scholarly journals Does the lack of root hairs alter root system architecture of Zea mays?

2021 ◽  
Author(s):  
Eva Lippold ◽  
Maxime Phalempin ◽  
Steffen Schlüter ◽  
Doris Vetterlein
Keyword(s):  
Zea Mays ◽  
Root System ◽  
Root Hair ◽  
System Architecture ◽  
Volume Fraction ◽  
Root Hairs ◽  
Root System Architecture ◽  
Root Diameter ◽  
Wild Type ◽  
Defective Mutant

Abstract Aims Root hairs are one root trait among many which enables plants to adapt to environmental conditions. How different traits are coordinated and whether some are mutually exclusive is currently poorly understood. Comparing a root hair defective mutant with its corresponding wild-type, we explored if and how the mutant exhibited root growth adaptation strategies and how dependent this was on substrate. Methods Zea mays root hair defective mutant (rth3) and the corresponding wild-type siblings were grown under well-watered conditions on two substrates with contrasting texture and hence nutrient mobility. Root system architecture was investigated over time using repeated X-ray computed tomography. Results There was no plastic adaptation of root system architecture to the lack of root hairs, which resulted in lower uptake of nutrients especially in the substrate with high sorption capacity. The function of the root hairs for anchoring did not result in different root length density profiles between genotypes. Both maize genotypes showed a marked response to substrate. This was well reflected in the spatiotemporal development of rhizosphere volume fraction but especially in the highly significant response of root diameter to substrate, irrespective of genotype. Conclusions The most salient root plasticity trait was root diameter in response to substrate. Coping mechanisms for missing root hairs were limited to a shift in root-shoot ratio in loam. Further experiments are required, to elucidate whether observed differences can be explained by mechanical properties beyond mechanical impedance, root or microbiome ethylene production or differences in diffusion processes within the root or the rhizosphere.

Does the lack of root hairs alter root system architecture of Zea mays?

2021 ◽  
Author(s):  
Steffen Schlüter ◽  
Eva Lippold ◽  
Maxime Phalempin ◽  
Doris Vetterlein
Keyword(s):  
Zea Mays ◽  
Root System ◽  
Root Hair ◽  
System Architecture ◽  
Volume Fraction ◽  
Root Hairs ◽  
Root System Architecture ◽  
Root Diameter ◽  
Wild Type ◽  
Defective Mutant

<p>Root hairs are one root trait among many which enables plants to adapt to environmental conditions. How different traits are coordinated and whether some are mutually exclusive is currently poorly understood. Comparing a root hair defective mutant with its corresponding wild-type we explored if and how the mutant exhibited root growth adaption strategies and as to how far this depended on the substrate.</p><p>Zea mays root hair defective mutant (rth3) and the corresponding wild-type siblings were grown on two substrates with contrasting texture and hence nutrient mobility. Root system architecture was investigated over time using repeated X-ray computed tomography.</p><p>There was no plastic adaption of root system architecture to the lack of root hairs, which resulted in lower uptake in particular in the substrate with low P mobility. The function of the root hairs for anchoring did not result in different depth profiles of the root length density between genotypes. Both maize genotypes showed a marked response to substrate. This was well reflected in the spatiotemporal development of rhizosphere volume fraction but especially in the strong response of root diameter to substrate, irrespective of genotype.</p><p>The most salient root plasticity trait was root diameter in response to substrate, whereas coping mechanisms for missing root hairs were less evident. Further experiments are required to elucidate whether observed differences can be explained by mechanical properties beyond mechanical impedance, root or microbiome ethylene production or differences in diffusion processes within the root or the rhizosphere.</p>

scholarly journals Genotypic diversity and plasticity of root system architecture to nitrogen availability in oilseed rape

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250966
Author(s):  
Christophe Lecarpentier ◽  
Loïc Pagès ◽  
Céline Richard-Molard
Keyword(s):  
Root System ◽  
Oilseed Rape ◽  
System Architecture ◽  
Lateral Root ◽  
Nitrogen Availability ◽  
Root System Architecture ◽  
Root Diameter ◽  
Root Density ◽  
Model Parameters ◽  
New Varieties

In the emerging new agricultural context, a drastic reduction in fertilizer usage is required. A promising way to maintain high crop yields while reducing fertilizer inputs is to breed new varieties with optimized root system architecture (RSA), designed to reach soil resources more efficiently. This relies on identifying key traits that underlie genotypic variability and plasticity of RSA in response to nutrient availability. The aim of our study was to characterize the RSA plasticity in response to nitrogen limitation of a set of contrasted oilseed rape genotypes, by using the ArchiSimple model parameters as screening traits. Eight accessions of Brassica napus were grown in long tubes in the greenhouse, under two contrasting levels of nitrogen availability. After plant excavation, roots were scanned at high resolution. Six RSA traits relative to root diameter, elongation rate and branching were measured, as well as nine growth and biomass allocation traits. The plasticity of each trait to nitrogen availability was estimated. Nitrogen-limited plants were characterized by a strong reduction in total biomass and leaf area. Even if the architecture traits were shown to be less plastic than allocation traits, significant nitrogen and genotype effects were highlighted on each RSA trait, except the root minimal diameter. Thus, the RSA of nitrogen-limited plants was primarily characterised by a reduced lateral root density, a smaller primary root diameter, associated with a stronger root dominance. Among the RSA traits measured, the inter-branch distance showed the highest plasticity with a level of 70%, in the same range as the most plastic allocation traits. This work suggests that lateral root density plays the key role in the adaptation of the root system to nitrogen availability and highlights inter-branch distance as a major target trait for breeding new varieties, better adapted to low input systems.

