INFLUENCE OF ROOT HAIRS IN SUPPLYING SOIL PHOSPHORUS TO WHEAT

1973 ◽  
Vol 53 (2) ◽  
pp. 169-175 ◽  
Author(s):  
J. B. BOLE
Keyword(s):  
Root Hair ◽  
Unit Length ◽  
Root Hairs ◽  
P Uptake ◽  
Hair Density ◽  
Wheat Roots ◽  
Soil P ◽  
Root Hair Development ◽  
Root Hair Density ◽  
Hair Development

Chromosome substitution lines of wheat (Triticum aestivum L.) showing a parental difference in root-hair development were studied under several P regimes. Average root-hair density was 45 root hairs/mm in a low-P soil compared with 60 when P supply was adequate. Soil P uptake was not closely related to root-hair density in any of the regimes. Rape roots virtually devoid of root hairs took up two to six times as much soil P per unit length as the wheat roots with root hairs. Flax roots also did not produce root hairs but absorbed more P per unit length than the wheat roots. Root-hair development did not regulate the P uptake efficiency of the wheat roots and would be expected to be even less effective in supplying other nutrients.

scholarly journals Root hair specification and its growth in response to nutrients

2021 ◽  
Vol 49 (2) ◽  
pp. 12258
Author(s):  
Xian HUANG ◽  
Tianzhi GONG ◽  
Mei LI ◽  
Cenghong HU ◽  
Dejian ZHANG ◽  
...  
Keyword(s):  
Root Hair ◽  
Reverse Genetics ◽  
Current Knowledge ◽  
Plant Root ◽  
Root Hairs ◽  
Root Surface ◽  
Root Surface Area ◽  
Root Hair Development ◽  
Hair Development ◽  
Calcium Iron

Plant root hairs are cylindrical tubular projections from root epidermal cells. They increase the root surface area, which is important for the acquisition of water and nutrients, microbe interactions, and plant anchorage. The root hair specification, the effect of root hairs on nutrient acquisition and the mechanisms of nutrients (calcium, iron, magnesium, nitrogen, phosphorus, and potassium) that affect root hair development and growth were reviewed. The gene regulatory network on root hair specification in the plant kingdom was highlighted. More work is needed to clone the genes of additional root hair mutants and elucidate their roles, as well as undertaking reverse genetics and mutant complementation studies to add to the current knowledge of the signaling networks, which are involved in root hair development and growth regulated by nutrients.

scholarly journals Rock Fragment Content in Soils Shift Root Foraging Behavior in Xerophytic Species

2021 ◽  
Author(s):  
Hui Hu ◽  
Weikai Bao ◽  
David M. Eissenstat ◽  
Long Huang ◽  
Fanglan Li
Keyword(s):  
Root Hair ◽  
Fine Root ◽  
Root Hairs ◽  
Root Traits ◽  
Rock Fragment ◽  
Hair Density ◽  
Root Branching ◽  
Root Hair Density ◽  
Branching Intensity ◽  
Rock Fragment Content

Abstract Aims Root traits associated with resource foraging, including fine-root branching intensity, root hair and mycorrhiza, may change in soils with various physical structure indicated by rock fragment content (RFC), while how these traits covariate at the level of individual root branching order is largely unknown.Methods We subjected two xerophytic species, Artemisia vestita (subshrub) and Bauhinia brachycarpa (shrub), to increasing RFC gradients (0%, 25%, 50% and 75%, v v-1) in an arid environment and measured fine-root traits related to resource foraging.Results Root hair density and mycorrhizal colonization of both species decreased with increasing root order, but increased in 3rd- and 4th-order roots at high RFCs (50% or 75%). The two species tend to produce more root hairs than mycorrhizas under the high RFCs. For both species, root hair density and mycorrhizal colonization intensity were negatively correlated with root length and root diameter. Rockiness reduced root branching intensity in both species comparing with rock-free soil. At the same level of RFC, A. vestita had thicker roots and lower branching intensity than B. brachycarpa, and tended to produce more root hairs.Conclusion Our results suggest the high RFC soil conditions stimulated greater foraging functions in higher root orders. We found evidence for a greater investment in root hairs and mycorrhizal symbioses as opposed to building an extensive root system in rocky soils. The subshrub and shrub species took different approaches to foraging in the rocky soil through distinctive trait syndromes of fine-root components.

