scholarly journals Effects of beauvericin on root cell transmembrane electric potential, electrolyte leakage and respiration of maize roots with different susceptibility to Fusarium

2011 ◽  
Vol 52 (No. 11) ◽  
pp. 492-498 ◽  
Author(s):  
J. Pavlovkin ◽  
I. Mistríková ◽  
M. Luxová ◽  
I. Mistrík
Keyword(s):  
Electric Potential ◽  
Electrolyte Leakage ◽  
Cumulative Effect ◽  
Significant Inhibition ◽  
Membrane Potentials ◽  
Root Cell ◽  
Cortical Cells ◽  
Root Cells ◽  
Membrane Conductivity ◽  
Maize Roots

Effect of beauvericin on root cell transmembrane electric potential (E<sub>M</sub>), electrolyte leakage and respiration of roots were studied in two maize cultivars (Zea mays L.) with different susceptibility to this toxigenic metabolite produced by Fusarium. Beauvericin treatment induced rapid and significant depolarisation of membrane potentials of the outer cortical cells of maize roots of tolerant cv. Lucia. The range of depolarisation was dose dependent with maximum depolarisation of 55 mV (55 &plusmn; 7 mV, n = 7) at 200&micro;M beauvericin. In contrast, membrane potentials of beauvericin susceptible cv. Pavla was only slightly depolarised by identical concentrations of beauvericin and the value of depolarisation represented only half of the value of tolerant cv. Lucia (27 &plusmn; 6 mV, n = 8). The values of membrane potentials of root cells of tolerant cv. Lucia were higher (137 &plusmn; 9 mV, n = 26) and more electrogenic (60 &plusmn; 2 mV, n&nbsp;=&nbsp;3) than in susceptible cv. Pavla (125 &plusmn; 7 mV, n = 28), (47 &plusmn; 2 mV, n = 3), respectively. Our results confirmed that 2 h treatment with 50&micro;M beauvericin does not cause irreversible changes in plasma membrane H<sup>+</sup>-ATPase, because fusicoccin, an H<sup>+</sup>-ATPase activator diminished the depolarizing effect of beauvericin on the E<sub>M</sub>. Further experiments revealed beauvericin-induced increase of membrane conductivity in root cells of Pavla but not in root cells of Lucia. Time-coarse experiments showed that 25&micro;M beauvericin induced slight, but significant inhibition of root respiration in both cultivars during the first two hours of treatment, and the inhibition was higher in cv. Lucia than in cv. Pavla. The depolarisation of E<sub>M</sub> in the outer cortical cells of maize roots may be the result of a cumulative effect of beauvericin on ATP supply, activity of H<sup>+</sup>-ATPase and mainly on the permeability of plasmalemma. Increased beauvericin tolerance in maize might be associated with the increased ability of tolerant plant to maintain normal ion fluxes and membrane potentials across the plasmalemma of root cells in the presence of beauvericin.

Short-and long-term effects of cadmium on transmembrane electric potential (E m) in maize roots

Biologia ◽  
2006 ◽  
Vol 61 (1) ◽  
Author(s):  
Ján Pavlovkin ◽  
Miroslava Luxová ◽  
Ingrid Mistríková ◽  
Igor Mistrík
Keyword(s):  
Root Growth ◽  
Electric Potential ◽  
Time Course ◽  
Cumulative Effect ◽  
Significant Inhibition ◽  
Long Term Effects ◽  
Cortical Cells ◽  
Root Cells ◽  
Maize Roots ◽  
Atp Supply

