The nodal roots of Zea: their development in relation to structural features of the stem

1986 ◽  
Vol 64 (11) ◽  
pp. 2524-2537 ◽  
Author(s):  
D. C. Hoppe ◽  
M. E. McCully ◽  
C. L. Wenzel
Keyword(s):  
Root System ◽  
Primary Root ◽  
Ground Level ◽  
Structural Features ◽  
Nodal Roots ◽  
Extensive Region ◽  
Nodal Root ◽  
The Mean ◽  
Xylem Conduits

The framework of the root system of a mature, field-grown corn plant of variety Seneca Chief consists of about 70 axile roots. One of these is the primary root. The others develop on the stem, a single tier at each of the seven basal nodes. Just over half of these roots grow out at or above ground level from nodes 6 and 7 late in the development of the plant, with those of node 7 entering the soil just before flowering. The mean diameter of the root produced at successively higher nodes increases, as does also the mean number of large metaxylem elements seen in a cross section, so that about 75% of the large xylem conduits between the root system and the stem are in the roots of the two uppermost tiers. Nodal root primordia develop initially in situ from an extensive region of dedifferentiated stem cortex. A sleeve-like extension of the stem encloses the base of each root formed at aerial nodes. At each node the complexity of vascular interconnections results in all of the framework roots being indirectly linked to each other and to the vascular traces from all of the leaves.

scholarly journals Cost-Benefit Analysis of the Upland-Rice Root Architecture in Relation to Phosphate: 3D Simulations Highlight the Importance of S-Type Lateral Roots for Reducing the Pay-Off Time

2021 ◽  
Vol 12 ◽  
Author(s):  
Daniel Gonzalez ◽  
Johannes Postma ◽  
Matthias Wissuwa
Keyword(s):  
Root System ◽  
Lateral Roots ◽  
Root Hairs ◽  
P Uptake ◽  
Root Tissue ◽  
Rice Root ◽  
P Deficiency ◽  
Nodal Roots ◽  
Nodal Root ◽  
Off Time

The rice root system develops a large number of nodal roots from which two types of lateral roots branch out, large L-types and fine S-types, the latter being unique to the species. All roots including S-types are covered by root hairs. To what extent these fine structures contribute to phosphate (P) uptake under P deficiency was investigated using a novel 3-D root growth model that treats root hairs as individual structures with their own Michaelis-Menten uptake kinetics. Model simulations indicated that nodal roots contribute most to P uptake followed by L-type lateral roots and S-type laterals and root hairs. This is due to the much larger root surface area of thicker nodal roots. This thickness, however, also meant that the investment in terms of P needed for producing nodal roots was very large. Simulations relating P costs and time needed to recover that cost through P uptake suggest that producing nodal roots represents a considerable burden to a P-starved plant, with more than 20 times longer pay-off time compared to S-type laterals and root hairs. We estimated that the P cost of these fine root structures is low enough to be recovered within a day of their formation. These results expose a dilemma in terms of optimizing root system architecture to overcome P deficiency: P uptake could be maximized by developing more nodal root tissue, but when P is growth-limiting, adding more nodal root tissue represents an inefficient use of the limiting factor P. In order to improve adaption to P deficiency in rice breeding two complementary strategies seem to exist: (1) decreasing the cost or pay-off time of nodal roots and (2) increase the biomass allocation to S-type roots and root hairs. To what extent genotypic variation exists within the rice gene pool for either strategy should be investigated.

Effect of nitrogen and phosphorus deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici

1989 ◽  
Vol 40 (3) ◽  
pp. 489 ◽  
Author(s):  
RF Brennan
Keyword(s):  
Root System ◽  
Phosphorus Deficiency ◽  
Gaeumannomyces Graminis ◽  
Nitrogen And Phosphorus ◽  
Nodal Roots ◽  
Proximal Lesion ◽  
Nodal Root ◽  
Seminal Roots ◽  
Four Levels ◽  
Take All