scholarly journals Root hairs are the most important root trait for rhizosheath formation of barley (Hordeum vulgare), maize (Zea mays) and Lotus japonicus (Gifu)

2021 ◽  
Author(s):  
Emma Burak ◽  
John N Quinton ◽  
Ian C Dodd
Keyword(s):  
Zea Mays ◽  
Hordeum Vulgare ◽  
Root Hair ◽  
Root Length ◽  
Root Exudate ◽  
Lotus Japonicus ◽  
Root Hairs ◽  
Root Hair Development ◽  
Maize Genotypes ◽  
Hair Development

Abstract Background and Aims Rhizosheaths are defined as the soil adhering to the root system after it is extracted from the ground. Root hairs and mucilage (root exudates) are key root traits involved in rhizosheath formation, but to better understand the mechanisms involved their relative contributions should be distinguished. Methods The ability of three species [barley (Hordeum vulgare), maize (Zea mays) and Lotus japonicus (Gifu)] to form a rhizosheath in a sandy loam soil was compared with that of their root-hairless mutants [bald root barley (brb), maize root hairless 3 (rth3) and root hairless 1 (Ljrhl1)]. Root hair traits (length and density) of wild-type (WT) barley and maize were compared along with exudate adhesiveness of both barley and maize genotypes. Furthermore, root hair traits and exudate adhesiveness from different root types (axile versus lateral) were compared within the cereal species. Key Results Per unit root length, rhizosheath size diminished in the order of barley > L. japonicus > maize in WT plants. Root hairs significantly increased rhizosheath formation of all species (3.9-, 3.2- and 1.8-fold for barley, L. japonicus and maize, respectively) but there was no consistent genotypic effect on exudate adhesiveness in the cereals. While brb exudates were more and rth3 exudates were less adhesive than their respective WTs, maize rth3 bound more soil than barley brb. Although both maize genotypes produced significantly more adhesive exudate than the barley genotypes, root hair development of WT barley was more extensive than that of WT maize. Thus, the greater density of longer root hairs in WT barley bound more soil than WT maize. Root type did not seem to affect rhizosheath formation, unless these types differed in root length. Conclusions When root hairs were present, greater root hair development better facilitated rhizosheath formation than root exudate adhesiveness. However, when root hairs were absent root exudate adhesiveness was a more dominant trait.

scholarly journals Physiological Regulation of Root System Architecture: The Role of Ethylene and Phosphorus

2001 ◽  
Author(s):  
Amram Eshel ◽  
Jonathan P. Lynch ◽  
Kathleen M. Brown
Keyword(s):  
Root System ◽  
Root Hair ◽  
Ethylene Production ◽  
Root Architecture ◽  
Root Hairs ◽  
Phosphorus Availability ◽  
Hair Density ◽  
Root Angle ◽  
Low Phosphorus ◽  
Root Hair Density

