Intact Roots Research Articles

Oriental Plant Alkanna Orientalis Extracts Effects on Enterococcal Membrane-Associated Properties

The oriental plant Alkanna orientalis tissues extracts have been shown to have antimicrobial activity against a number of gram-positive bacteria, particularly Enterococcus hirae, however mechanisms of this activity is not clear enough.A. orientalis intact root and callus cells extracts influence on E. hirae ATCC9790 whole cells H+/K+ exchange, membrane vesicles accessible SH-groups number and ATPase activity was investigated. It was shown that 50 and 100 μl root extract inhibited H+ release ∼1.27 and ∼1.47 fold and K+ accumulation ∼1.25 and ∼1.36 fold, respectively. Whereas, callus cells extract had a stronger effect on ions fluxes rates. The inhibitor of proton translocating F0F1-ATPase, N,N'-dicyclohexylcarbodiimide (DCCD) - sensitive H+ efflux were observed upon addition of both extracts. The number of SH-groups was lowered ∼1.7 and 2 fold compared with the control in the presence of root and callus cells extracts, respectively. The strongest effect was in the case when these substances were added in the assay medium together with 0.2 mM DCCD. The ATPase activity was also decreased ∼3.1 and 3.5 fold compared with the control in the presence of 100 μl intact root and callus cells extracts, respectively. Maximum inhibition of ATPase activity was detected again when intact root and callus cells extracts were added in the assay medium with 0.2 mM DCCD simultaneously.The results point out that A. orientalis intact root and callus cells extracts can directly affect enterococcal membrane-associated FoF1-ATPase, which can be considered as a target for antimicrobial activity.

Importance of Extraction of DNA from Hair Roots in Forensic Science: A Study

Hair is one of the most frequently found evidences in violent crimes where constant struggle is found as in the cases of murder, kidnapping, sexual assault etc. Forensic Science is solely dependent on the physical evidences found at the scene of crime. With the help of the intact root in the hair sample, DNA can be extracted from the sample which would help to trace the culprit and link him/her with the crime. So, one cannot neglect the importance of hair root in the field of forensic science. One may find either telogen (shed) hair or anagen (pulled) hair in the crime scene. The pulled hair may have intact root and at times root with tissues. These hairs may either be on the clothes of the victim or the crime scene. So, we can say that if the investigation agencies collect these samples properly and examine it properly, it will be possible to link the culprit with the crime scene and the victim.

Inadequate spinal anesthesia in a parturient with Marfan's syndrome due to dural ectasia.

Inadequate spinal anesthesia in a parturient with Marfan's syndrome due to dural ectasia.

Root cortical aerenchyma inhibits radial nutrient transport in maize (Zea mays).

Formation of root cortical aerenchyma (RCA) can be induced by nutrient deficiency. In species adapted to aerobic soil conditions, this response is adaptive by reducing root maintenance requirements, thereby permitting greater soil exploration. One trade-off of RCA formation may be reduced radial transport of nutrients due to reduction in living cortical tissue. To test this hypothesis, radial nutrient transport in intact roots of maize (Zea mays) was investigated in two radiolabelling experiments employing genotypes with contrasting RCA. In the first experiment, time-course dynamics of phosphate loading into the xylem were measured from excised nodal roots that varied in RCA formation. In the second experiment, uptake of phosphate, calcium and sulphate was measured in seminal roots of intact young plants in which variation in RCA was induced by treatments altering ethylene action or genetic differences. In each of three paired genotype comparisons, the rate of phosphate exudation of high-RCA genotypes was significantly less than that of low-RCA genotypes. In the second experiment, radial nutrient transport of phosphate and calcium was negatively correlated with the extent of RCA for some genotypes. The results support the hypothesis that RCA can reduce radial transport of some nutrients in some genotypes, which could be an important trade-off of this trait.

Transpiration integrated model for root ion absorption under salinized condition

Salinization of crop fields is a pressing matter for sustainable agriculture under desertification and is largely attributed to root absorptive functions of the major crops such as maize. The rates of water and ion absorption of intact root system of maize plants were measured under the salinized condition, and the salt absorptive function of maize roots was analyzed by applying different two kinetic models of root ion absorption (i.e. the concentration dependent model and the transpiration integrated model). The absorption rates for salinization ions (Na+, Cl−, Ca2+ and Mg2+) were found to depend on ion mass flow through roots driven by the transpiration, and therefore the transpiration integrated model represented more accurately rates of root ion absorption. The root absorption of salinization ions was characterized quantitatively by two model parameters of Q′max and K′M involved in the transpiration integrated model, which are considered to relate to the potential absorbing power and the ion affinity of transport proteins on root cell membranes, respectively.