Wheat was grown in a slightly acid grey sand at six levels of phosphorus and four levels of nitrogen, in the presence and absence of inoculum of Gaeurnannomyces graminis tritici (Ggt) in a glasshouse experiment. Adequate nutrition of N (400 mg/pot) and P (100 mg/pot) for wheat plants was required to overcome take-all of wheat grown for 46 days. Severely N and P deficient plants had 60% of their seminal and nodal roots infected by take-all. As the plants responded to increasing levels of N and P, the percentage of infected nodal and seminal roots steadily declined to 0% and 10% for each root system respectively at luxury levels of P and adequate N. In both the seminal and nodal root system, increasing the N and P supply decreased the length of proximal lesions (closest to seed) and increased the length of the root between the crown and the proximal lesion. The seminal root system was more severely infected with take-all than the nodal root system.

scholarly journals Concentrations of Ground-Level Ozone on Petroleum Filling Stations in Urban West Region- Zanzibar

2021 ◽  
pp. 37-44
Author(s):  
Saadat Soud Mohamed ◽  
Abdul Ali Juma Mohamed ◽  
Chukwuma J. Okafor
Keyword(s):  
Ground Level ◽  
Spatial Variations ◽  
Mean Values ◽  
Ground Level Ozone ◽  
Environment And Health ◽  
West Region ◽  
Ambient Concentration ◽  
Gas Detector ◽  
The Mean

Ambient concentration of ground-level ozone was quantified from 14 petroleum filling stations in Urban and West districts allocated in urban west region Zanzibar between August and November 2019. In situ measurement was conducted for two separate sessions that involved before noon and afternoon in each day in the field using BH-4S Portable multi-gas detector. The analyzed data revealed both temporary and spatial variations of measured parameters. During phase1, the range of ozone was 4.8- 0.6 ppm. During phase2, the range of ozone was 14.2 - 4.5 ppm. The mean values recorded for ozone ranged from 0.6 ppm to 4.8 ppm for phase1, and from 4.5 ppm to 14.2 ppm for phase2. This study revealed that, ground-level ozone is at a point that calls attention tothe environment and health sectors.

Distribution and variation of hydroxamic acids and related compounds in maize (Zea mays) root system

1991 ◽  
Vol 69 (3) ◽  
pp. 677-681 ◽  
Author(s):  
Y. S. Xie ◽  
J. T. Arnason ◽  
B. J. R. Philogène ◽  
J. Atkinson ◽  
P. Morand
Keyword(s):  
Root System ◽  
High Performance ◽  
Primary Root ◽  
Hydroxamic Acids ◽  
Maize Root ◽  
Root Extracts ◽  
Nodal Roots ◽  
Maize Varieties ◽  
Maize Roots ◽  
Related Compounds

The concentrations of hydroxamic acids and related compounds, 2, 4-dihydroxy-7,8-dimethoxy-1,4-benzoxazin-3(4H)-one (DIM2BOA), 2-hydroxy-7,8-dimethoxy-1,4-benzoxazin-3(4H)-one (HMBOA), 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3(4H)-one (DIMBOA), and 6-methoxybenzoxazolinone (MBOA), in roots of 1- to 5-week-old maize plants were determined by high-performance liquid chromatography (HPLC). The highest concentrations of DIM2BOA, HMBOA, and total related compounds were found in maize root extracts when maize roots were 2 weeks old and the maize plant was approximately 15 cm in height. The highest concentrations of DIMBOA equivalents were found in 4-week-old maize root extracts. The distribution of individual compounds in different tissues (cortex, stele, and complete organ) of various root parts (first set of nodal roots, secondary roots, primary root, mesocotyl, and adventitious roots from mesocotyl) was also determined. Hydroxamic acids and related compounds are concentrated in the cortex of all parts of maize roots determined except mesocotyl. The concentrations of total related compounds and all individual compounds except HMBOA in complete organ of nodal roots were significantly higher than any other parts of maize roots. The high concentrations of these substances in the cortex of maize root may be relevant in the resistance of maize varieties to subterranean pest insects. Key words: hydroxamic acids, 1,4-benzoxazin-3-ones, maize, root system.

