Evaluation of copper, nickel, and zinc tolerances in four grass species

1985 ◽  
Vol 63 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Wilfried E. Rauser ◽  
E. Keith Winterhalder

Clones of Agrostis gigantea, Deschampsia caespitosa, Hordeum jubatuin, and Poa compressa were evaluated for their tolerance with respect to copper, nickel, and zinc. Most of the plants originated from acidic, copper- and nickel-contaminated soils near Sudbury, Ont. Metal tolerance was assayed by measuring all of the adventitious roots growing from tillers but excluding lateral roots. Tolerance of copper, nickel, and zinc was evident in the four clones of D. caespitosa originating from Sudbury. One clone of A. gigantea originating from a roast bed showed tolerance of copper, while none showed tolerance of cither nickel or zinc. One clone of P. compressa from Sudbury indicated increased tolerance of copper and nickel, yet its root growth was inhibited at lower zinc concentrations than that of a companion clone from Sudbury and a control. The H. jubatum plants showed no tolerance of any of the metals. Copper was most toxic to all of the species, followed by nickel and then zinc.

1995 ◽  
Vol 73 (5) ◽  
pp. 766-775 ◽  
Author(s):  
Daniel J. Archambault ◽  
Keith Winterhalder

Acid, metal-contaminated soils are frequently colonized by plant species that have evolved tolerance to metals. Agrostis scabra (tickle grass) grows at several such sites in the Sudbury area. To test whether these populations were tolerant to metals, three experiments were performed. A hydroponic root growth experiment, in which clonal ramets from contaminated and uncontaminated sites were grown in metal-amended nutrient solutions, showed that plants from the Sudbury area had greater tolerance indices than those from outside Sudbury. A seed-based hydroponic experiment, where seeds were germinated in metal solutions, showed that metal-tolerance indices calculated from root growth were mostly greater for populations from Sudbury but that leaf growth was not a good indicator of metal tolerance. A seed-based soil-bioassay experiment, in which seeds were germinated on soils covered with filter paper, showed that seeds from contaminated sites performed better on contaminated soil and a 50:50 soil mixture (contaminated–uncontaminated) than those from uncontaminated sites. Populations of A. scabra growing on contaminated soils in the Sudbury area therefore appear to have been selected for metal tolerance. Ecological aspects of metal tolerance and the possible role of A. scabra in the revegetation of the Sudbury area are discussed. Key words: Agrostis scabra, tolerance, metals, acid soil, contamination.


1970 ◽  
Vol 39 (2) ◽  
pp. 241-243 ◽  
Author(s):  
M Rafiqul Islam ◽  
Abdul Hamid ◽  
Quzi Andul Khaliq ◽  
M Moynul Haque ◽  
Jalal Uddin Ahmed ◽  
...  

Two mungbean (Vigna radiata (L.) Wilczek) genotypes (GK48 - flood tolerant and BARImug5- flood susceptible) were flooded at vegetative and flowering stages for 5 and 10 days, respectively. Flooding damaged the lateral roots of GK48 wholly, but it recovered quickly by forming numerous adventitious roots. Flooding significantly reduced photosynthetic rate (Pn) and leaf water potential (Ψ1) in both the genotypes but GK48 tended to regain Pn and Ψ1 during postflooding phase. It appeared that GK48 withstands flooding to a great extent. Key words: Water potential; Mungbean; Root growth; Photosynthesis DOI: 10.3329/bjb.v39i2.7487 Bangladesh J. Bot. 39(2): 241-243, 2010 (December)


1995 ◽  
Vol 120 (2) ◽  
pp. 211-216 ◽  
Author(s):  
J. Roger Harris ◽  
Nina L. Bassuk ◽  
Richard W. Zobel ◽  
Thomas H. Whitlow

The objectives of this study were to determine root and shoot growth periodicity for established Fraxinus pennsylvanica Marsh. (green ash), Quercus coccinea Muenchh. (scarlet oak), Corylus colurna L. (Turkish hazelnut), and Syringa reticulata (Blume) Hara `Ivory Silk' (tree lilac) trees and to evaluate three methods of root growth periodicity measurement. Two methods were evaluated using a rhizotron. One method measured the extension rate (RE) ofindividual roots, and the second method measured change in root length (RL) against an observation grid. A third method, using periodic counts of new roots present on minirhizotrons (MR), was also evaluated. RE showed the least variability among individual trees. Shoot growth began before or simultaneously with the beginning of root growth for all species with all root growth measurement methods. All species had concurrent shoot and root growth, and no distinct alternating growth patterns were evident when root growth was measured by RE. Alternating root and shoot growth was evident, however, when root growth was measured by RL and MR. RE measured extension rate of larger diameter lateral roots, RL measured increase in root length of all diameter lateral roots and MR measured new root count of all sizes of lateral and vertical roots. Root growth periodicity patterns differed with the measurement method and the types of roots measured.


