Anoxia Tolerance in a Root Hair Defective Mutant of Rice

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.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.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.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.

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

Plant and Soil ◽

10.1007/s11104-021-05084-8 ◽

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.

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SEM and fluorescence imaging of callose deposition in root hair tips and suspension cultures of Streptanthus tortuosus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161047 ◽

1990 ◽

Vol 48 (3) ◽

pp. 698-699

Author(s):

K.S. Walters ◽

R.D. Sjolund ◽

K.C. Moore

Keyword(s):

Cell Wall ◽

Root Hair ◽

Cultured Cells ◽

Root Hairs ◽

Callus Cultures ◽

Callose Deposition ◽

Culture Cells ◽

Wall Structures ◽

Ultraviolet Illumination ◽

Callose Formation

Callose, B-1,3-glucan, a component of cell walls, is associated with phloem sieve plates, plasmodesmata, and other cell wall structures that are formed in response to wounding or infection. Callose reacts with aniline blue to form a fluorescent complex that can be recognized in the light microscope with ultraviolet illumination. We have identified callose in cell wall protuberances that are formed spontaneously in suspension-cultured cells of S. tortuosus and in the tips of root hairs formed in sterile callus cultures of S. tortuosus. Callose deposits in root hairs are restricted to root hair tips which appear to be damaged or deformed, while normal root hair tips lack callose deposits. The callose deposits found in suspension culture cells are restricted to regions where unusual outgrowths or protuberances are formed on the cell surfaces, specifically regions that are the sites of new cell wall formation.Callose formation has been shown to be regulated by intracellular calcium levels.

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