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 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.

scholarly journals Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2058
Author(s):  
Iván P. Ordóñez ◽  
Ignacio F. López ◽  
Peter D. Kemp ◽  
Daniel J. Donaghy ◽  
Yongmei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Root Growth ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Leaf Stage ◽  
Water Soluble Carbohydrates ◽  
Stage Development ◽  
Defoliation Frequency ◽  
Root Growth Rate

The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.

scholarly journals Root Morphology of Eight Hybrid Oil Palms Under Iron (Fe) Toxicity

2016 ◽  
Vol 1 (1) ◽  
pp. 013
Author(s):  
Aprilia Ike Nurmalasari ◽  
Eka Tarwaca Susila Putra ◽  
Prapto Yudono
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Surface Area ◽  
Root Morphology ◽  
Block Design ◽  
Dry Weight ◽  
Root Volume ◽  
Oil Palms ◽  
Fe Toxicity ◽  
Root Growth Rate

The research aims to study the change of morphology root characters of eight hybrid oil palms under iron toxicity (Fe). Field experiment done in arranged in a Randomized Complete Block Design (RCBD) two factors and three blocks as replications. The first factor was Fe concentration. It consists of two levels which are concentration 0µ.g-1 and concentration 600 µg.g-1 Fe. The second factor is the hybrid of oil palms which consists of eight hybrid oil palms as Yangambi, Avros, Langkat, PPKS 239, Simalungun, PPKS 718, PPKS 540 and Dumpy. Fe was applied by pouring FeSO4 solvent for 600 µg.g-1 500 ml.-1plant.-1day-1 on two months of plants after transplanting in the main nursery. Data were collected on root morphology and plant dry weight The data were analysis of variance (ANOVA) at 5% significanly, followed by Duncan's multiple range test (DMRT). The relationships by among variables were determined by correlation analysis. The results showed that Fe concentration 600 µg.g-1 inhibits relatively root growth rate, narrows surface area, reduces the diameter, and shrinks root volume of all hybrid oil palms tested. The slowing relatively root growth rate, narrowing of root surface area and root diameter also root volume shrinkage due to Fe stress. It was also shown that the dry weight of plants was inhibit by existing of Fe toxicity.

Statistical analysis of root growth rate determinations

1980 ◽  
Vol 20 (4) ◽  
pp. 389-396 ◽  
Author(s):  
Christopher Cox ◽  
Henry T. Davis ◽  
Morton W. Miller ◽  
Dominique Robertson
Keyword(s):  
Growth Rate ◽  
Statistical Analysis ◽  
Root Growth ◽  
Root Growth Rate

Dependence of Root Growth Rate on Holoploid DNA Content

2019 ◽  
Vol 50 (5) ◽  
pp. 257-260
Author(s):  
N. V. Zhukovskaya ◽  
E. I. Bystrova ◽  
N. F. Lunkova ◽  
V. B. Ivanov
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Dna Content ◽  
Root Growth Rate

Root Growth Rate of Soybean as Affected by Drought Stress 1

1987 ◽  
Vol 79 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Gerrit Hoogenboom ◽  
M. G. Huck ◽  
Curt M. Peterson
Keyword(s):  
Growth Rate ◽  
Drought Stress ◽  
Root Growth ◽  
Root Growth Rate

Maturation of the tracheary elements in the roots of Pinus banksiana and Eucalyptus grandis

2001 ◽  
Vol 79 (7) ◽  
pp. 844-849
Author(s):  
J H Taylor ◽  
C A Peterson
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Pinus Banksiana ◽  
Eucalyptus Grandis ◽  
Tracheary Element ◽  
Reliable Indicator ◽  
Root Tip ◽  
Tracheary Elements ◽  
Fluorescent Tracer ◽  
Root Growth Rate

Tracheary elements of the xylem are responsible for the longitudinal (axial) transport of water and ions that have moved radially across the root. These vessel members and (or) tracheids mature some distance behind the root tip, and it is generally believed that this distance is directly related to root growth rate. To test this idea, the distances behind the root tip at which tracheary elements of pouch-grown Pinus banksiana Lamb. and Eucalyptus grandis W. Hill ex Maiden mature were examined. From each species, three root tip types (white, brown, and ectomycorrhizal short lateral) were assessed. Unlike previous studies of this topic, two methods of testing tracheary element maturity were employed concurrently. The first was anatomical and involved visualizing the deposition of lignin in the walls of the tracheids or vessel members. The second was functional and consisted of determining the capability of the tracheary elements to conduct a fluorescent, tracer dye. The distance behind the root tip at which the conductive xylem cells mature varied from 0.16 to 1.6 mm and was highly dependent on species and root type. No significant correlation was found between growth rate and proximity of tracheary element maturation to the tip for white roots. The presence of lignin in the tracheary element wall was not a reliable indicator of the cell's functional maturity.Key words: conductivity, development, roots, tracheary elements, xylem.

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.

scholarly journals Clonal Variation in Lateral and Basal Rooting of Populus Irrigated with Landfill Leachate

2011 ◽  
Vol 60 (1-6) ◽  
pp. 35-44 ◽  
Author(s):  
R. S. Zalesny ◽  
J. A. Zalesny
Keyword(s):  
Growth Rate ◽  
Root Growth ◽  
Landfill Leachate ◽  
Clonal Selection ◽  
Lateral Roots ◽  
Adventitious Rooting ◽  
Clonal Variation ◽  
Basal Roots ◽  
Root Growth Rate ◽  
Root Types

AbstractSuccessful establishment and productivity ofPopulusdepends upon adventitious rooting from: 1)lateral rootsthat develop from either preformed or induced primordia and 2)basal rootsthat differentiate from callus at the base of the cutting in response to wounding. Information is needed for phytotechnologies about the degree to whichPopulusadventitious rooting is controlled by effects of individual genotypes, waste waters used as alternative fertigation sources, and their interactions. Our objective was to irrigate twelvePopulusclones with well water (control) or municipal solid waste landfill leachate and to test for differences between initiation of lateral versus basal roots, as well as root growth rate and distributional trends for both root types. We evaluated number and length of lateral roots initiated from upper, middle, and lower thirds of the cutting, as well as basal callus roots. Overall, leachate irrigation affected lateral roots but not basal roots, and there was broad clonal variation between and within root types. On average, there were 129% more lateral than basal roots, which ranged from 3 to 27 (lateral) and 2 to 10 roots (basal). The percent advantage of number of roots from the middle portion of the cutting relative to other sections was 120% (upper), 193% (lower), and 24% (basal). Clones, treatments, and their interaction did not affect root growth rate, which ranged from 1.5 ± 0.6 to 3.4 ± 0.3 cm d−1, with a mean of 2.3 ± 0.2 cm d−1. These results contribute baseline information for clonal selection needed to establishPopulusfor phytotechnologies, energy, and fiber.

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