2010 ◽  
Vol 34 (3) ◽  
pp. 444-456 ◽  
Author(s):  
REBECCA E. HALING ◽  
RICHARD J. SIMPSON ◽  
RICHARD A. CULVENOR ◽  
HANS LAMBERS ◽  
ALAN E. RICHARDSON

Plants ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1722
Author(s):  
Lidiya Vysotskaya ◽  
Guzel Akhiyarova ◽  
Arina Feoktistova ◽  
Zarina Akhtyamova ◽  
Alla Korobova ◽  
...  

Although changes in root architecture in response to the environment can optimize mineral and water nutrient uptake, mechanisms regulating these changes are not well-understood. We investigated whether P deprivation effects on root development are mediated by abscisic acid (ABA) and its interactions with other hormones. The ABA-deficient barley mutant Az34 and its wild-type (WT) were grown in P-deprived and P-replete conditions, and hormones were measured in whole roots and root tips. Although P deprivation decreased growth in shoot mass similarly in both genotypes, only the WT increased primary root length and number of lateral roots. The effect was accompanied by ABA accumulation in root tips, a response not seen in Az34. Increased ABA in P-deprived WT was accompanied by decreased concentrations of cytokinin, an inhibitor of root extension. Furthermore, P-deficiency in the WT increased auxin concentration in whole root systems in association with increased root branching. In the ABA-deficient mutant, P-starvation failed to stimulate root elongation or promote branching, and there was no decline in cytokinin and no increase in auxin. The results demonstrate ABA’s ability to mediate in root growth responses to P starvation in barley, an effect linked to its effects on cytokinin and auxin concentrations.


2019 ◽  
Vol 20 (20) ◽  
pp. 5144
Author(s):  
Huwei Sun ◽  
Xiaoli Guo ◽  
Fugui Xu ◽  
Daxia Wu ◽  
Xuhong Zhang ◽  
...  

The response of root architecture to phosphate (P) deficiency is critical in plant growth and development. Auxin is a key regulator of plant root growth in response to P deficiency, but the underlying mechanisms are unclear. In this study, phenotypic and genetic analyses were undertaken to explore the role of OsPIN2, an auxin efflux transporter, in regulating the growth and development of rice roots under normal nutrition condition (control) and low-phosphate condition (LP). Higher expression of OsPIN2 was observed in rice plants under LP compared to the control. Meanwhile, the auxin levels of roots were increased under LP relative to control condition in wild-type (WT) plants. Compared to WT plants, two overexpression (OE) lines had higher auxin levels in the roots under control and LP. LP led to increased seminal roots (SRs) length and the root hairs (RHs) density, but decreased lateral roots (LRs) density in WT plants. However, overexpression of OsPIN2 caused a loss of sensitivity in the root response to P deficiency. The OE lines had a shorter SR length, lower LR density, and greater RH density than WT plants under control. However, the LR and RH densities in the OE lines were similar to those in WT plants under LP. Compared to WT plants, overexpression of OsPIN2 had a shorter root length through decreased root cell elongation under control and LP. Surprisingly, overexpression of OsPIN2 might increase auxin distribution in epidermis of root, resulting in greater RH formation but less LR development in OE plants than in WT plants in the control condition but levels similar of these under LP. These results suggest that higher OsPIN2 expression regulates rice root growth and development maybe by changing auxin distribution in roots under LP condition.


Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 364-368 ◽  
Author(s):  
P. L. Orwick ◽  
M. M. Schreiber

We studied the early root growth of fourSetariataxa: giant foxtail (Setaria faberiHerrm.), giant green foxtail [Setaria viridisvar.major(Gaud.) Posp.], robust white foxtail (Setaria viridisvar.robusta-albaSchreiber), robust purple foxtail (Setaria viridisvar.robusta-purpureaSchreiber). Growth studies in controlled environments showed significant differences in root elongation among the taxa at three photoperiods. Seminal root lengths after 4 days followed the order presented for selectivity and metabolism of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] and propazine [2-chloro-4,6-bis(isopropylamino)-s-triazine] (robust white foxtail > giant green foxtail = robust purple foxtail > giant foxtail). Giant foxtail had the greatest root diameter, resulting in the greatest surface area and volume when lengths were equated. The order of seminal root lengths or diameters changed little after 7 days. Robust white foxtail had the most and longest first order lateral roots. Diameter of first order laterals showed giant foxtail > giant green foxtail = robust purple foxtail > robust white foxtail.


