Malate Efflux From Root Apices and Tolerance to Aluminium Are Highly Correlated in Wheat

1995 ◽  
Vol 22 (4) ◽  
pp. 531 ◽  
Author(s):  
PR Ryan ◽  
E Delhaize ◽  
PJ Randall
Keyword(s):  
Root Growth ◽  
Triticum Aestivum L ◽  
General Mechanism ◽  
Al Tolerance ◽  
Relative Tolerance ◽  
Relative Root Growth ◽  
Highly Correlated ◽  
Root Apices ◽  
Relative Root ◽  
Sensitive Genotype

Aluminium (Al) can stimulate the efflux of malate and other organic acids from root apices of wheat (Triticum aestivum L.) seedlings. This response has been implicated in a mechanism of Al tolerance since the amount of malate released from an Al-tolerant genotype was 5-10-fold greater than the amount released from a near-isogenic, but Al sensitive, genotype. In the present study, 36 wheat cultivars were screened for Al tolerance and for the amount of malate released from their root apices with a standard A1 treatment. Excised root apices (3.0 mm) were used to measure malate efflux, and the relative tolerance to Al was determined from root growth measurements in 3 and 10μM AlCl3 with 200 μM CaCl2, pH 4.3. There was a significant correlation between relative tolerance of the genotypes to Al and the amount of malate released from their root apices. Growth measurements were also used to investigate the amelioration of Al toxicity by exogenous malate. In the presence of 3 μM Al alone, relative root growth of an Al-sensitive genotype was reduced to 13% of the control. Addition of 10 μM malate to the solution increased relative root growth to 50%, and 20 �M malate completely alleviated the Al-induced inhibition of root growth. The results support the hypothesis that the Al-stimulated efflux of malate from root apices is involved in a general mechanism for Al tolerance in wheat.

Differential tolerance of manganese among cultivars of Triticum aestivum

1989 ◽  
Vol 67 (5) ◽  
pp. 1305-1308 ◽  
Author(s):  
Sheila M. Macfie ◽  
Gregory J. Taylor ◽  
Keith G. Briggs ◽  
John Hoddinott
Keyword(s):  
Triticum Aestivum ◽  
Root Growth ◽  
Solution Culture ◽  
High Yield ◽  
Root Weight ◽  
Al Tolerance ◽  
Control Root ◽  
Relative Root Growth ◽  
Maximum Root ◽  
Relative Root

Thirty cultivars of Triticum aestivum differed in tolerance of manganese (Mn) as determined by relative root growth in solution culture. Based upon a root weight index (RWI = root weight in the presence of 500 μM Mn divided by control root weight), Mn tolerance ranged from 0.08 to 0.88. All Canadian Western Red Spring (CWRS) cultivars tested were Mn sensitive. Cultivars bred for high yield were more Mn tolerant, especially 'Norquay' (RWI = 0.88) which was the only cultivar with a RWI > 0.70. The cultivars 'Norquay' and 'Columbus' were selected as standards for Mn tolerance and Mn sensitivity, respectively. 'Norquay' showed maximum root growth at 100 μM Mn, a concentration which was toxic to 'Columbus', and differential tolerance was maintained up to 1000 μM Mn in solution. Differences between 'Norquay' and 'Columbus', grown in excess Mn, were also observed in the accumulation of biomass with time. In contrast with previous studies, Mn tolerance was positively correlated with Al tolerance (R2 = 32.7, p = 0.001) in the cultivars tested.

scholarly journals Evaluation of Aluminum Sensitivity in Barrel Medic Germplasm

2016 ◽  
Vol 141 (3) ◽  
pp. 249-255 ◽  
Author(s):  
Yawadee Srimake ◽  
Susan C. Miyasaka
Keyword(s):  
Root Growth ◽  
Root Elongation ◽  
Arable Land ◽  
Acid Soils ◽  
Al Tolerance ◽  
Crop Species ◽  
Barrel Medic ◽  
Staining Score ◽  
Relative Root Growth ◽  
Relative Root