Medial Meniscal Root Avulsion: A Biomechanical Comparison of Four Different Repair Constructs.

A locking loop stitch used to repair medial meniscal root avulsions proved significantly stronger in time-zero pullout strength than three other suture consstructs. Medial meniscal root avulsion may lead to a deleterious alteration of medial compartment loading and increased risk of cartilage degeneration. Repair of this injury has been proposed to restore normal biomechanics of the knee. The Purpose of this study was to evaluate the time-zero pullout strength of four different constructs used to repair medial meniscal root avulsions. (1) No meniscal root repair technique will be as biomechanically strong as the intact meniscus. (2) A looped suture construct will resist greater loads than simple sutures. Sixty fresh-frozen cadaveric knees with a mean age of 74 years were used for this study. Each knee was dissected to isolate the attachment of the posterior root of the medial meniscus to the tibial plateau. An Instron machine with custom-designed clamp was used to avulse the intact posterior meniscal root in 12 Control specimens. An additional 48 specimens were tested after transection of the native meniscal root to evaluate the pullout strength of four different repair constructs using #0 FiberWire suture secured to a screw through a trans-tibial tunnel: a Single Suture (n=12), Double Suture (n=12), Loop Stitch (n=12), and a novel Locking Loop Stitch (n=12). Analysis of variance was used to compare pullout strength of all groups with pairwise between-group differences assessed using Tukey’s-adjustment for multiple testing. Repair failure occurred most commonly by suture pullout in 94% of the specimens in the repair groups. For the Controls, failure occurred most commonly at the meniscus-clamp interface. Failure strength was highest for the Control group (mean: 359.5 N + 168 N), followed in descending order by the Locking Loop Stitch (191.4 N + 45.1 N), Loop Stitch (119.6 + 55.0 N), Double Suture (96.2 N + 51.4 N), and Single Suture (58.2 N + 29.6). The Control group was significantly stronger (p<0.0001) than three of the experimental groups (Single Suture, Double Suture, and Loop Stitch) but not the Locking Loop Stitch (p=0.056). The Locking Loop Stitch was significantly stronger than the Single Suture (p<0.0001) and Double Suture (p=0.002) and trended toward significance compared to the Loop Stitch (p=0.06). Age and gender had no effect on pullout strength. The results of this study showed that the novel Locking Loop Stitch provided pullout strength that most closely approximated the strength of the native meniscal root in addition to being significantly stronger than commonly used repair methods. The Locking Loop may be the preferred method for repair of medial meniscal root avulsions.

Breakage of transgenic tobacco roots for monoclonal antibody release in an ultra‐scale down shearing device

Transgenic tobacco roots offer a potential alternative to leaves for monoclonal antibody (MAb) production. A possible method for extraction of MAbs from roots is by homogenization, breaking the roots into fragments to release the antibody. This process was assessed by shearing 10 mm root sections (“roots”) in a 24 mL ultra-scale down shearing device, including an impeller with serrated blade edges, intended to mimic the action of a large-scale homogenizer. Size distributions of the remaining intact roots and root fragments were obtained as a function of shearing time. The data suggest that about 36% of the roots could not be broken under the prevailing conditions and, beyond these unbreakable roots, the fragmentation was approximately first order with respect to intact root number. It was postulated that root breakage in such a high shearing device was due to root-impeller collisions and the particle size data suggest that roots colliding with the impeller were completely fragmented into debris particles of the order of 0.1 mm in length. IgG release normalized to release by grinding appeared to lag behind the number of roots that had fragmented, suggesting that a process of leakage followed fragmentation in the ultra-scale down shearing device.