1990 ◽  
Vol 68 (12) ◽  
pp. 2564-2570 ◽  
Author(s):  
Suzanne Racette ◽  
Isabelle Louis ◽  
John G. Torrey

The term cluster root is used to refer to a dense cluster of determinate lateral roots (rootlets), in preference to the terms proteoid root and proteoid-like root used by other authors. Cluster roots are often formed by the actinorhizal plant Gymnostoma papuanum. In water culture, cluster root formation by G. papuanum was influenced by aeration, phosphorus level, and nitrogen source. Aeration was a critical factor, with nonaerated rooted cuttings having far fewer cluster roots than aerated ones. Phosphorus deficiency was the single nutrient deficiency that led to increased cluster root formation. Seedlings, grown under conditions of either low (0.8 mg∙L−1) or no phosphorus, responded by devoting a greater portion of root growth to the production of cluster roots, with no overall reduction in root growth for 6 weeks. The response to varying phosphorus level was modified by providing nitrogen in different forms. Supplying nitrogen as ammonium resulted in low levels of cluster root formation. Supplying nitrate to nodulated seedlings led to an increase in cluster root formation in comparison with plants that depended solely upon dinitrogen fixation by Frankia. Greatest cluster root formation occurred on plants grown in aerated water cultures supplied with nitrate and with little or no phosphorus. Key words: Gymnostoma papuanum, cluster roots, proteoid roots, phosphorus deficiency.


1991 ◽  
Vol 42 (1) ◽  
pp. 95
Author(s):  
BJ Atwell

Lupins (Lupinus angustifolius cvv. Yandee and 75A-258 and L. pilosus cv. P. 20957) and pea (Pisum sativum cv. Dundale) were grown in the field for 43 days on a solonized brown soil. Shoots of L. pilosus and peas grew most rapidly, while L. angustifolius cv. 75A-258 developed a relatively large root system. L. angustifolius cv. Yandee, a commercial lupin cultivar, was poorly adapted; shoot growth was restricted and roots ceased growing 36 days after sowing. The soil factors responsible for these widely differing responses were investigated. Once primary roots of L. angustifolius were 20-30 cm deep, root extension was slow or arrested. Indeed, primary root apices of Yandee were often necrotic in the soil below 20 cm. In contrast, roots proliferated rapidly in the surface 20 cm of the soil, particularly in 7SA-258, suggesting that factors in the deeper soil layers restricted root growth most severely. The vigorous growth of lateral roots of 75A-258 was reflected in a 2.6 fold greater total root length than for Yandee 43 days after sowing. Soil physical properties were not considered a likely explanation for these observations; soil water status and porosity were always favourable for root growth and root sections indicated that no cortical degradation, typical of O2 deficient roots, had occurred. Penetrometer resistance and root tip osmotic pressures suggested that poor root growth could not be ascribed simply to soil mechanical properties. The results suggest, by inference, that soil chemical factors could underlie the phenotypic responses observed.


2020 ◽  
Vol 48 (2) ◽  
pp. 906-923
Author(s):  
Yahya ALZAHRANI ◽  
Hesham F. ALHARBY ◽  
Khalid R. HAKEEM ◽  
Hameed ALSAMADANY

The present study investigated the influence of inorganic amendments viz., SDS (sodium dodecyl sulphate) and ethylenediaminetetraacetic acid (EDTA) in enhancing metal tolerance in plants. Seedlings of an important ornamental plant, Dahlia variabilis Cav. were grown under cadmium (Cd) and lead (Pb) stress. 30-days old seedlings were transferred to pots containing sterilized sand and supplemented with Hoagland’s medium. After 15 days of transplanting, four treatments (0, 10, 25, and 100 mg kg-1) of Cd and four treatments of Pb (0, 100, 500 and 5000 mg kg-1) were used with or without application of 2.0 mM SDS and 2.5 mM EDTA, separately and in combination. Seedlings were further grown for 60 days in culture media. Results revealed that both Cd and Pb significantly reduced plant growth, pigment content, and relative water content. Antioxidant enzymes viz., superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein and total soluble sugar contents showed a declining trend with an increase in Cd and Pb concentrations applied. The Cd and Pb treatment enhanced the production rate of reactive oxygen species (ROS) as depicted by the increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) production in leaf. Inorganic amendments viz., EDTA+SDS applied either alone or in combination significantly alleviated Cd and Pb-induced toxic effects. However, a combination of EDTA+SDS showed significant results than used separately. These results revealed that the application of inorganic amendments in combination can enhance the phytoextraction capacity of the species studied. However, the effects of various amendments vary with the nature of the inorganic compound. The study suggests that the application of EDTA and SDS could be a useful strategy for enhancing the phytoextraction capability of Dahlia variabilis to remove Cd and Pb from contaminated soils.


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