The causes for barley root growth retardation in the presence of ammonium and glutamate

Skobeleva, O. V.; Ktitorova, I. N.; Agal’tsov, K. G.

doi:10.1134/s1021443711010195

Cited by 3 publications

(4 citation statements)

References 23 publications

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“…This observation provided grounds to distinguish moderate stress, characterized by the decrease in L p and δD/D, from severe stress typified by the increase in both parameters [7]. A similar reversion of changes in L p and δD/D was also observed while the progressive reduction of root growth under the action of ammo nium and glutamate [11]. Based on these observations, the dynamics of L p and δD/D can be considered as a manifestation of nonspecific changes in physiological condition of growing cells during stress, these changes being caused by accumulation of reactive oxygen spe cies (ROS) and by the increase in cytosolic concentra tions of H + and Ca 2+ ( and ).…”

Section: Introductionsupporting

confidence: 54%

“…While studying root growth under variable condi tions of nitrogen nutrition, we showed that the growth rate is not directly related to L p and δD/D values [11]. The lack of direct relation is also evident from the reversion of L p and δD/D changes during progressive inhibition of root growth (Fig.…”

Section: Possible Causes Of Growth Reduction In Stressed Rootsmentioning

confidence: 80%

“…The fast retardation of root growth in the presence of ammonium might be primarily caused by cytosolic acidification related to metabolic production of pro tons during ammonium nutrition [11]. Figure 4c shows that the progressive acidification of the cytosol in the presence of α naphthyl acetate produced an abrupt decrease in δl after a 14 h period and the increase in L p and δD/D, these changes being charac teristic of severe stress condition.…”

Section: Resultsmentioning

confidence: 97%

“…We proposed previously that both effects could be masked by the sustained high activity of the H + pump under moderate stress. The H + pump operation would create conditions for acid ification and compacting of the apoplast, as well as for blockage by protons of water conducting channels [11]. The H + pump activation under moderate stress is quite likely because it arises from and counteracts the cytosolic acidification.…”

Section: Possible Causes Of L P and δD/d Dynamics Under Severe Stressmentioning

confidence: 99%

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Biophysical parameters as informative tools for elucidating the causes of root growth retardation under stressful conditions

Ktitorova

Skobeleva

Agal’tsov

2011

Russ J Plant Physiol

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The root growth rate in barley (Hordeum vulgare L.) seedlings was measured in parallel with tem poral changes in longitudinal (δl) and transverse (δD/D) cell wall extensibilities and membrane hydraulic conductivity (L p ) in the root extension zone. The root growth rate and biophysical parameters examined were sensitive to UV B irradiation of shoots or roots and to excessive content of ammonium, glutamate, or nickel in the nutrient medium. The root responses to the above treatments were compared with the effects of abscisic acid, salicylate, hydrogen peroxide, diethylstilbestrol, α naphthyl acetate, oryzalin, and ionomycin. The pro gressive reduction of root growth under the action of various stressors was accompanied by typical temporal patterns of the growth zone parameters: the δl extensibility declined monotonically, while δD/D and L p changed nonmonotonically, exhibiting the reversion from the initial decrease to the eventual increase above the control values. The decline of δl indicated that the root growth suppression was mainly due to changes in cell wall mechanical properties caused probably by disorganization of cortical microtubules. It was found that the decline in δD/D and L p was caused primarily by the appearance of oxidative stress, disorders in cyto plasmic H + homeostasis in root cells, and the consequent transient activation of the plasmalemmal H + pump. Conversely, the increase in δD/D and L p upon the abrupt retardation of root growth was presumably caused by the increase in cytoplasmic Ca 2+ content, disassembling of cortical microtubules, and by partial inhibition of the plasmalemmal H + pump. The reversion of δD/D and L p changes upon progressive reduction of root growth can be used as an indicator to distinguish moderate and severe stress conditions in the root growth zone. Furthermore, this reversion indicates the increasing disbalance in the homeostasis of reactive oxygen species, cytosolic Ca 2+ , and cytosolic H + upon severe stress. Abbreviations: CMT-cortical microtubules; D-root diameter; DES-diethylstilbestrol; and -cytosolic concen trations of H + and Ca 2+ ; L p -hydraulic conductivity of the rhizodermal cell membrane; δD/D-transverse extensibility of the root; δl-longitudinal extensibility of the root; Π in -internal osmotic pressure in the root; Π o -osmotic pressure of the medium. H cyt + Ca cyt 2+ RESEARCH PAPERS

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Section: Introductionsupporting

confidence: 54%

Section: Possible Causes Of Growth Reduction In Stressed Rootsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 97%

Section: Possible Causes Of L P and δD/d Dynamics Under Severe Stressmentioning

confidence: 99%

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Biophysical parameters as informative tools for elucidating the causes of root growth retardation under stressful conditions

Ktitorova

Skobeleva

Agal’tsov

2011

Russ J Plant Physiol

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Impact of polyhydroxy fullerene (fullerol or fullerenol) on growth and biophysical characteristics of barley seedlings in favourable and stressful conditions

et al. 2015

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Glutamate signalling in roots

Forde

2013

Journal of Experimental Botany

122

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As a signalling molecule, glutamate is best known for its role as a fast excitatory neurotransmitter in the mammalian nervous system, a role that requires the activity of a family of ionotropic glutamate receptors (iGluRs). The unexpected discovery in 1998 that Arabidopsis thaliana L. possesses a family of iGluR-related (GLR) genes laid the foundations for an assessment of glutamate's potential role as a signalling molecule in plants that is still in progress. Recent advances in elucidating the function of Arabidopsis GLR receptors has revealed similarities with iGluRs in their channel properties, but marked differences in their ligand specificities. The ability of plant GLR receptors to act as amino-acid-gated Ca(2+) channels with a broad agonist profile, combined with their expression throughout the plant, makes them strong candidates for a multiplicity of amino acid signalling roles. Although root growth is inhibited in the presence of a number of amino acids, only glutamate elicits a specific sequence of changes in growth, root tip morphology, and root branching. The recent finding that the MEKK1 gene is a positive regulator of glutamate sensitivity at the root tip has provided genetic evidence for the existence in plants of a glutamate signalling pathway analogous to those found in animals. This short review will discuss the most recent advances in understanding glutamate signalling in roots, considering them in the context of previous work in plants and animals.

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The causes for barley root growth retardation in the presence of ammonium and glutamate

Cited by 3 publications

References 23 publications

Biophysical parameters as informative tools for elucidating the causes of root growth retardation under stressful conditions

Biophysical parameters as informative tools for elucidating the causes of root growth retardation under stressful conditions

Impact of polyhydroxy fullerene (fullerol or fullerenol) on growth and biophysical characteristics of barley seedlings in favourable and stressful conditions

Glutamate signalling in roots

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