Influence of vegetation parameters on runoff and sediment characteristics in patterned Artemisia capillaris plots

Vegetation patterns are important in the regulation of earth surface hydrological processes in arid and semi-arid areas. Laboratory-simulated rainfall experiments were used at the State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Yangling, northwestern China, to quantify the effects of Artemisia capillaris patterns on runoff and soil loss. The quantitative relationships between runoff/sediment yield and vegetation parameters were also thoroughly analyzed using the path analysis method for identifying the reduction mechanism of vegetation on soil erosion. A simulated rainfall intensity of 90 mm/h was applied on a control plot without vegetation (C0) and on the other three different vegetation distribution patterns: a checkerboard pattern (CP), a banded pattern perpendicular to the slope direction (BP), and a single long strip parallel to the slope direction (LP). Each patterned plot received two sets of experiments, i.e. intact plants and roots only, respectively. All treatments had three replicates. The results showed that all the three other different patterns (CP, BP and LP) of A. capillaris could effectively reduce the runoff and sediment yield. Compared with C0, the other three intact plant plots had a 12%–25% less runoff and 58%-92% less sediment. Roots contributed more to sediment reduction (46%–70%), whereas shoots contributed more to runoff reduction (57%–81%). BP and CP exhibited preferable controlling effects on soil erosion compared with LP. Path analysis indicated that root length density and plant number were key parameters influencing runoff rate, while root surface area density and root weight density were central indicators affecting sediment rate. The results indicated that an appropriate increase of sowing density has practical significance in conserving soil and water.

Temporal dynamics of nitrogen rhizodeposition in field pea as determined by 15N labeling

Arcand, M. M., Knight, J. D. and Farrell, R. E. 2013. Temporal dynamics of nitrogen rhizodeposition in field pea as determined by 15 N labeling. Can. J. Plant Sci. 93: 941–950. Assessing the contribution of symbiotically fixed N2 to soil from pulse crops necessitates a full accounting of the total crop residue N remaining in the field after seed harvest. Below-ground N, including root and rhizodeposit N, comprises an important component of this total plant N balance – without it the N input to soil is underestimated. Under controlled conditions in a greenhouse, N in intact roots and N rhizodeposition were quantified in field pea (Pisum sativum L.) using the cotton-wick 15N labeling technique. Plants were supplied with 15N on a continuous basis and harvested at the vegetative stage (nine leaves unfolded), flowering, and maturity. As the plants aged, the 15N enrichment in the rhizosphere soil decreased, whereas that in the bulk soil increased, suggesting that N released as root exudates comprised a more important proportion of N rhizodeposition in plants at the early vegetative stage compared with mature plants. In mature plants, N rhizodeposition was comprised predominantly of N associated with root turnover. The contribution of N rhizodeposition recovered in soil to the total plant N balance decreased from 17.8% at the vegetative stage harvest, to 12.3% at flowering, and finally to 7.5% at maturity. However, the total amount of root-derived N released to soil by pea increased with plant development. Below-ground N, including N rhizodeposition and N in intact roots contributed 11.3% to the total plant N balance of mature pea.

A new biotechnological source of rosmarinic acid and surface flavonoids: Hairy root cultures of Dracocephalum kotschyi Boiss

Hairy root induction in Dracocephalum kotschyi Boiss was investigated as a method of producing rosmarinic acid and surface flavonoids, plant secondary metabolites well-known for their antioxidant and anticancer activities. The transformation of D. kotschyi hairy root lines induced by infection with Agrobacterium rhizogenes LBA 9402 was confirmed by PCR detection of rolC and aux1 genes, and their capacity to grow and biosynthesize rosmarinic acid and surface flavonoids was studied. Two types of morphology, typical hairy root and callus-like were observed in the induced root lines. The rolC and aux1 genes were detected in the genome of both morphological types of root lines, although aux1 was more frequently observed in callus-like roots. Our results showed the capacity of the obtained hairy root lines to produce rosmarinic acid and methoxylated flavonoids. Rosmarinic acid content in hairy root lines ranged from 10 to 1500μg/g DW, which at its peak was 15 times higher than in the intact control roots. Surface flavonoids were identified in most hairy root lines, some of which showed a surface flavonoid content higher than the roots of the whole plant but generally lower than the plant leaves.

