolerance, we phenotyped the root anatomy and architecture of 400 mature maize genotypes under well-watered and water-stressed conditions in the field. We found substantial variation in all 23 root phenes measured. A phenotypic bulked segregant analysis revealed that bulks representing the best and worst performers in the field displayed distinct root phenotypes. In contrast to the worst bulk, the root phenotype of the best bulk under drought consisted of greater cortical aerenchyma formation, more numerous and narrower metaxylem vessels, and thicker nodal roots. Partition against medians (PAM) clustering revealed several clusters of unique root phenotypes related to plant performance under water stress. Clusters associated with improved drought tolerance consisted of phene states that likely enable greater soil exploration by reallocating internal resources to greater root construction (increased ...
PINOID, a serine threonine protein kinase in Arabidopsis, controls auxin distribution through a positive control of subcellular localization of PIN auxin efflux carriers. Compared with the rapid progress in understanding mechanisms of auxin action in dicot species, little is known about auxin action in monocot species. Here, we describe the identification and characterization of OsPID, the PINOID ortholog of rice. Phylogenetic analysis showed that the rice genome contains a single PID ortholog, OsPID. Constitutive overexpression of OsPID caused a variety of abnormalities, such as delay of adventitious root development, curled growth of shoots and agravitropism. Abnormalities observed in the plants that overexpress OsPID could be phenocopied by treatment with an inhibitor of active polar transport of auxin, indicating that OsPID could be involved in the control of polar auxin transport in rice. Analysis of OsPID mRNA distribution showed a complex pattern in shoot meristems, indicating that it ...
Regulation of gene expression is crucial for organism growth, and it is one of the challenges in systems biology to reconstruct the underlying regulatory biological networks from transcriptomic data. The formation of lateral roots in Arabidopsis thaliana is stimulated by a cascade of regulators of which only the interactions of its initial elements have been identified. Using simulated gene expression data with known network topology, we compare the performance of inference algorithms, based on different approaches, for which ready-to-use software is available. We show that their performance improves with the network size and the inclusion of mutants. We then analyze two sets of genes, whose activity is likely to be relevant to lateral root initiation in Arabidopsis, and assess causality of their regulatory interactions by integrating sequence analysis with the intersection of the results of the best performing methods on time series and mutants. The methods applied capture known interactions ...
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Using PI as an apoplastic tracer, we evaluated the presence of an apoplastic barrier in the myb36 mutants. To quantify this barrier function, we counted the number of endodermal cells from the onset of elongation to the point where PI fluorescence was no longer observed in the stele-facing cell wall of the endodermis. We found that blockage of PI penetration into the stele in the myb36 mutants was delayed compared with wild-type and was similar to the delay observed in esb1-1 (Fig. 2D). This result indicates that the loss of the centrally located Casparian strip in myb36 eliminates the apoplastic barrier in that region of the root. Furthermore, the ectopic lignin-like material deposited in the corners of myb36 endodermal cells is not able to form an effective barrier to apoplastic transport. However, the diffusional barrier in myb36 is recovered in the more mature region of the root, where suberin is normally deposited in wild-type (1).. Similar to esb1-1 and casp1;casp3 (4), the myb36 mutants ...
Both trichomes and root hairs, the rhizoids of many vascular plants, are lateral outgrowths of a single cell of the epidermal layer. Root hairs form from trichoblasts, the hair-forming cells on the epidermis of a plant root. Root hairs vary between 5 and 17 micrometres in diameter, and 80 to 1,500 micrometres in length (Dittmar, cited in Esau, 1965). Root hairs can survive for two to three weeks and then die off. At the same time new root hairs are continually being formed at the top of the root. This way, the root hair coverage stays the same. It is therefore understandable that repotting must be done with care, because the root hairs are being pulled off for the most part. This is why planting out may cause plants to wilt. The genetic control of patterning of trichomes and roots hairs shares similar control mechanisms. Both processes involve a core of related transcription factors that control the initiation and development of the epidermal outgrowth. Activation of genes that encode specific ...