Aluminum (Al) toxicity in acid soils is a major constraint to global agricultural production, affecting ≈30% of the world’s arable land area. To study Al tolerance in barrel medic (Medicago truncatula), we assessed responses to excess Al in 91 accessions collected from different geographic regions. Root elongations were used to characterize the sensitivity of each accession. Seedlings were grown in an agarose medium that contained three levels of Al (50, 100, and 200 µm), and root elongation was measured at 72 hours after exposure to Al. The ratio of root elongation in the presence and absence of Al [relative root growth (RRG)] differed among accessions. At 50 µm Al, we observed the greatest range of intraspecific variation. Aluminum sensitivity of 30 accessions was tested further by hematoxylin staining. Relative root growth was regressed linearly against the visual staining score, and a significant, negative, linear relationship was found between RRG at 50 or 100 µm Al and the intensity of staining scores. Twelve selected accessions differing in their resistance were grown in Al-toxic soil to confirm their Al response. Such information could be useful in breeding or selecting for improved Al tolerance in barrel medic, as well as other crop species.

Mechanisms of aluminum tolerance in Triticum aestivum (wheat). V. Nitrogen nutrition, plant-induced pH, and tolerance to aluminum; correlation without causality?

1988 ◽  
Vol 66 (4) ◽  
pp. 694-699 ◽  
Author(s):  
Gregory J. Taylor
Keyword(s):  
Triticum Aestivum ◽  
Root Growth ◽  
Nitrogen Nutrition ◽  
Aluminum Tolerance ◽  
Triticum Aestivum L ◽  
Solution Culture ◽  
Al Tolerance ◽  
Solution Ph ◽  
Relative Tolerance ◽  
Ph Conditions

An aluminum-tolerant cultivar ('Atlas-66') and an aluminum-sensitive cultivar ('Scout-66') of Triticum aestivum L. were grown in solution culture under conditions of varying [Formula: see text] and [Formula: see text] supply with or without 75 μM aluminum. Plants grown with a low [Formula: see text] ratio in solution maintained a higher solution pH than plants grown with a high [Formula: see text] ratio. Although root growth of 'Scout-66' was greater under high [Formula: see text], high solution pH conditions, the relative tolerance of the cultivars to Al was unaffected by the [Formula: see text] ratio and by solution pH. The superior Al tolerance of 'Atlas-66' could not be explained solely by its ability to maintain a high solution pH in mixed nitrogen solutions.

scholarly journals SELEKSI KETAHANAN BEBERAPA KULTIVAR PADI (Oryza sativa L.) LOKAL ASAL KALIMANTAN TIMUR TERHADAP CEKAMAN ALUMINIUM PADA FASE PERKECAMBAHAN

2019 ◽  
Vol 44 (2) ◽  
pp. 178
Author(s):  
Nurul Aini ◽  
Susylowati Susylowati ◽  
Nurhasanah Nurhasanah
Keyword(s):  
Root Growth ◽  
Shoot Growth ◽  
Agricultural Land ◽  
Growth Parameter ◽  
Aluminum Concentration ◽  
Rice Cultivars ◽  
Aluminum Stress ◽  
East Kalimantan ◽  
Relative Root Growth ◽  
Relative Root