AbstractIn this study, the effects of Cd on root growth, respiration, and transmembrane electric potential (E m) of the outer cortical cells in maize roots treated with various Cd concentrations (from 1 µM to 1 mM) for several hours to one week were studied. The E m values of root cells ranged between −120 and −140 mV and after addition of Cd they were depolarized immediately. The depolarization was concentration-dependent reaching the value of diffusion potential (E D) when the Cd concentration exceeded 100 µM. The values of E D ranged between −65 to −68 mV (−66 ± 1.42 mV). The maximum depolarization of E m was registered approx. 2.5 h after addition of Cd to the perfusion solution and in some cases, partial (Cd > 100 µM) or complete repolarization (Cd < 100 µM) was observed within 8–10 h of Cd treatment. In the time-dependent experiments (0 to 168 h) shortly after the maximum repolarization of E m a continuous concentration-dependent decrease of E m followed at all Cd concentrations. Depolarization of E m was accompanied by both increased electrolyte leakage and inhibition of respiration, especially in the range of 50 µM to 1 mM Cd, with the exception of root cells treated with 1 and 10 µM Cd for 24 and 48 h. Time course analysis of Cd impact on root respiration revealed that at higher Cd concentrations (> 50 µM) the respiration gradually declined (∼ 6 h) and then remained at this lowest level for up to 24 h.All the Cd concentrations used in this experiment induced significant inhibition of root elongation and concentrations higher than 100 µM stopped the root growth within the first day of Cd treatment. Our results suggest that Cd does not cause irreversible changes in the electrogenic plasma membrane H+ ATPase because fusicoccin, an H+ ATPase activator diminished the depolarizing effect of Cd on the E m. The depolarization of E m in the outer cortical cells of maize roots was the result of a cumulative effect of Cd on ATP supply, plasmalemma permeability, and activity of H+ ATPase.

scholarly journals Mathematical Model and Simulation for Nutrient-Plant Interaction Analysis

2020 ◽  
Author(s):  
Byunghyun Ban
Keyword(s):  
Cell Membrane ◽  
Interaction Analysis ◽  
Plant Root ◽  
Gene Expression Pattern ◽  
Root Cell ◽  
Ion Concentration ◽  
Absorption Model ◽  
Membrane Flow ◽  
Root Cells ◽  
Model And Simulation

Differential equation models to understand interaction between plant and nutrient solution are presented. The root cells selectively emit H+ ions with active transport consuming ATPs to establish electrical gradient along the cell membrane. It establishes electrical field with Nernst potential to make positively charged ions outside the cell membrane flow into the root cell. Anion influx is also modulated by H+ ion concentration because plant root cell absorbs negatively charged particles with symport. If an anion collides with H+ cell to make net charge as neutral, at symport channel, it can flow through. In this paper, mathematical models for cation and anion absorption are introduced. Cation absorption model was induced from Ohm's law combined with Goldman's equation. Anion absorption model is similar to chemical reaction rate model. Both models have physiological terms influenced by gene expression pattern, species or phenotypes. Cation model also includes terms for ion's kinetic and electrical properties, growth of plant and interaction between the root and the surroundings. Simulation for 20 different sets of coefficients showed that the physiology-related coefficient has important role on nutrition absorption tendencies of plants.

Differences in the colonization of Pinus banksiana roots by sib-monokaryotic and dikaryotic strains of ectomycorrhizal Laccaria bicolor

1989 ◽  
Vol 67 (6) ◽  
pp. 1717-1726 ◽  
Author(s):  
Ken K. Y. Wong ◽  
Yves Piché ◽  
Diane Montpetit ◽  
Bradley R. Kropp
Keyword(s):  
Pinus Banksiana ◽  
Intraspecific Variability ◽  
Root Cell ◽  
Laccaria Bicolor ◽  
Cortical Cells ◽  
Aseptic Culture ◽  
Hartig Net ◽  
Cell Layers ◽  
The Mean ◽  
Root Surfaces

First-order laterals of Pinus banksiana seedlings were inoculated with variant strains of ectomycorrhizal Laccaria bicolor in an aseptic culture system. Macroscopic observations of 10 fungal strains indicated that 6 are mycorrhizal and 4 are apparently nonmycorrhizal. Furthermore, light microscopic examinations revealed significant intraspecific variation in mycorrhizal structures. The mean mantle thickness, mean mantle density, and mean Hartig net penetration of the six mycorrhizal strains ranged from 2.5 to 13.4 hyphae, 278 to 411 hyphae/mm and 2 to 2.8 root cell layers, respectively. Three of these strains formed fewer macroscopically observable mycorrhizae and developed significantly thinner mantles but their Hartig nets usually separated cortical cells more extensively. Three of the four apparently nonmycorrhizal strains showed infrequent and poor Hartig net development (mean penetration of 0.3 to 0.8 root cell layer), poor surface colonization, and no mantle development. These three strains were better able to colonize long roots. Only one strain could be considered truly nonmycorrhizal because it only colonized root surfaces poorly and never showed mantle or Hartig net formation. The observed intraspecific variability raises questions concerning the determinants of mycorrhiza development and structure.