Abstract 036: The Role Of Spinal Modulation On The Ventricular Electrophysiology In A Porcine Model

Background: Enhanced cardiac sympathetic tone has been associated with ventricular arrhythmias and sudden cardiac death. The spinal cord is an important integrative region of afferent and efferent pathways that participate in cardiovascular regulation. The purpose of this study is to investigate the role of spinal processing of cardiac afferent information on ventricular electrophysiology during cardiac sympathoexcitation. Methods: Female Yorkshire pigs (n=5) underwent surgical exposure of the heart and left stellate ganglion (LSG) through thoractomy as well as the dorsal and ventral roots of the spinal cord through laminectomy. A 56-electrode sock was placed over the ventricles to record epicardial electrograms. Animals underwent LSG stimulation in intact, after dorsal root transaction (DRTx), and followed by ventral root transaction (DVRTx). Activation recovery intervals (ARIs) were measured at each electrode before and during LSG stimulation. Results: With intact roots LSG stimulation resulted in significant global ARI shortening by 12.9% (p&lt;0.05). After DRTx, mean global ARI shortened by 7.2%. LSG stimulation after DRTx and DVRTx resulted in greater ARI shortening compared to LSG stimulation with intact roots (21.5 and 18.4 vs 12.9%, p&lt;0.05, see figure 1 below). ARI shortened more during LSG stimulation after DRTx than that after DVRTx (21.5 vs. 18.4%, p&lt;0.05). Conclusion: Spinal afferent pathways play an inhibitory role in sympathoexcitation of ventricle induced by LSG stimulation. This finding provides insight into the mechanism underlying the beneficial effects of thoracic epidural anesthesia in reducing ventricular arrhythmias.

Fracture Resistance of Root Canals Obturated with Gutta-Percha versus Resilon with Two Different Techniques.

Dentin removal during root canal instrumentation creates a weaker root structure and increases its potential to fracture. The aim of this in vitro experimental study was to compare fracture resistance of teeth filled with gutta-percha, and Resilon using two different techniques. This study was performed on 105 single-canal extracted maxillary incisors. Samples were divided into seven groups of 15 each. Three groups were prepared with K-files; three groups with Race rotary files and in one group no preparation was carried out. Of all samples prepared either manually or with rotary instruments, 15 teeth were obturated using gutta-percha and AH26 sealer, 15 teeth were filled with Resilon and 15 teeth remained unfilled. Loading force to fracture was measured and ANOVA and Tukey tests were used for statistical analysis. No statistically significant differences were observed between different preparation techniques. The intact roots showed significantly greater fracture resistance compared to both instrumented groups (P<0.01). Resilon Group showed significantly higher resistance than gutta-percha Group (P<0.01); however the difference between Resilon and intact teeth was not statistically significant. Accoding to the results of this in vitro study, root canal filling using Resilon may increase the fracture resistance of treated teeth.

Effects of fertilization on Alnus formosana fine root morphological characteristics, biomass and issue content of C, N under A. formosana-Hemarthria compressa compound mode

Aims Our objectives were to: 1) examine fine root biomass, morphological characteristics and content of C and N of Alnus formosana in an A. formosana-Hemarthria compressa composite model in Danling, Sichuan Province, China, 2) examine the effects of fertilization on each order of fine roots, and 3) analyze the relationship between soil nutrients and fine root biomass, architecture and content of C and N. Methods In September 2010, we established two subdistricts, eradicated weeds and planted H. compressa. We fertilized one subdistrict with N-P-K fertilizer in April, June, August and October and did not fertilize the other subdistrict. We excavated soil blocks of 20 cm × 20 cm × 10 cm (height) to sample intact fine root branches of at least the first branch orders. We dissected the intact root branches by orders and measured the diameter, specific root length, biomass, and C and N content of each order. Important findings Fertilization reduced fine-root average diameter in soil surface and increased that in soil subsurface. In fine-root orders 1–5, specific root length increased as root order decreased. Fertilization significantly increased specific root length in fine-root orders 1–3 in soil surface and subsurface (p 0.05). Soil surface total N content of fine roots of 1–5 苗宇等: 施肥对台湾桤木-扁穗牛鞭草复合模式下桤木细根形态特征、生物量及组织碳氮含量的影响 675 doi: 10.3724/SP.J.1258.2013.00070 orders was higher than that in subsurface. Fertilization significantly (p 0.05).