Food security and sovereignty can be realized through the expansion of agricultural land to the marginal lands. One type of marginal land is acidie soils with high levels of aluminum (Al) toxicity. An efficient and environmentally friendly approach to utilizeng acidie soils as agricultural land is by using rice varieties which have a high tolerance to aluminum stress on acidie soils. The purpose of this study was to determine the effect of aluminum stress on the growth of the local rice from East Kalimantan and to select the tolerant cultivars against aluminum stress at the germination stage. The study was conducted for three months (May-July 2018), at Laboratory of Biotechnology, Faculty of Agriculture, University of Mulawarman, Samarinda.  This study used a Split Plot Design with three replications. As the main plot was Aluminum stress concentration (A) consisting of 3 levels, namely 0, 250 and 500 ppm of AlCl3 and as subplots were 25 rice genotypes, consisting of 23 local rice cultivars from East Kalimantan (V) and two genotypes as tolerant (Mekongga) and sensitive (IR64) controls. Assessment of aluminum tolerance level was carried out by calculating plant sensitivity index values against aluminum stress based on the Relative Root Growth (RRG) and Relative Shoot Growth (SRG) parameters. Other plant growth parameter data, root and shoot fresh and dry weight, were analyzed using analysis of variance at the test level α = 0.05, and the post-hoch test using Honestly Significant Difference test (HSD). Aluminum stress caused disruption of the East Kalimantan local rice cultivars growth, especially root growth. Aluminum concentration at either 250 ppm or 500 ppm reduced relative root growth and further damage the root system of the rice plants causing roots stunted and thickened. Likewise with shoot growth parameter, there was a relative shoot growth decline due to the aluminum stress on the plants. Two local rice cultivars of East Kalimantan, Pulut Mayang and Pulut Linjuang, were consistently tolerant to aluminum stress either in 250 ppm or 500 ppm of AlCl3; while Kawit, Bentian, Mayas Putih and Ketan putih cultivars were only classified as tolerant at a concentration of 250 ppm aluminum. On the other hand, a control sensitive variety IR64 showed the susceptibility to 250 and 500 ppm aluminum stress.

A COMPARISON OF METHODS OF EVALUATING RUSSIAN WILD RYEGRASS FOR SEEDLING VIGOR

1963 ◽  
Vol 43 (3) ◽  
pp. 307-312 ◽  
Author(s):  
T. Lawrence
Keyword(s):  
Root Growth ◽  
Breeding Program ◽  
Suitable Method ◽  
Seedling Vigor ◽  
Comparison Of Methods ◽  
Glass Tubes ◽  
Relative Root Growth ◽  
Clonal Lines ◽  
Positive Correlations ◽  
Relative Root

Twelve clonal lines of Russian wild ryegrass and the polycross seed from them were used for this study. The lines were evaluated for seedling vigor in the greenhouse, field, and laboratory. Seedling vigor was assessed on the basis of emergence from three depths of seeding, speed of germination, and relative root growth in glass tubes.Seed size of the parental clones and emergence of their progenies from a [Formula: see text]-inch seeding depth showed positive correlations of +0.76 and +0.83 in the greenhouse and field, respectively. Emergence from shallow seedings and relative root growth in glass tubes did not vary sufficiently to provide measured differentiation in seedling vigor. Speed of germination showed some indication that it might be used to determine seedling vigor.Selecting large-seeded lines and subjecting them to deep seeding in either the greenhouse or field is suggested as a suitable method of incorporating seedling vigor into a breeding program.

Effect of aluminium on membrane potential and ion fluxes at the apices of wheat roots

2005 ◽  
Vol 32 (3) ◽  
pp. 199 ◽  
Author(s):  
Tim Wherrett ◽  
Peter R. Ryan ◽  
Emmanuel Delhaize ◽  
Sergey Shabala
Keyword(s):  
Membrane Potential ◽  
Spatial Information ◽  
Triticum Aestivum L ◽  
Ion Fluxes ◽  
Bathing Solution ◽  
Dependent Manner ◽  
Al Tolerance ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Root Apices

Aluminium (Al) tolerance in wheat (Triticum aestivum L.) is associated with the Al-activated efflux of malate and K+ from the root apices. We tested the hypothesis that these Al-activated ion fluxes would induce changes in the membrane potential (Vm) and that these responses would differ between wheat genotypes that differ in Al tolerance. Within minutes of exposing wheat roots to 50 μm AlCl3, a significant depolarisation was measured in the Al-tolerant ET8 genotype but not in a near-isogenic, Al-sensitive genotype, ES8. We investigated the ion movements that may be responsible for these changes in Vm by measuring real-time fluxes of Cl–, H+ and K+ at the root apices of wheat seedlings using the non-invasive microelectrode ion flux estimation (MIFE) technique. Addition of 50 μm AlCl3 to the bathing solution stimulated an increase in K+ efflux and H+ influx in ET8 but not in ES8. The differences between the genotypes were sustained for 24 h and were observed only at the elongating zone and not the meristematic zone. After 24 h Al increased Cl– influx in ET8 but inhibited ES8 influx in a dose-dependent manner. These results provide new temporal and spatial information on the Al-activated ion fluxes from intact wheat plants.

