Apoplastic transport across young maize roots: effect of the exodermis

Zimmermann, Hilde Monika; Steudle, Ernst

doi:10.1007/s004250050368

Cited by 162 publications

(147 citation statements)

References 47 publications

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“…This supports the literature and establishes that the exodermal Casparian bands in mycorrhizal roots have a similarly low permeability to those of nonmycorrhizal root systems and to the tight junctions of animal cells (Madara, 1988). The finding that the Casparian bands of the exodermis are a barrier to both PTS and La$ + , contrasts with the findings of Zimmermann & Steudle (1998) that the exodermis of corn roots allows PTS leakage. It is consistent with their suggestion that the leakage of PTS into the stele which they observed might be via sites of emergence of lateral roots which breach the exodermis.…”

Section: supporting

confidence: 84%

“…Most evidence from the literature suggests that the Casparian bands in the exodermis of nonmycorrhizal roots are impermeable to ions, although views differ on their permeability to water (Peterson, 1987 ;Peterson et al, 1993 ;Canny & Huang, 1994 ;Peterson & Cholewa, 1998 ;Steudle & Peterson, 1998 ;Zimmermann & Steudle, 1998). It has been shown here that the exodermal Casparian bands are a barrier to penetration of both tracers into the cortex of all the mycorrhizas, regardless of the degree of permeation of PTS or La into the sheath.…”

Section: mentioning

confidence: 61%

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Apoplasmic barriers and their significance in the exodermis and sheath of Eucalyptus pilularis–Pisolithus tinctorius ectomycorrhizas

et al. 2000

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The apoplasmic permeability of ectomycorrhizal roots of intact Eucalyptus pilularis seedlings infected with Pisolithus tinctorius on aseptic agar plates was examined using the nonbinding fluorochrome 8-hydroxypyrene-1,3,6-trisulphonate and lanthanum ions in conjunction with anhydrous freeze substitution and dry sectioning. Most mycorrhizas formed in the air above the agar surface, and in these the sheath rapidly became nonwettable and impermeable to the fluorochrome but was nevertheless permeable to lanthanum ions. In a few mycorrhizas which developed in contact with the agar the sheath remained permeable to both tracers when fully developed. This increased hydrophobicity of the sheath in mycorrhizas in the air above the agar surface might be explained by deposition of hydrophobins, but nevertheless it still allows an apoplasmic pathway for radial movement of ions. Regardless of their sheath permeation both apoplasmic tracers were always found throughout the Hartig net and were arrested at the Casparian bands and suberin lamellae of the exodermis. It is concluded that the fluorochrome must have moved longitudinally along the Hartig net which is a region of higher permeability than the sheath. Casparian bands in the exodermis of ectomycorrhizal roots have similar properties to those in nonmycorrhizal roots in excluding solutes and their exclusion of lanthanum ions indicates that they are not permeable to ions. The data do not support the concept of a totally sealed apoplasmic exchange compartment, but the differential permeability suggests that the sheath might allow radial transfer of ions but block loss of sugars and organic molecules of similar size.

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Section: supporting

confidence: 84%

Section: mentioning

confidence: 61%

Apoplasmic barriers and their significance in the exodermis and sheath of Eucalyptus pilularis–Pisolithus tinctorius ectomycorrhizas

et al. 2000

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“…An asterisk indicates significant difference from the control value of 100% (P , 0.05, using the Student's t test). and Steudle (1998) found some apoplastic water flow under osmotic conditions. Therefore, the two paths contribute to water transport at the same time, but their relative contribution depends on the environmental conditions and one of the two paths may predominate (for review, see Steudle, 2000;Javot and Maurel, 2002).…”