Long-term effects of a lumbosacral ventral root avulsion injury on axotomized motor neurons and avulsed ventral roots in a non-human primate model of cauda equina injury

Here, we have translated from the rat to the non-human primate a unilateral lumbosacral injury as a model for cauda equina injury. In this morphological study, we have investigated retrograde effects of a unilateral L6–S2 ventral root avulsion (VRA) injury as well as the long-term effects of Wallerian degeneration on avulsed ventral roots at 6–10months post-operatively in four adult male rhesus monkeys.Immunohistochemistry for choline acetyl transferase and glial fibrillary acidic protein demonstrated a significant loss of the majority of the axotomized motoneurons in the affected L6–S2 segments and signs of an associated astrocytic glial response within the ventral horn of the L6 and S1 spinal cord segments. Quantitative analysis of the avulsed ventral roots showed that they exhibited normal size and were populated by a normal number of myelinated axons. However, the myelinated axons in the avulsed ventral roots were markedly smaller in caliber compared to the fibers of the intact contralateral ventral roots, which served as controls. Ultrastructural studies confirmed the presence of small myelinated axons and a population of unmyelinated axons within the avulsed roots. In addition, collagen fibers were readily identified within the endoneurium of the avulsed roots.In summary, a lumbosacral VRA injury resulted in retrograde motoneuron loss and astrocytic glial activation in the ventral horn. Surprisingly, the Wallerian degeneration of motor axons in the avulsed ventral roots was followed by a repopulation of the avulsed roots by small myelinated and unmyelinated fibers. We speculate that the small axons may represent sprouting or axonal regeneration by primary afferents or autonomic fibers.

The occurrence of C-shaped root canal in Malaysian population

Background: The recognition of unusual canal’s configurations and variations are essential for successful endodontic diagnosis and treatment. This study was aimed to investigate the occurrence of C- shaped root canal in Malaysian population. Design: This is an in vitro study whereby 241 extracted human first and second molars with intact root were collected from several dental clinics in Malaysia. Materials and Methods: The roots were sectioned at three levels: subpulpal level, 3mm from apical tip and middle level between the first and last level. The appearance of the root canal sections were assessed using stereomicroscope (Leica, Germany) and pictures were taken. Data were analyzed statistically using Fisher’s Exact and Binomial test with p&lt;0.05 indicates statistically significant difference. Results: The occurrence of C- shaped canal among molars collected is 3.73%. Hundred percent of the molars with C- shaped root canal configuration are mandibular molars and 77.8% are belonged to Chinese racial. Conclusion: The findings show that C- shaped root canals do occur among Malaysian people especially Chinese racial. Besides, all the teeth that possess C- shaped root canal configuration are lower molars. Bangladesh Journal of Medical Science Vol. 12 No. 03 July ’13 Page 286-290 DOI: http://dx.doi.org/10.3329/bjms.v12i3.15427

Regeneration of Canada Thistle (Cirsium arvense) from Intact Roots and Root Fragments at Different Soil Depths

In the present field study, the capability of Canada thistle to develop shoots from intact roots and root fragments at different soil depths was studied. The experiments were performed on four sites with high-density Canada thistle, with three or four replications per treatment. At each site, the soil in the plots was removed layer by layer (to 30 or 40 cm, depending on the site), within a 1 by 1-m quadrat, and spread out on a plastic sheet. All roots and other plant parts were removed, and the soil was either replaced without any root material (two sites), or the roots of the thistles were cut into 10-cm-long fragments and replaced into the source holes (two sites). The measured variables were shoot number and biomass. The number of shoots of Canada thistle decreased with increasing depth (P &lt; 0.001) and increased with time. Additionally, the two factors interacted (P &lt; 0.001) such that shoot development was slower from greater depths. Roots from ≤ 20 cm depth produced higher biomasses than did roots from below 20 cm depth. Replacement of root fragments did not affect the amount of biomass produced. It was concluded that the intact root system contributed considerably more to the total biomass produced by Canada thistle than did the root fragments in the upper soil layers.

Medial Meniscal Root Avulsion: A Biomechanical Comparison of Four Different Repair Constructs (SS-67)

Medial Meniscal Root Avulsion: A Biomechanical Comparison of Four Different Repair Constructs (SS-67)

Effects of Root Pruning on Non-Hydraulic Root-Sourced Signal, Drought Tolerance and Water Use Efficiency of Winter Wheat