Cortical colonisation is not an absolute requirement for phosphorus transfer to plants in arbuscular mycorrhizas formed by Scutellospora calospora in a tomato mutant: evidence from physiology and gene expression

2010 ◽  
Vol 37 (12) ◽  
pp. 1132 ◽  
Author(s):  
Maria Manjarrez ◽  
Helle M. Christophersen ◽  
Sally E. Smith ◽  
F. Andrew Smith
Keyword(s):  
Gene Expression ◽  
Arbuscular Mycorrhizas ◽  
Physiological Data ◽  
Cortical Cells ◽  
Root Cells ◽  
Absolute Requirement ◽  
Cell Layers ◽  
Mycorrhizal Colonisation ◽  
Hyphal Coils ◽  
Scutellospora Calospora

Arbuscules in Arum-type arbuscular mycorrhizas (AM), formed intracellularly in root cortical cells, are generally believed to be the most important and defining characteristics of the symbiosis as sites for phosphorus (P) and carbon (C) exchange. We used a Pen + Coi– phenotype (penetration of epidermal and exodermal root cells but not arbuscule formation) formed in rmc (reduced mycorrhizal colonisation) mutant tomato (Lycopersicon esculentum Mill.) by Scutellospora calospora (Nicol. & Gerd.) Walker & Sanders to determine whether the fungus is capable of transferring P from soil to plant and whether there is concurrent upregulation of AM-inducible orthophosphate (Pi) transporter gene expression in the roots. Our physiological data showed that colonisation of outer root cell layers is sufficient for P transfer from S. calospora to tomato. This transfer of P was supported by increased expression of the Pi transporter genes, LePT3 and LePT5, known to be upregulated in AM interactions. We conclude that cortical colonisation and formation of arbuscules or arbusculate hyphal coils is not an absolute prerequisite for P transfer in this symbiosis.

Solute is imported to elongating root cells of barley as a pressure driven-flow of solution

2004 ◽  
Vol 31 (4) ◽  
pp. 391 ◽  
Author(s):  
Nick Gould ◽  
Michael R. Thorpe ◽  
Peter E. H. Minchin ◽  
Jeremy Pritchard ◽  
Philip J. White
Keyword(s):  
Hydrostatic Pressure ◽  
Pressure Difference ◽  
Root Elongation ◽  
Root Cell ◽  
Root Cells ◽  
High K ◽  
K Concentration ◽  
Pressure Driven Flow ◽  
Low K ◽  
Pressure Driven

This work relates solute import to elongating root cells in barley to the water relations of the symplastic pathway under conditions of varied plant K+ status. K+ is a major constituent of phloem sieve element (SE) sap, and as an osmoticum, it is believed to have a role in maintaining SE hydrostatic pressure and thus sap flow from source to sink tissue. The hypothesis that the solute import to elongating root cells is linked to pressure driven flow from the sieve tube is examined.Plants were grown in solutions containing either 0.05 mM (low K) or 2.05 mM (high K) K+ concentration. Solute import to the root elongation zone was estimated from biomass accumulation over time accounting for respiration and root elongation rate. SE sap K+ concentration was measured using X-ray microanalyses and osmotic pressure by picolitre osmometry. SE hydrostatic pressure was measured directly with a pressure probe glued onto an excised aphid stylet. Elongating root cell hydrostatic pressure was measured using a cell pressure probe.The low-K plants had lower SE K+ concentration and SE hydrostatic pressure compared to the high-K plants, but the elongating root cell hydrostatic pressure was similar in both treatments, thus the pressure difference between the SE and elongating root cells was less in the low-K plants compared to the high-K plants.The solute import rate to elongating root cells was lower in the low K plants and the reduction could be accounted for as a pressure driven solute flux, with a reduction both in the pressure difference between root sieve elements and elongating cells, and in the sap concentration.

