Radial diffusion transport of water in various zones of maize root and its sensitivity to mercury chloride

Ionenko, I. F.; Анисимов, А. В.

doi:10.1134/s1021443707020100

Cited by 7 publications

(4 citation statements)

References 33 publications

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“…The diffusion time, t d , was chosen to be 300 ms taking into account the following reasons: 1) to exclude the relaxational contribution to the diffusion decay of the apoplastic water, which is characterized by short spin-lattice relaxation times (T 1 < 100 ms) and 2) to reveal the region of hindered diffusion where the contribution of membrane permeability is significant. Moreover, previously it was shown (Ionenko et al 2006, Ionenko andAnisimov 2007) that the inhibition of the diffusion by mercuric chloride was more pronounced at t d > 100 ms.…”

Section: Nmr Measurement Of Water Diffusion Coefficientsmentioning

confidence: 92%

“…The roots of intact maize seedlings were immersed for 15 min in the nutrient solution supplemented with aquaporin inhibitor 0.1 mM HgCl 2 . Inhibitor concentration and the time of incubation were chosen according to Maggio and Joly (1995), Tazawa et al (1997), Zhang and Tyerman (1999) and Ionenko and Anisimov (2007). It was shown that 0.1 mM HgCl 2 does not induce considerable side effects (Ionenko et al 2006), is not toxic (Willmer et al 1999), and does not damage membranes significantly (Wan and Zwiazek 1999).…”

Section: Plant Growth Conditions and Preparation Of Samplesmentioning

confidence: 99%

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Effect of temperature on water transport through aquaporins

Ionenko¹,

Анисимов²,

Dautova³

2010

Biologia plant.

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The mean effective water self-diffusion coefficient in maize root segments under the effect of aquaporin blocker (mercuric chloride, 0.1 mM) was measured using the spin-echo NMR method with pulsed magnetic field gradient within the temperature range from 10 to 35 °С. HgCl 2 caused the reduction in water diffusion by 30 % as compared to the control samples. Temperature dependences of water self-diffusion coefficients showed two linear regions with different values of Q 10 and activation energy, E a . As the temperature reduced from 20 to 10 °С, E a values calculated from the Arrhenius plots were close to those of bulk water (20 ± 3 kJ mol -1 ) and slightly changed for the sample pretreated HgCl 2 . Within the temperature range from 25 to 35 °С the slope of temperature dependences became steeper and E a values were 31 ± 3 kJ mol -1 for the control and 40 ± 4 kJ mol -1 for the treated sample. In the vicinity of 20 o С, the temperature dependence of water diffusion via the mercury-sensitive water channels showed extreme value. In the region, the specific area of the mercury-sensitive aquaporins was 0.004 % of the total cell surface area. The data indicate that water transfer via aquaporins is sensitive to temperature, and the contributions of the transmembrane pathways (aquaporins, lipid bilayer) differ in different temperature ranges.

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Section: Nmr Measurement Of Water Diffusion Coefficientsmentioning

confidence: 92%

Section: Plant Growth Conditions and Preparation Of Samplesmentioning

confidence: 99%

Effect of temperature on water transport through aquaporins

Ionenko¹,

Анисимов²,

Dautova³

2010

Biologia plant.

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“…For the fluorescence and transmission electron microscopy, cross sections at a distance of 0.5 and 1 cm behind the root cap of the nodal roots were used. The distance of 0.5 cm behind the root cap corresponds to the elongation zone of maize root, while the distance of 1 cm behind the cap corresponds to the transition between elongation and differentiationmaturation zone (Ionenko and Anisimov 2007;Evans 1993, 1995). The distance of 1 cm behind the root cap is always shorter than the corresponding distance of the middle of the A sector from the root cap.…”

Section: Samplingmentioning

confidence: 99%

Comparative spatiotemporal analysis of root aerenchyma formation processes in maize due to sulphate, nitrate or phosphate deprivation

et al. 2011

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Nitrate (N), phosphate (P) or sulphate (S) deprivation causes aerenchyma formation in maize (Zea mays L.) nodal roots. The exact mechanisms that trigger the formation of aerenchyma under these circumstances are unclear. We have compared aerenchyma distribution across the nodal roots of first whorl (just emerging in 10-day-old seedlings), which were subject to S, N or P deprivation over a period of 10 days in connection with oxygen consumption, ATP concentration, cellulase and polygalacturonase activity in the whole root. The effect of deprivation on aerenchyma formation was examined using light and electron microscopy, along with in situ detection of calcium and of reactive oxygen species (ROS) by fluorescence microscopy. Aerenchyma was not found in the root base regardless of the deprivation. Programmed cell death (PCD) was observed near the root tip, either within the first two days (-N) or a few days later (-S, -P) of the treatment. Roots at day 6 under all three nutrient-deprived conditions showed signs of PCD 1 cm behind the cap, whereas only N-deprived root cells 0.5 cm behind the cap showed severe ultrastructural alterations, due to advanced PCD. The lower ATP concentration and the higher oxygen consumptions observed at day 2 in N-, P- and S-deprived roots compared to the control indicated that PCD may be triggered by perturbations in energy status of the root. The peaks of cellulase activity located between days 3 (-N) and 6 (-P), along with the respective alterations in polygalacturonase activity, indicated a coordination which preceded aerenchyma formation. ROS and calcium seemed to contribute to PCD initiation, with ROS possessing dual roles as signals and eliminators. All the examined parameters presented both common features and characteristic variations among the deprivations.

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“…Studies regarding the aquaporin mRNA abundance have led to the following conclusions: (1) many aquaporins are highly expressed in the vascular tissues; (2) some tonoplast aquaporins are highly expressed in meristems, where vacuolar biogenesis takes place; (3) aquaporins are highly expressed in the tissues that can experience high water or metabolite flux [39][40][41]. It is therefore of interest to study the expression patterns of AQP isoforms in order to further elucidate their involvement in plant water transport [6,18,19].…”

Section: Aquaporin Gene Expression and Diurnal Fluctuationsmentioning

confidence: 99%

Aquaporin structure–function relationships: Water flow through plant living cells

Zhao

Shao

Chu

2008

Colloids and Surfaces B: Biointerfaces

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Plant aquaporins play an important role in water uptake and movement-an aquaporin that opens and closes a gate that regulates water movement in and out of cells. Some plant aquaporins also play an important role in response to water stress. Since their discovery, advancing knowledge of their structures and properties led to an understanding of the basic features of the water transport mechanism and increased illumination to water relations. Meanwhile, molecular and functional characterization of aquaporins has revealed the significance of their regulation in response to the adverse environments such as salinity and drought. This paper reviews the structure, species diversity, physiology function, regulation of plant aquaporins, and the relations between environmental factors and plant aquaporins. Complete understanding of aquaporin function and regulation is to integrate those mechanisms in time and space and to well regulate the permeation of water across biological membranes under changing environmental and developmental conditions.

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Radial diffusion transport of water in various zones of maize root and its sensitivity to mercury chloride

Cited by 7 publications

References 33 publications

Effect of temperature on water transport through aquaporins

Effect of temperature on water transport through aquaporins

Comparative spatiotemporal analysis of root aerenchyma formation processes in maize due to sulphate, nitrate or phosphate deprivation

Aquaporin structure–function relationships: Water flow through plant living cells

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