scholarly journals The Response of Duckweed (Lemna minor L.) Roots to Cd and Its Chemical Forms

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yan Xue ◽  
Jin-qin Wang ◽  
Jin Huang ◽  
Feng-ying Li ◽  
Ming Wang
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Root Elongation ◽  
Lemna Minor ◽  
Weibull Model ◽  
Chemical Forms ◽  
Total Antioxidant ◽  
Relative Root Growth ◽  
Relative Root ◽  
Root Growth Rate

The response of duckweed (Lemna minor L.) roots to Cd and its chemical forms was investigated. The relative root growth rate and concentrations of Cd and its different chemical forms in the root, that is, ethanol-extractable (FE-Cd), HCl-extractable (FHCl-Cd), and residual fractions (Fr-Cd), were quantified. Weibull model was used to unravel the regression between the relative root elongation (RRL) with chemical forms of Cd. Parameters assessed catalase (CAT), peroxidases (POD), and superoxide dismutase (SOD), as well as malondialdehyde (MDA) and total antioxidant capacity (A-TOC). Our results show that both the relative root growth rate and relative frond number were affected by Cd concentrations. The chemical forms of Cd were influenced by Cd content in the medium. Relative root elongation (RRL) showed a significant correlation with chemical forms of Cd. Additionally, POD and SOD increased at lower Cd concentrations followed by a decrease at higher Cd concentrations (at more than 5 μM Cd). Moreover, MDA and A-TOC increased and CAT decreased with increasing Cd exposure. Furthermore, CAT showed a significant correlation with FHCl-Cd. Taken together, it can be concluded that the chemical forms of Cd are statistically significant predictors of Cd toxicity to duckweed and to the other similar aquatic plants.

scholarly journals Talking with Strangers: Improving Serianthes Transplant Quality with Interspecific Companions

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1192
Author(s):  
Thomas E. Marler ◽  
Ragan M. Callaway
Keyword(s):  
Root Growth ◽  
Agricultural Systems ◽  
Growth Responses ◽  
Growth And Survival ◽  
Post Transplant ◽  
Or Groups ◽  
Relative Root Growth ◽  
Companion Plants ◽  
Harmful Effects ◽  
Relative Root

Mixtures of species in natural or agricultural systems can increase the performance of individuals or groups relative to monocultures, often through facilitative mechanisms. Mechanisms include root communication by which plants can interrogate the identity of adjacent plants and respond negatively or positively. Alternatively, mixtures of species can ameliorate the harmful effects of soil biota that are pronounced in monocultures, thereby improving plant productivity. Limited investments into roots by shade-grown Serianthes plants in nurseries have been correlated with reduced survival after transplantation to forested habitats. We used companion container cultures in two studies to determine if heterospecific neighbor, or “stranger” roots could experimentally increase the root growth of Serianthes grandiflora plants used as surrogates for the critically endangered Serianthes nelsonii. In one study, native sympatric eudicot and pteridophyte companions increased relative root growth and conspecific companions decreased root growth in comparison to control plants that were grown with no companions. In a second study, the phylogeny of companion plants elicited different root growth responses following the order of congeneric < eudicot = monocot < gymnosperm < pteridophyte. We propose the use of stranger roots that are experimentally maintained in production containers as a passive protocol to improve relative and absolute root growth, leading to improved post-transplant growth and survival of container-grown Serianthes plants.