Silicon improves salinity tolerance and affects ammonia assimilation in maize roots

Biologia ◽  
2014 ◽  
Vol 69 (9) ◽  
Author(s):  
Zuzana Kochanová ◽  
Katarína Jašková ◽  
Barbora Sedláková ◽  
Miroslava Luxová
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Electrolyte Leakage ◽  
Ammonia Assimilation ◽  
Root Growth Inhibition ◽  
Time Range ◽  
Saline Stress ◽  
Protective Effects ◽  
Plant Vigour ◽  
Maize Roots

AbstractThe present study was conducted to evaluate the effect of different salt concentrations (50 and 200 mM NaCl) on growth, permeability properties (electrolyte leakage, cell viability) and activity of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in roots of maize seedlings. Both salt concentrations significantly affected growth and permeability properties of maize seedling roots and this negative effect increased with concentration of salt and duration of experiments. On the other hand salinity induced only small changes in the activities of GS and GDH, usually small increase in the activity was observed. To characterise the possible protective effect of silicon (Si) on maize roots exposed to saline stress, different concentrations of Si were simultaneously applied to both, low (50 mM) and high (200 mM) salt concentrations. Possible protective effects of Si on studied parameters were analysed in time range of 3 days treatment with the most positive effect on salt-induced root growth inhibition at high salt concentration and electrolyte leakage. The results show significant increase in GDH activity under all the tested conditions, although the mechanisms underlying this increase have not been elucidated. The results indicate that silicon may ameliorate the salt-induced root growth inhibition and increase the plant vigour at stressful conditions.

EFFECTS OF CORTICOSTERONE ON ADRENOCORTICOTROPHIN-INDUCED MITOCHONDRIAL DIFFERENTIATION WITH SPECIAL REFERENCE TO 11β-AND 18-HYDROXYLATION

1976 ◽  
Vol 70 (2) ◽  
pp. 215-222 ◽  
Author(s):  
M. SALMENPERÄ ◽  
A. I. KAHRI ◽  
A. SAURE
Keyword(s):  
Significant Inhibition ◽  
Dibutyryl Cyclic Amp ◽  
Adrenocortical Cells ◽  
Cortical Cells ◽  
Foetal Rat ◽  
Rat Adrenals ◽  
Induced Changes ◽  
Regulation Of Growth ◽  
Venous Plasma

SUMMARY The effects of corticosterone in concentrations found in adrenal venous plasma on ACTH-induced changes in cultured cortical cells derived from foetal rat adrenals were studied. Corticosterone at a concentration of 5·7 × 10−5 mol/l completely inhibited mitochondrial differentiation to fasciculate-like morphology. The same cultures revealed significant inhibition of 11β- and 18-hydroxylation compared with cultures treated with ACTH only. This was shown by the reduced formation of corticosterone and 18-OH-deoxycorticosterone (48%, P < 0·001) and simultaneous enhancement of deoxycorticosterone formation (33%, P < 0·05) from added [4-14C]progesterone. Similar inhibition was observed when dibutyryl cyclic AMP replaced ACTH as an inducer of differentiation. Lower concentrations of corticosterone (1·2 × 10−5 and 2·4 × 10−5 mol/l) inhibited ACTH-stimulated formation of corticosterone and 18-OH-deoxycorticosterone from endogenous precursors. The results demonstrate that corticosterone regulates the stage of differentiation in cultured adrenocortical cells. The possible role of corticosterone in the regulation of growth and steroidogenic capacity of the adrenal cortex is discussed.

scholarly journals The contrasting influence of short-term hypoxia on the hydraulic properties of cells and roots of wheat and lupin

2010 ◽  
Vol 37 (3) ◽  
pp. 183 ◽  
Author(s):  
Helen Bramley ◽  
Neil C. Turner ◽  
David W. Turner ◽  
Stephen D. Tyerman
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Hydraulic Properties ◽  
Turgor Pressure ◽  
Lupinus Luteus ◽  
Yellow Lupin ◽  
Cortical Cells ◽  
Crop Species ◽  
Wheat Roots ◽  
Root Cells