Potassium transporter TRH1/KUP4 contributes to distinct auxin-mediated root system architecture responses

2021 ◽  
Author(s):  
Dimitris Templalexis ◽  
Dikran Tsitsekian ◽  
Chen Liu ◽  
Gerasimos Daras ◽  
Jan Šimura ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Root System ◽  
Root Hair ◽  
System Architecture ◽  
Auxin Transport ◽  
Root System Architecture ◽  
Growth Responses ◽  
Specific Expression ◽  
Peripheral Cell ◽  
Root Gravitropism

Abstract In plants, auxin transport and development are tightly coupled, just as hormone and growth responses are intimately linked in multicellular systems. Here we provide insights into uncoupling this tight control by specifically targeting the expression of TINY ROOT HAIR 1 (TRH1), a member of plant HAK/KUP/KT transporters that facilitate potassium uptake by co-transporting protons, in Arabidopsis root cell files. Use of this system pinpointed specific root developmental responses to acropetal versus basipetal auxin transport. Loss of TRH1 function shows tiny root hairs and defective root gravitropism, associated with auxin imbalance in the root apex. Cell file-specific expression of TRH1 in the central cylinder rescued trh1 root agravitropism, whereas positional TRH1 expression in peripheral cell layers, including epidermis and cortex, restored trh1 root hair defects. Applying a systems-level approach, the role of RAP2.11 and RSL5 transcription factors in root hair development was verified. Furthermore, ERF53 and WRKY51 transcription factors were overrepresented upon restoration of root gravitropism supporting involvement in gravitropic control. Auxin has a central role in shaping root system architecture by regulating multiple developmental processes. We reveal that TRH1 jointly modulates intracellular ionic gradients and cell-to-cell polar auxin transport to drive root epidermal cell differentiation and gravitropic response. Our results indicate the developmental importance of HAK/KUP/KT proton-coupled K+ transporters.

Mapping QTLs for root system architecture of maize (Zea mays L.) in the field at different developmental stages

2012 ◽  
Vol 125 (6) ◽  
pp. 1313-1324 ◽  
Author(s):  
Hongguang Cai ◽  
Fanjun Chen ◽  
Guohua Mi ◽  
Fusuo Zhang ◽  
Hans Peter Maurer ◽  
...  
Keyword(s):  
Zea Mays ◽  
Root System ◽  
System Architecture ◽  
Zea Mays L ◽  
Developmental Stages ◽  
Root System Architecture

scholarly journals Phosphorus Uptake and Growth of Wild-Type Barley and Its Root-Hairless Mutant Cultured in Buffered-and Non-Buffered-P Solutions

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1556
Author(s):  
Yucong Xie ◽  
Bala Rathinasabapathi ◽  
Bruce Schaffer ◽  
Rao Mylavarapu ◽  
Guodong Liu
Keyword(s):  
Root System ◽  
Root Hair ◽  
Root Hairs ◽  
P Uptake ◽  
The Other ◽  
Genotypic Differences ◽  
Wild Type ◽  
Split Root ◽  
Split Root System ◽  
Plant P Uptake

Root hairs play an important role in phosphorus (P) nutrition of plants. To better understand the relationship between root hairs and P acquisition efficiency (PAE) in barley, experiments were conducted with the wild-type barley (cv. ’Pallas’) and its root-hairless mutant (brb). A hydroponic split-root system was used to supply P as Ca3(PO4)2 (tri-calcium phosphate, TCP) to one-half and other nutrients to the other half of the root system. Using TCP as a sole P source can simulate a soil solution with buffered low P concentration in hydroponics to induce prolific root hair growth. Root morphology, plant growth, and P uptake efficiency were measured with 50 mg L−1 TCP supplied to the roots in the split-root system and 0, 35, or 1000 μM NaH2PO4 in a non-split-root hydroponic system. The wild-type plants developed root hairs, but they did not contribute to the significant genotypic differences in the P uptake rate when a soluble P source was supplied in the non-split root system, indicating that root hair formation does not contribute to P uptake in a non-split root solution. On the other hand, when grown in a split-root system with one-half of the roots supplied with TCP, the wild-type showed 1.25-fold greater P uptake than the root hairless mutant. This study provides evidence that root hairs play an essential role in plant P uptake when P bioavailability is limited in the root zone.

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