Section: Discussionmentioning

confidence: 94%

The Role of Aquaporins and Membrane Damage in Chilling and Hydrogen Peroxide Induced Changes in the Hydraulic Conductance of Maize Roots

et al. 2005

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When chilling-sensitive plants are chilled, root hydraulic conductance (L o ) declines precipitously; L o also declines in chillingtolerant plants, but it subsequently recovers, whereas in chilling-sensitive plants it does not. As a result, the chilling-sensitive plants dry out and may die. Using a chilling-sensitive and a chilling-tolerant maize genotype we investigated the effect of chilling on L o , and its relationship to osmotic water permeability of isolated root cortex protoplasts, aquaporin gene expression, aquaporin abundance, and aquaporin phosphorylation, hydrogen peroxide (H 2 O 2 ) accumulation in the roots and electrolyte leakage from the roots. Because chilling can cause H 2 O 2 accumulation we also determined the effects of a short H 2 O 2 treatment of the roots and examined the same parameters. We conclude from these studies that the recovery of L o during chilling in the chilling-tolerant genotype is made possible by avoiding or repairing membrane damage and by a greater abundance and/or activity of aquaporins. The same changes in aquaporins take place in the chilling-sensitive genotype, but we postulate that membrane damage prevents the L o recovery. It appears that the aquaporin response is necessary but not sufficient to respond to chilling injury. The plant must also be able to avoid the oxidative damage that accompanies chilling.Many crop species such as maize (Zea mays) that originate in tropical regions are sensitive to low temperatures and grow poorly after exposure to a cold period (Miedema, 1982). Below 12°C to 14°C, maize seedlings are damaged as a result of leaf dehydration and an inhibition of photosynthesis. Such damage may result in the plant's death (Miedema, 1982). With the wide utilization in temperate climates of crops of tropical origin, the adverse effect of chilling is an important agricultural problem the physiological basis of which can be elucidated. Cold-tolerant species increase their root hydraulic conductance (L o ) during low temperature periods (Fennell and Markhart, 1998;Bigot and Boucaud, 2000), and the same phenomenon has been observed in a chilling-tolerant genotype of maize (Aroca et al., 2001b(Aroca et al., , 2003b. The water deficit in the aerial parts of a chilling-sensitive maize genotype is caused in part by low temperature inhibition of L o (Aroca et al., 2001b(Aroca et al., , 2003b. The recovery of L o in cold-tolerant plants may be associated with an increase in the activity or the abundance of aquaporins in the plasma membranes of root cells. On the other hand, the opposite may happen in cold-sensitive species: aquaporins may be down-regulated or inactivated (Aroca et al., 2001b;Sanders and Markhart, 2001;). Lee et al. (2004b) recently showed that in cucumber (Cucumis sativus), a cold sensitive species, a brief exposure to low temperature reduces root pressure, hydraulic conductivity, and active nutrient transport. These authors also postulated that changes in the activity of aquaporins underlie the changes in hydraulic conductivity.Response to cold,...

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“…This value is not significantly different from those measured for rice (Ranathunge et al, 2003). Two to ten times higher values were reported for maize (Zimmermann and Steudle, 1998). In parallel, osmotic pressure gradients can be used for measuring the symplastic flow of water.…”

Section: Physiological Functions Of Diffusion Barriers In Rootsmentioning

confidence: 87%

Apoplastic Diffusion Barriers in Arabidopsis

Nawrath

Schreiber

Franke

et al. 2013

The Arabidopsis Book

131

143

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During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ-and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented.

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Apoplastic transport across young maize roots: effect of the exodermis

Cited by 162 publications

References 47 publications

Apoplasmic barriers and their significance in the exodermis and sheath of Eucalyptus pilularis–Pisolithus tinctorius ectomycorrhizas

Apoplasmic barriers and their significance in the exodermis and sheath of Eucalyptus pilularis–Pisolithus tinctorius ectomycorrhizas

The Role of Aquaporins and Membrane Damage in Chilling and Hydrogen Peroxide Induced Changes in the Hydraulic Conductance of Maize Roots

Apoplastic Diffusion Barriers in Arabidopsis

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