Both trichomes and root hairs, the rhizoids of many vascular plants, are lateral outgrowths of a single cell of the epidermal layer. Root hairs form from trichoblasts, the hair-forming cells on the epidermis of a plant root. Root hairs vary between 5 and 17 micrometres in diameter, and 80 to 1,500 micrometres in length (Dittmar, cited in Esau, 1965). Root hairs can survive for two to three weeks and then die off. At the same time new root hairs are continually being formed at the top of the root. This way, the root hair coverage stays the same. It is therefore understandable that repotting must be done with care, because the root hairs are being pulled off for the most part. This is why planting out may cause plants to wilt. The genetic control of patterning of trichomes and roots hairs shares similar control mechanisms. Both processes involve a core of related transcription factors that control the initiation and development of the epidermal outgrowth. Activation of genes that encode specific ...
Nitrogen (N), the primary limiting factor for plant growth and yield in agriculture, has a patchy distribution in soils due to fertilizer application or decomposing organic matter. Studies in solution culture over-simplify the complex soil environment where microbial competition and spatial and temporal heterogeneity challenge roots ability to acquire adequate amounts of nutrients required for plant growth. In this study, various ammonium treatments (as 15N) were applied to a discrete volume of soil containing tomato (Solanum lycopersicum) roots to simulate encounters with a localized enriched patch of soil. Transcriptome analysis was used to identify genes differentially expressed in roots 53 hrs after treatment. The ammonium treatments resulted in significantly higher concentrations of both ammonium and nitrate in the patch soil. The plant roots and shoots exhibited increased levels of 15N over time, indicating a sustained response to the enriched environment. Root transcriptome analysis identified
Formulated with nine wild-crafted traditional botanicals, New Roots Essence promotes the elimination of accumulated toxins through the kidneys, skin, and mucous membranes. Nutrient-rich burdock root serves as the botanical backbone of New Roots Essence with its potent ant... Where can I buy New Roots Essence
General Hydroponics EuroGrower - 8 Pots Complete EuroGrower - 8 Pots Complete (eco-4746-2) EuroGrower - 8 Pots Complete The new EuroGrower from General Hydroponics is the ideal system for someone new to gardening. The EuroGrower provides users with a simple, elegant approach to home hydroponics. The heart of the EuroGrower is our custom designed 40-gallon Panda reservoir, which is more than adequate for its eight 2-gallon buckets. Growers can use the EuroGrower virtually anywhere. The EuroGrower comes complete with Flora Series nutrients, which are currently the industry standard. EuroGrower General Hydroponics EuroGrower - Drip Hydroponic System - The new EuroGrower from General Hydroponics is the ideal system for someone new to gardening. The EuroGrower provides users with a simple, yet elegant approach to home hydroponics. The heart of the EuroGrower is our custom designed 40-gallon Panda reservoir, which is more than adequate for its eight 2-gallon buckets. Whether using a soil or soil-less medium,
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With climate change and an ever-increasing human population threatening food security, developing a better understanding of the genetic basis of crop performance under stressful conditions has become increasingly important. Here, we used genome-wide association studies to genetically dissect variation in seedling growth traits in cultivated sunflower (Helianthus annuus L.) under well-watered and water-limited (i.e., osmotic stress) conditions, with a particular focus on root morphology. Water limitation reduced seedling size and produced a shift toward deeper rooting. These effects varied across genotypes, and we identified 13 genomic regions that were associated with traits of interest across the two environments. These regions varied in size from a single marker to 186.2 Mbp and harbored numerous genes, some of which are known to be involved in the plant growth/development as well as the response to osmotic stress. In many cases, these associations corresponded to growth traits where the common allele
When primary Arabidopsis roots grow down a tilted agar plate, they do not elongate following the gravitational vector along a straight line, but instead they slant noticeably to the right-hand. This process is seen mostly in the ecotypes Wassilewskji
Scarecrow appears in Batman: Arkham Knight. Seeking revenge on Batman, Scarecrow re-emerges in Gotham City two years after being attacked by Killer Croc in Arkham Asylum. Scarecrows appearance has changed drastically following his encounter with Killer Croc, with Scarecrow now sporting a leg brace and having his gas mask now permanently grafted on his face. Scarecrow joins forces with a man known only as the Arkham Knight, a paramilitary commander who commands a militia that answers only to him and Scarecrow. In his latest campaign against Gotham, Scarecrow unites all of Gothams criminals in an attempt to finally kill Batman. At the beginning of the game, Scarecrow threatens to release his new strain of fear toxin on the streets of Gotham, resulting in the evacuation of most of the citys civilian population. The Arkham Knights militia then conquers Gotham, preventing the authorities from interfering with Scarecrows plan. Batman soon discovers that Scarecrows new fear gas is being ...