Novel Formulation Development and Evaluation of Nanoparticles Based in Situ Gelling System for The Ophthalmic Delivery of Ciprofloxacin Hydrochloride

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
Kranti Singh ◽  
Surajpal Verma ◽  
Shyam Prasad ◽  
Indu Bala
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Drug Loading ◽  
In Vitro Release ◽  
Formulation Development ◽  
Ciprofloxacin Hydrochloride ◽  
Potential Value ◽  
The Mean ◽  
In Situ Gelling

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

scholarly journals Comprehensive Genome-Wide Association Analysis Reveals the Genetic Basis of Root System Architecture in Soybean

2020 ◽  
Vol 11 ◽  
Author(s):  
Waldiodio Seck ◽  
Davoud Torkamaneh ◽  
François Belzile
Keyword(s):  
Root System ◽  
System Architecture ◽  
Phenotypic Variation ◽  
Genetic Basis ◽  
Genome Wide Association Study ◽  
Primary Root ◽  
Root System Architecture ◽  
Genome Wide Association ◽  
Nucleotide Polymorphisms ◽  
Genome Wide

Increasing the understanding genetic basis of the variability in root system architecture (RSA) is essential to improve resource-use efficiency in agriculture systems and to develop climate-resilient crop cultivars. Roots being underground, their direct observation and detailed characterization are challenging. Here, were characterized twelve RSA-related traits in a panel of 137 early maturing soybean lines (Canadian soybean core collection) using rhizoboxes and two-dimensional imaging. Significant phenotypic variation (P < 0.001) was observed among these lines for different RSA-related traits. This panel was genotyped with 2.18 million genome-wide single-nucleotide polymorphisms (SNPs) using a combination of genotyping-by-sequencing and whole-genome sequencing. A total of 10 quantitative trait locus (QTL) regions were detected for root total length and primary root diameter through a comprehensive genome-wide association study. These QTL regions explained from 15 to 25% of the phenotypic variation and contained two putative candidate genes with homology to genes previously reported to play a role in RSA in other species. These genes can serve to accelerate future efforts aimed to dissect genetic architecture of RSA and breed more resilient varieties.

scholarly journals The Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 Gene Is Involved in Anisotropic Root Growth during Osmotic Stress Adaptation

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 236
Author(s):  
María Belén Cuadrado-Pedetti ◽  
Inés Rauschert ◽  
María Martha Sainz ◽  
Vítor Amorim-Silva ◽  
Miguel Angel Botella ◽  
...  
Keyword(s):  
Osmotic Stress ◽  
Root Growth ◽  
Cell Walls ◽  
Primary Root ◽  
Stress Adaptation ◽  
Elongation Zone ◽  
Cortical Cells ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean

Mutations in the Arabidopsis TETRATRICOPEPTIDE THIOREDOXIN-LIKE 1 (TTL1) gene cause reduced tolerance to osmotic stress evidenced by an arrest in root growth and root swelling, which makes it an interesting model to explore how root growth is controlled under stress conditions. We found that osmotic stress reduced the growth rate of the primary root by inhibiting the cell elongation in the elongation zone followed by a reduction in the number of cortical cells in the proximal meristem. We then studied the stiffness of epidermal cell walls in the root elongation zone of ttl1 mutants under osmotic stress using atomic force microscopy. In plants grown in control conditions, the mean apparent elastic modulus was 448% higher for live Col-0 cell walls than for ttl1 (88.1 ± 2.8 vs. 16.08 ± 6.9 kPa). Seven days of osmotic stress caused an increase in the stiffness in the cell wall of the cells from the elongation zone of 87% and 84% for Col-0 and ttl1, respectively. These findings suggest that TTL1 may play a role controlling cell expansion orientation during root growth, necessary for osmotic stress adaptation.

scholarly journals Investigation of dominant traveling 10-day wave components using long-term MERRA-2 database

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Chunming Huang ◽  
Wei Li ◽  
Shaodong Zhang ◽  
Gang Chen ◽  
Kaiming Huang ◽  
...  
Keyword(s):  
Flow Instability ◽  
Transmission Condition ◽  
Wave Number ◽  
Mean Flow ◽  
Excited Wave ◽  
Propagating Waves ◽  
Zonal Wave Number ◽  
The Mean