Specific Objectives and Related Results: 1) Determine the effect of phosphorus availability on ethylene production by roots. Test the hypothesis that phosphorus availability regulates ethylene production Clear differences were found between the two plants that were studied. In beans ethylene production is affected by P nutrition, tissue type, and stage of development. There are genotypic differences in the rate of ethylene production by various root types and in the differential in ethylene production when P treatments are compared. The acceleration in ethylene production with P deficiency increases with time. These findings support the hypothesis that ethylene production may be enhanced by phosphorus deficiency, and that the degree of enhancement varies with genotype. In tomatoes the low-P level did not enhance significantly ethylene production by the roots. Wildtype cultivars and ethylene insensitive mutants behaved similarly in that respect. 2) Characterize the effects of phosphorus availability and ethylene on the architecture of whole root systems. Test the hypothesis that both ethylene and low phosphorus availability modify root architecture. In common bean, the basal roots give rise to a major fraction of the whole root system. Unlike other laterals these roots respond to gravitropic stimulation. Their growth angle determines the proportion of the root length in the shallow layers of the soil. A correlation between ethylene production and basal root angle was found in shallow rooted but not deep-rooted genotypes, indicating that acceleration of ethylene synthesis may account for the change in basal root angle in genotypes demonstrating a plastic response to P availability. Short-time gravitropic response of the tap roots of young bean seedlings was not affected by P level in the nutrient solution. Low phosphorus specifically increases root hair length and root hair density in Arabidopsis. We tested 7 different mutants in ethylene perception and response and in each case, the response to low P was lower than that of the wild-type. The extent of reduction in P response varied among the mutants, but every mutant retained some responsiveness to changes in P concentration. The increase in root hair density was due to the increase in the number of trichoblast cell files under low P and was not mediated by ethylene. Low P did not increase the number of root hairs forming from atrichoblasts. This is in contrast to ethylene treatment, which increased the number of root hairs partly by causing root hairs to form on atrichoblasts. 3) Assess the adaptive value of root architectural plasticity in response to phosphorus availability. A simulation study indicated that genetic variation for root architecture in common bean may be related to adaptation to diverse competitive environments. The fractal dimension of tomato root system was directly correlated with P level.

EIN3 and RSL4 interfere with an MYB–bHLH–WD40 complex to mediate ethylene-induced ectopic root hair formation in Arabidopsis

2021 ◽  
Vol 118 (51) ◽  
pp. e2110004118
Author(s):  
Yuping Qiu ◽  
Ran Tao ◽  
Ying Feng ◽  
Zhina Xiao ◽  
Dan Zhang ◽  
...  
Keyword(s):  
Root Hair ◽  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Root Hairs ◽  
Elongation Factor ◽  
Root Hair Development ◽  
Root Hair Formation ◽  
Hair Development ◽  
Transcriptional Complex ◽  
Hair Formation

The alternating cell specifications of root epidermis to form hair cells or nonhair cells in Arabidopsis are determined by the expression level of GL2, which is activated by an MYB–bHLH–WD40 (WER–GL3–TTG1) transcriptional complex. The phytohormone ethylene (ET) has a unique effect of inducing N-position epidermal cells to form root hairs. However, the molecular mechanisms underlying ET-induced ectopic root hair development remain enigmatic. Here, we show that ET promotes ectopic root hair formation through down-regulation of GL2 expression. ET-activated transcription factors EIN3 and its homolog EIL1 mediate this regulation. Molecular and biochemical analyses further revealed that EIN3 physically interacts with TTG1 and interferes with the interaction between TTG1 and GL3, resulting in reduced activation of GL2 by the WER–GL3–TTG1 complex. Furthermore, we found through genetic analysis that the master regulator of root hair elongation, RSL4, which is directly activated by EIN3, also participates in ET-induced ectopic root hair development. RSL4 negatively regulates the expression of GL2, likely through a mechanism similar to that of EIN3. Therefore, our work reveals that EIN3 may inhibit gene expression by affecting the formation of transcription-activating protein complexes and suggests an unexpected mutual inhibition between the hair elongation factor, RSL4, and the hair specification factor, GL2. Overall, this study provides a molecular framework for the integration of ET signaling and intrinsic root hair development pathway in modulating root epidermal cell specification.

scholarly journals The karrikin signaling regulator SMAX1 controlsLotus japonicusroot and root hair development by suppressing ethylene biosynthesis

2020 ◽  
Vol 117 (35) ◽  
pp. 21757-21765 ◽  
Author(s):  
Samy Carbonnel ◽  
Debatosh Das ◽  
Kartikye Varshney ◽  
Markus C. Kolodziej ◽  
José A. Villaécija-Aguilar ◽  
...  
Keyword(s):  
Root Hair ◽  
Lotus Japonicus ◽  
Root Hairs ◽  
Acc Synthase ◽  
Ethylene Biosynthesis ◽  
Dependent Manner ◽  
Ethylene Signaling ◽  
Root Hair Development ◽  
Hair Development ◽  
Developmental Responses