Root growth and water uptake by wheat during drying of undisturbed and repacked soil in drainage lysimeters

1990 ◽  
Vol 41 (2) ◽  
pp. 253 ◽  
Author(s):  
WS Meyer ◽  
CS Tan ◽  
HD Barrs ◽  
RCG Smith
Keyword(s):  
Root Growth ◽  
Water Uptake ◽  
Root Distribution ◽  
Root Water Uptake ◽  
Soil Drying ◽  
Soil Hydraulic Properties ◽  
Water Fraction ◽  
Neutron Probe ◽  
Relative Root Growth ◽  
Relative Root

The dynamics of root development and water uptake in undisturbed and repacked clay soil were studied during increasing soil water deficit pre- and post-anthesis to find how root distribution, soil type and plant development affect plant available water (PAW). Volumetric water fraction was measured with a neutron probe, while root distribution was measured non-destructively using a series of horizontal perspex observation tubes. Soil modification affected the downward root growth which changed little over time for undisturbed (U) soil (6.7-13.6 mm/d) compared with the repacked (R) soil (7.5-42.9 mm). In the well-watered treatments root distribution was mostly above the 0.55 m depth in U soil, while there was a reasonably uniform vertical distribution in R soil. The rate of root growth during post-anthesis drying was 61% of that during pre-anthesis drying. The specific root water uptake rate (vol./unit root length/time) was linearly related to the relative root growth rate, indicating the importance of root growth in supplying water during soil drying. Estimated PAW values reflected effects of soil hydraulic properties, root distribution and a propensity to grow new roots during soil drying. Differences in grain yield between treatments were thought to result from the effects of different root distributions and the propensity to grow roots during soil drying.

The genomic inheritance of aluminum tolerance in 'Atlas 66' wheat

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 689-693 ◽  
Author(s):  
William A. Berzonsky
Keyword(s):  
Root Growth ◽  
Aluminum Tolerance ◽  
Triticum Aestivum L ◽  
Nuclear Genes ◽  
D Genome ◽  
Hard Red Spring Wheat ◽  
Al Stress ◽  
Soft Red Winter Wheat ◽  
B Genome ◽  
Segregation Ratios

Toxicity to aluminum (Al) limits wheat (Triticum aestivum L. em. Thell.) yields. 'Atlas 66', a soft red winter wheat classified as tolerant (root growth ≥ 0.5 cm after Al stress) to 0.44 mM Al, was hybridized with tetraploid (4x) and hexaploid (6x) 'Canthatch', a hard red spring wheat classified as sensitive (root growth < 0.5 cm after Al stress) to 0.44 mM Al. Progenies produced from these hybridizations were tested for tolerance to 0.44 mM Al in solution to ascertain the number of genes and the genomes of 'Atlas 66', which determine tolerance to aluminum. Tests of 'Atlas 66', 6x-'Canthatch', and the F1's resulting from hybridizations between the parents indicated that dominant, nuclear genes carried by 'Atlas 66' determine tolerance to 0.44 mM Al. Segregation ratios for the F2 significantly differed from ratios expected for a dominant, duplicate genetic mechanism. F1 backcross segregation ratios did not significantly differ from ratios expected for dominant, duplicate nuclear genes for tolerance to aluminum. The expression of genes for tolerance to 0.44 mM Al for 'Atlas 66' appears to be more complex than is predicted by the existence of two dominant genes. A crossing scheme, which involved hybridizing 4x-'Canthatch' with 'Atlas 66', was executed to produce 42-chromosome plants having recombinant A- and B-genome chromosomes and D-genome chromosomes derived exclusively from 'Atlas 66'. Eleven F6 and F7 lines, developed from these plants, were selfed and plants in the F6 generation were backcrossed to 'Atlas 66' and 6x-'Canthatch'. The F6 and F7 lines were subjected to 0.44 mM Al in solution as were the backcrosses. While none of the lines had more than 50% of their seedlings classified as sensitive to Al in the F6 generation, four lines exhibited such a response in the F7 generation. In general, backcrossing the F6 lines to 6x-'Canthatch' increased sensitivity to Al, while backcrossing to 'Atlas 66' increased tolerance. Results suggest that genes for tolerance to Al in 'Atlas 66' wheat are not all located on D-genome chromosomes.Key words: aluminum tolerance, genomic inheritance, Triticum.

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