AbstractThe eastward- and westward-traveling 10-day waves with zonal wavenumbers up to 6 from surface to the middle mesosphere during the recent 12 years from 2007 to 2018 are deduced from MERRA-2 data. On the basis of climatology study, the westward-propagating wave with zonal wave number 1 (W1) and eastward-propagating waves with zonal wave numbers 1 (E1) and 2 (E2) are identified as the dominant traveling ones. They are all active at mid- and high-latitudes above the troposphere and display notable month-to-month variations. The W1 and E2 waves are strong in the NH from December to March and in the SH from June to October, respectively, while the E1 wave is active in the SH from August to October and also in the NH from December to February. Further case study on E1 and E2 waves shows that their latitude–altitude structures are dependent on the transmission condition of the background atmosphere. The presence of these two waves in the stratosphere and mesosphere might have originated from the downward-propagating wave excited in the mesosphere by the mean flow instability, the upward-propagating wave from the troposphere, and/or in situ excited wave in the stratosphere. The two eastward waves can exert strong zonal forcing on the mean flow in the stratosphere and mesosphere in specific periods. Compared with E2 wave, the dramatic forcing from the E1 waves is located in the poleward regions.

Estimating Global Ocean Heat Content Changes in the Upper 1800 m since 1950 and the Influence of Climatology Choice*

2014 ◽  
Vol 27 (5) ◽  
pp. 1945-1957 ◽  
Author(s):  
John M. Lyman ◽  
Gregory C. Johnson
Keyword(s):  
Heat Content ◽  
Ocean Heat Content ◽  
Global Ocean ◽  
Ocean Temperature ◽  
Vertical Separation ◽  
Ocean Heat Uptake ◽  
Expendable Bathythermograph ◽  
Heat Uptake ◽  
The Mean

Abstract Ocean heat content anomalies are analyzed from 1950 to 2011 in five distinct depth layers (0–100, 100–300, 300–700, 700–900, and 900–1800 m). These layers correspond to historic increases in common maximum sampling depths of ocean temperature measurements with time, as different instruments—mechanical bathythermograph (MBT), shallow expendable bathythermograph (XBT), deep XBT, early sometimes shallower Argo profiling floats, and recent Argo floats capable of worldwide sampling to 2000 m—have come into widespread use. This vertical separation of maps allows computation of annual ocean heat content anomalies and their sampling uncertainties back to 1950 while taking account of in situ sampling advances and changing sampling patterns. The 0–100-m layer is measured over 50% of the globe annually starting in 1956, the 100–300-m layer starting in 1967, the 300–700-m layer starting in 1983, and the deepest two layers considered here starting in 2003 and 2004, during the implementation of Argo. Furthermore, global ocean heat uptake estimates since 1950 depend strongly on assumptions made concerning changes in undersampled or unsampled ocean regions. If unsampled areas are assumed to have zero anomalies and are included in the global integrals, the choice of climatological reference from which anomalies are estimated can strongly influence the global integral values and their trend: the sparser the sampling and the bigger the mean difference between climatological and actual values, the larger the influence.

scholarly journals Electron microscopy of synthetic myosin filaments. Evidence for cross-bridge. Flexibility and copolymer formation.

1975 ◽  
Vol 67 (1) ◽  
pp. 93-104 ◽  
Author(s):  
T D Pollard
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Structural Features ◽  
Length Frequency ◽  
Single Population ◽  
Skeletal Muscle Myosin ◽  
Distinctive Features ◽  
Myosin Filaments ◽  
The Mean ◽  
Muscle Myosin

Electron micrographs of negatively stained synthetic myosin filaments reveal that surface projections, believed to be the heads of the constituent myosin molecules, can exist in two configurations. Some filaments have the projections disposed close to the filament backbone. Other filaments have all of their projections widely spread, tethered to the backbone by slender threads. Filaments formed from the myosins of skeletal muscle, smooth muscle, and platelets each have distinctive features, particularly their lengths. Soluble mixtures of skeletal muscle myosin with either smooth muscle myosin or platelet myosin were dialyzed against 0.1 M KC1 at pH 7 to determine whether the simultaneous presence of two types of myosin would influence the properties of the filaments formed. In every case, a single population of filaments formed from the mixtures. The resulting filaments are thought to be copolymers of the two types of myosin, for several reasons: (a) their length-frequency distribution is unimodal and differs from that predicted for a simple mixture of two types of myosin filaments; (b) their mean length is intermediate between the mean lengths of the filaments formed separately from the two myosins in the mixture; (c) each of the filaments has structural features characteristic of both of the myosins in the mixture; and (d) their size and shape are determined by the proportion of the two myosins in the mixture.

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