Little is known about water flow across intact root cells and roots in response to hypoxia. Responses may be rapid if regulated by aquaporin activity, but only if water crosses membranes. We measured the transport properties of roots and cortical cells of three important crop species in response to hypoxia (0.05 mol O2 m–3): wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and yellow lupin (Lupinus luteus L.). Hypoxia influenced solute transport within minutes of exposure as indicated by increases in root pressure (Pr) and decreases in turgor pressure (Pc), but these effects were only significant in lupins. Re-aeration returned Pr to original levels in yellow lupin, but in narrow-leafed lupin, Pr declined to zero or lower values without recovery even when re-aerated. Hypoxia inhibited hydraulic conductivity of root cortical cells (Lpc) in all three species, but only inhibited hydraulic conductivity of roots (Lpr) in wheat, indicating different pathways for radial water flow across lupin and wheat roots. The inhibition of Lpr of wheat depended on the length of the root, and inhibition of Lpc in the endodermis could account for the changes in Lpr. During re-aeration, aquaporin activity increased in wheat roots causing an overshoot in Lpr. The results of this study demonstrate that the roots of these species not only vary in hydraulic properties but also vary in their sensitivity to the same external O2 concentration.

scholarly journals The Mitotic Index of Cajanus cajan from Kisar Island, in the Southwest of Maluku

2021 ◽  
Vol 13 (2) ◽  
pp. 128-134
Author(s):  
Kristin Sangur ◽  
Alwi Smith ◽  
Meike Tomasoa
Keyword(s):  
Cell Division ◽  
Mitotic Index ◽  
Vegetative Reproduction ◽  
Pigeon Pea ◽  
Root Cell ◽  
Optimum Time ◽  
Root Cells ◽  
Carnoy’S Solution ◽  
Pea Root ◽  
Pea Roots

The mitotic index of the roots of pigeon pea can be the basis for determining the growth of pigeon pea. The purpose of this research was to determine the time of root cell division, to observe the mitotic phases, and to determine the mitotic index of pigeon pea root cells. The preparation of the pigeon pea was carried out for 4 days to grow the roots. The roots were cut off at 08.00, 08.15, and 08.30 WIT (Eastern Indonesian Time). The roots were cut 0.5-1cm. Carnoy’s solution was used as the fixative solution using the Squash technique. The prepared roots were then observed using an Olympus cx-22 microscope and an OptiLab camera with a magnification of 100x40. The data were descriptively analyzed to describe the images of mitotic phases and the mitotic index presentation in the root cells of pigeon pea. The results of this research showed that the cell division of the pigeon pea roots began at 08.00 WIT, which was marked by the presence of a lot of prophase. The next phases that appeared were prometaphase, metaphase, and anaphase which occurred from 08.15 to 08.30 with different numbers. The highest mitotic index occurred at 08.15, when most of the root cells underwent metaphase. This study succeeded in revealing that the optimum time for pigeon pea root cell division is 08.15 WIT. In the future, this research can help pigeon pea farmers in Southwest of Maluku to carry out vegetative reproduction which is closely related to this mitotic study.

Evidence for Anoxic Zones in 2-3 mm Tips of Aerenchymatous Maize Roots Under Low O2 Supply

1995 ◽  
Vol 22 (5) ◽  
pp. 723 ◽  
Author(s):  
J Gibbs ◽  
GD Bruxelle ◽  
W Armstrong ◽  
H Greenway
Keyword(s):  
Fold Increase ◽  
Growth Reduction ◽  
Root Tips ◽  
Cortical Cells ◽  
Aerenchyma Formation ◽  
Metabolic Cooperation ◽  
Primary Roots ◽  
Maize Roots ◽  
O2 Supply ◽  
Anoxic Zones

Root elongation and the production of the end-products of anaerobic catabolism, ethanol, alanine and lactate, were measured in intact maize roots and excised tips exposed to a variety of oxygen regimes. Elongation was retarded by 56 and 44% respectively in intact aerenchymatous primary roots of maize incubated in 0.1% stagnant agar, or exposed to 0.06 mol m-3 external O2 in gas-sparged solution. This growth reduction was accompanied by a 3-5-fold increase in alanine as a percentage of total soluble amino acids in the 0-2 mm root tips. The increase in this value was not in response to ethylene or translocation of alanine from other parts of the root. Moreover, in excised tips exposed to 0.06 mol O2 m-3, net production of ethanol, alanine and lactate occurred. Even so, these root tips continued to elongate at 30% of the rate observed in aerated excised root tips. It appears that adaptation of maize to O2 deficiency may involve a combination of aerenchyma formation and tolerance to anoxia. We suggest that metabolic cooperation, in the form of symplastic transport of energy-rich compounds, might exist between cortical cells receiving adequate oxygen supply and cells in anoxic zones.

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