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Potassium ion and Na+ influx and efflux rates into and from excised barley roots are compared with the maximum capacity of accumulation. Potassium ion and Na+ influx and efflux involve a cation exchange that is independent of simultaneous exchange of the accompanying anion. These exchange fluxes depend on the concentration and cation composition of the solutions from which they originate. Selective differences between K+ and Na+ fluxes are sufficient to account for a cationic distribution within the roots that differs markedly from that of the external solution and that persists for extended time periods. The accumulation maximum is a cation exchange equilibrium with the cation influx and efflux rates approaching equality. The equilibrium level is independent of the individual cation fluxes and the external solution concentration. It is a finite quantity which appears to be determined by the internal anion concentration including accumulated as well as endogenous anions.. ...
After wounding, nitric oxide promotes, in AR development in response to nitric oxide has been also observed in, ss [95]. controlling the localization and transcription of, 78]. Phytohormones, together with many other internal and external stimuli, coordinate and guide every step of AR formation from the first event of cell reprogramming until emergence and outgrowth. ; Benson, F.C. fic Ethylene-Insensitive Mutants in Arabidopsis. ; Black, C.R. The WUSCHEL-related homeobox gene WOX11 is, Zhao, Y.; Cheng, S.; Song, Y.; Huang, Y.; Zhou, S.; Liu, X.; Zhou, D.-X. Provide Support 3. Adventitious roots form from stem tissues, generally as a result of damage or removal of the primary root system. In addition, gene products related to gibberellin (GA) biosynthesis and signaling, auxin homeostasis, and xylem differentiation were confirmed to participate in adventitious root formation. From Wikipedia, the free encyclopedia. All rights reserved. ; Kumari, S.; Cho, M.; Lee, S.H. which encodes an AP2/ERF ...
The word mycorrhizae comes from the Greek words for fungus and root, and refers to the symbiotic relationship that exists between plant roots and certain fungi. In natural settings, these mycorrhizal fungi are present in the soil in association with plant roots. The fungi colonize by attaching to the surface of the root (ectomycorrhizal) or to the inside of the root cells (endomycorrhizal). Then they send their filaments (called mycelium) into the surrounding soil, effectively extending the plants roots and root absorbing capacity ten to 1000 times-far beyond what the plant can do alone.3 Several miles of these ultra-fine filaments can be present in less than a thimbleful of soil. Mycorrhizae supply the water and nutrients needed by the plant for establishment and survival, and, in return, receive from the plant roots sugars and other compounds needed by the fungus. Mycorrhizae are much smaller than roots, so they can easily penetrate into smaller spaces between soil particles, where they ...
The patterned assignment of different cell fates, shortly termed patterning, lies at the basis of growth, development and reproduction of multicellular organisms. The single-layered epidermal tissue of Arabidopsis thaliana is characterized by hair-like cellular protuberances, the root hairs and the leaf trichomes, respectively, emerging from a subset of cells. Specification of hair and non-hair cell fate occurs in a tightly controlled fashion by gene regulatory networks of overlapping components that, however, often have opposite functions in root and shoot. Moreover, the root epidermis displays organization in hair- and non-hair cell files while leaf trichomes are distributed in a regular spacing pattern over the leaf. In contrast to the shoot, assignment of a cell files fate in the root epidermis depends on the cells position with respect to the underlying root cortical cell layer, which defines cells atop the border of two cortical cells as hair- and cells atop a single cortical cell as ...