Two pot experiments were conducted to study the effects of root pruning at the stem elongation stage on non-hydraulic root-sourced signals (nHRS), drought tolerance and water use efficiency of winter wheat (Triticum aestivum). The root pruning significantly reduced the root weight of wheat, but had no effect on root/shoot ratio at the two tested stages. At booting stage, specific root respiration of root pruned plants was significantly higher than those with intact roots (1.06 and 0.94 mmol g−1 s−1, respectively). The soil water content (SWC) at which nHRS for root pruned plants appeared was higher and terminated lower than for intact root plants, the threshold range of nHRS was markedly greater for root pruned plants (61.1-44.6% field water capacity) than for intact root plants (57.9-46.1% field water capacity). At flowering stage, while there was no significant difference in specific root respiration. The SWCs at which nHRS appeared and terminated were both higher for root pruned plants than for intact root plants. The values of chlorophyll fluorescence parameters, i.e., the effective photosystem II quantum yield (ϕPS II), the maximum photochemical efficiency of PS II (Fv/Fm), coefficient of photochemical quenching (qP), and coefficient of non-photochemical quenching (NPQ), in root pruned plants were significantly higher than in intact root plants, 7 d after withholding of water. Root pruned plants had significantly higher water use efficiency (WUE) than intact root plants in well-watered and medium drought soil, but not in severe drought condition. In addition, root pruning had no significant effect on grain yield in well-watered and medium drought soil, but significantly decreased grain yield in severe drought condition. In conclusion, the current study showed that root pruning significantly altered nHRS sensitivity and improved WUE of winter wheat in well-watered and medium drought soil, but lowered drought tolerance of winter wheat in severe drought soil. This suggests a possible direction of drought-resistance breeding and potential agricultural measure to improve WUE of winter wheat under semiarid conditions.

The Socket-Shield Technique: First Histological, Clinical, and Volumetrical Observations after Separation of the Buccal Tooth Segment - A Pilot Study

The "socket-shield technique" has shown its potential in preserving buccal tissues. However, front teeth often have to be extracted due to vertical fractures in buccolingual direction. It has not yet been investigated if the socket-shield technique can only be used with intact roots or also works with a modified shield design referring to vertical fracture lines. The aim of this study was to assess histologically, clinically, and volumetrically the effect of separating the remaining buccal root segment in two pieces before immediate implant placement. Three beagle dogs were selected in the study. The third and fourth premolars on both sides of the upper jaw were hemisected and the clinical crown of the distal root was removed. Then, the implant bed preparation was performed into the distal root so that a buccal segment of healthy tooth structure remained. This segment was then separated in a vertical direction into two pieces and implants placed lingual to it. After 4 months of healing, the specimens were processed for histological diagnosis. In a clinical case, the same technique was applied and impressions taken for volumetric evaluation by digital superimposition. The tooth segments showed healthy periodontal ligament on the buccal side. New bone was visible between implant surface and shield as well as inside the vertical drill line. No osteoclastic remodeling of the coronal part of the buccal plate was observed. The clinical volumetric analysis showed a mean loss of 0.88 mm in labial direction with a maximum of 1.67 mm and a minimum of 0.15 mm. The applied modification seems not to interfere with implant osseointegration and may still preserve the buccal plate. It may offer a feasible treatment option for vertically fractured teeth.

Low-pH and Aluminum Resistance in Arabidopsis Correlates with High Cytosolic Magnesium Content and Increased Magnesium Uptake by Plant Roots

Low-pH stress and Al(3+) toxicity affect root growth in acid soils. It was hypothesized that the capacity of genotypes to maintain Mg(2+) uptake in acidic environments may contribute to low-pH and Al resistance, but explicit evidence is lacking. In this work, an Al-resistant alr104 mutant and two Al-sensitive mutants (als5 and als3) of Arabidopsis thaliana were compared with the wild type (Col-0) for Mg(2+) uptake and intracellular Mg(2+) concentration under low-pH and combined low-pH/Al stresses. Magnesium accumulation in roots was measured in long-term (7 d) experiments. The Mg(2+) fluxes were measured using ion-sensitive microelectrodes at the distal elongation and the mature root zones in short-term (0-60 min) experiments. Intracellular Mg(2+) concentrations were measured in intact root cells at the distal elongation zone using magnesium-specific fluorescent dye and fluorescent lifetime imaging (FLIM) analysis. Under low-pH stress, Arabidopsis mutants als5 and alr104 maintained a higher Mg concentration in roots, and had greater Mg(2+) influx than the wild type and the als3 mutant. Under combined low-pH/Al treatment, Al-resistant genotypes (wild type and alr104) maintained a higher Mg(2+) accumulation, and had a higher Mg(2+) influx and higher intracellular Mg(2+) concentration than Al-sensitive genotypes (als3 and als5). Overall, these results show that increased Mg(2+) uptake correlates with an enhanced capacity of Arabidopsis genotypes to cope with low-pH and combined low-pH/Al stresses.