An evolutionarily ancient plant hormone receptor complex comprising the α/β-fold hydrolase receptor KARRIKIN INSENSITIVE 2 (KAI2) and the F-box protein MORE AXILLARY GROWTH 2 (MAX2) mediates a range of developmental responses to smoke-derived butenolides called karrikins (KARs) and to yet elusive endogenous KAI2 ligands (KLs). Degradation of SUPPRESSOR OF MAX2 1 (SMAX1) after ligand perception is considered to be a key step in KAR/KL signaling. However, molecular events which regulate plant development downstream of SMAX1 removal have not been identified. Here we show thatLotus japonicusSMAX1 is specifically degraded in the presence of KAI2 and MAX2 and plays an important role in regulating root and root hair development.smax1mutants display very short primary roots and elongated root hairs. Their root transcriptome reveals elevated ethylene responses and expression ofACC Synthase 7(ACS7), which encodes a rate-limiting enzyme in ethylene biosynthesis.smax1mutants release increased amounts of ethylene and their root phenotype is rescued by treatment with ethylene biosynthesis and signaling inhibitors. KAR treatment inducesACS7expression in a KAI2-dependent manner and root developmental responses to KAR treatment depend on ethylene signaling. Furthermore, inArabidopsis, KAR-induced root hair elongation depends onACS7. Thus, we reveal a connection between KAR/KL and ethylene signaling in which the KAR/KL signaling module (KAI2–MAX2–SMAX1) regulates the biosynthesis of ethylene to fine-tune root and root hair development, which are important for seedling establishment at the beginning of the plant life cycle.

scholarly journals Lipochito-Oligosaccharide Nodulation Factors Stimulate Cytoplasmic Polarity with Longitudinal Endoplasmic Reticulum and Vesicles at the Tip in Vetch Root Hairs

2000 ◽  
Vol 13 (12) ◽  
pp. 1385-1390 ◽  
Author(s):  
Deborah D. Miller ◽  
Hetty B. Leferink-ten Klooster ◽  
Anne Mie C. Emons
Keyword(s):  
Endoplasmic Reticulum ◽  
Root Hair ◽  
Root Hairs ◽  
Root Hair Development ◽  
Nodulation Factors ◽  
Hair Development ◽  
Nodulation Factor

Vetch root hair development has four stages: bulge, growing, growth terminating, and full-grown hair. In the assay we used, the nodulation factor induced swellings and outgrowths in growth-terminating hairs. Bulges, swellings, and full-grown hairs have transverse endoplasmic reticulum (ER) and no tip-accumulated vesicles. Growing hairs and outgrowths show vesicle accumulation in the tip and longitudinal subapical ER. Bulge walls and walls of swellings appear mottled.

scholarly journals Hormonal regulation of root hair growth and responses to the environment in Arabidopsis

2020 ◽  
Vol 71 (8) ◽  
pp. 2412-2427 ◽  
Author(s):  
Kris Vissenberg ◽  
Naomi Claeijs ◽  
Daria Balcerowicz ◽  
Sébastjen Schoenaers
Keyword(s):  
Root Hair ◽  
Hormonal Regulation ◽  
Hair Growth ◽  
Root Hairs ◽  
Feedback Loops ◽  
Root Hair Development ◽  
Heterogeneous Soil ◽  
Root Hair Growth ◽  
Hair Development ◽  
Signalling Cascade

Abstract The main functions of plant roots are water and nutrient uptake, soil anchorage, and interaction with soil-living biota. Root hairs, single cell tubular extensions of root epidermal cells, facilitate or enhance these functions by drastically enlarging the absorptive surface. Root hair development is constantly adapted to changes in the root’s surroundings, allowing for optimization of root functionality in heterogeneous soil environments. The underlying molecular pathway is the result of a complex interplay between position-dependent signalling and feedback loops. Phytohormone signalling interconnects this root hair signalling cascade with biotic and abiotic changes in the rhizosphere, enabling dynamic hormone-driven changes in root hair growth, density, length, and morphology. This review critically discusses the influence of the major plant hormones on root hair development, and how changes in rhizosphere properties impact on the latter.

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