Structural changes in phi thickenings during primary and secondary growth in roots. 1. Apple (Pyrus malus) Rosaceae

1983 ◽  
Vol 61 (10) ◽  
pp. 2570-2576 ◽  
Author(s):  
Carol Ann Weerdenburg ◽  
Carol A. Peterson
Keyword(s):  
Cross Sections ◽  
Structural Changes ◽  
Lateral Roots ◽  
Secondary Growth ◽  
Root Tip ◽  
Root Extract ◽  
Chelidonium Majus ◽  
Cortical Cells ◽  
Lateral Root Primordia ◽  
Mature Root

Whole roots and freehand cross sections of apple roots, cleared and stained with a root extract of Chelidonium majus L., revealed the presence of a uniseriate layer of phi thickenings. The layer, externally adjacent to the endodermis, consisted of cells with a heavy deposition of lignin in the thickened midportions of their transverse and radial walls. The thickenings were completely developed within 3–5 mm from the root tip. Lateral root primordia emerged through the phi layer by means of openings in the layer resulting from the removal of entire phi thickenings from the cortical cells. The layer was not continuous from the main to the lateral roots unlike the Casparian band of the endodermis. During secondary growth, the middle lamellae of the cells of the phi layer split, disrupting the regular appearance of the layer. Ultimately, the epidermis and cortex were sloughed off as the periderm, arising in the pericycle, developed to form the most external tissue of the mature root. However, remnants of the phi thickenings were persistent in many areas of the mature root.

Effect of secondary growth on the conformation and permeability of the endodermis of broad bean (Vicia faba), sunflower (Helianthus annuus), and garden balsam (Impatiens balsamina)

1984 ◽  
Vol 62 (5) ◽  
pp. 907-910 ◽  
Author(s):  
Carol Ann Weerdenburg ◽  
Carol A. Peterson
Keyword(s):  
Cross Sections ◽  
Broad Bean ◽  
Uv Light ◽  
Secondary Growth ◽  
Root Extract ◽  
Chelidonium Majus ◽  
Calcofluor White ◽  
Casparian Band ◽  
Apoplastic Barrier ◽  
Endodermal Cells

A root undergoing secondary growth exhibits massive girth increases owing to the activity of the vascular cambium. To determine the effects of this growth on endodermal structure and function, cleared cross sections from areas of primary and secondary growth in broad bean, sunflower, and garden balsam roots were examined. Casparian bands were detected by staining the sections with Chelidonium majus root extract and viewing them with ultraviolet (uv) light using an epifluorescence microscope. Endodermal diameter and numbers of endodermal cells increased dramatically in the area of secondary growth. The distance spanned by the Casparian band (i.e., the tangential width of the endodermal cells) between radial walls also increased except in sunflower. The permeability of the endodermis to an apoplastic fluorescent dye in roots undergoing secondary growth was tested by treatment with Calcofluor white M2R. In all species examined, the Casparian band continued to function as an effective apoplastic barrier during early stages of secondary growth despite the increase in endodermal cell size and number. Eventual decortication with concurrent disruption of the endodermis resulted in massive penetration of Calcofluor white M2R into the xylem.

Ontogeny of Alnus rubra – Alpova diplophloeus ectomycorrhizae. I. Light microscopy and scanning electron microscopy

1989 ◽  
Vol 67 (1) ◽  
pp. 191-200 ◽  
Author(s):  
H. B. Massicotte ◽  
R. L. Peterson ◽  
L. H. Melville
Keyword(s):  
Outer Layer ◽  
Lateral Root ◽  
Lateral Roots ◽  
Root Hairs ◽  
Fungal Colonization ◽  
Alnus Rubra ◽  
Cortical Cells ◽  
Lateral Root Primordia ◽  
Hartig Net ◽  
Fungal Hyphae

Ectomycorrhizae synthesized between Alpova diplophloeus and Alnus rubra are of two morphological types: one with a mantle formed along the entire length of the lateral roots and the other, the clavate type, with the mantle confined to the apical portion of the laterals. The morphology of the mycorrhiza is dependent on the stage of lateral root elongation at the time of colonization by fungal hyphae. Clavate mycorrhizae form on lateral roots that have already elongated at the time of fungal colonization. Fungal hyphae interact with root hairs at the base of clavate mycorrhizae. Mantles of both types are fairly compact with few extramatrical hyphae. Hartig net hyphae, which branch profusely primarily in the radial direction, are confined to the epidermis and midway along the radial walls of the outer layer of cortical cells. Second-order lateral root primordia are initiated in the mature Hartig net zone. Cells in the outer layer of the cortex of mycorrhizal roots collapse during fixation, indicating the possible presence of a barrier in the cell wall blocking the ingress of fixative.

scholarly journals Cell wall remodeling and vesicle trafficking mediate the root clock in Arabidopsis

2020 ◽  
Author(s):  
Guy Wachsman ◽  
Jingyuan Zhang ◽  
Miguel A. Moreno-Risueno ◽  
Charles T. Anderson ◽  
Philip N. Benfey
Keyword(s):  
Lateral Root ◽  
Structural Changes ◽  
Vesicle Trafficking ◽  
Lateral Roots ◽  
Primary Root ◽  
Root Primordia ◽  
Pavement Cell ◽  
Lateral Root Primordia ◽  
Periodic Gene ◽  
Significant Enrichment

AbstractIn Arabidopsis, lateral roots initiate along the primary root in a process preceded by periodic gene expression, a phenomenon known as the root clock. Many genes involved in lateral root initiation have been identified. However, very little is known about the structural changes underlying the initiation process nor about how root clock function is regulated. In genetic screens, we identified the vesicle trafficking regulators, GNOM and its suppressor, AGD3, as critical to root clock function. We show that GNOM is required for the proper distribution of pectin, a mediator of intercellular adhesion, and that pectin esterification state is essential for a functional root clock. We found that in sites of lateral root primordia emergence, both esterified and de-esterified pectin are differentially distributed. Using a reverse genetic approach, we identified significant enrichment of GO terms associated with pectin modifying enzymes in the oscillation zone were the root clock is established. In agreement with a recent study on the function of pectin in pavement cell morphogenesis, our results indicate that the balance between esterified and de-esterified pectin is essential for proper root clock function and the subsequent initiation of lateral root primordia.

scholarly journals Applicability of a Monolithic Column for Separation of Isoquinoline Alkalodis from Chelidonium majus Extract

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3612 ◽  
Author(s):  
Staniak ◽  
Wójciak-Kosior ◽  
Sowa ◽  
Strzemski ◽  
Sawicki ◽  
...  
Keyword(s):  
Monolithic Column ◽  
Gradient Elution ◽  
Root Extract ◽  
Organic Modifier ◽  
Isoquinoline Alkaloids ◽  
Chelidonium Majus ◽  
Peak Asymmetry ◽  
Application Potential ◽  
Chromatographic Plate ◽  
Chromatographic Parameters

Isoquinoline alkaloids are the main group of secondary metabolites present in Chelidonium majus extracts, and they are still the object of interest of many researchers. Therefore, the development of methods for the investigation and separation of the alkaloids is still an important task. In this work, the application potential of a silica-based monolithic column for the separation of alkaloids was assessed. The influence of the organic modifier, temperature, salt concentration, and pH of the eluent on basic chromatographic parameters such as retention, resolution between neighboring peaks, chromatographic plate numbers, and peak asymmetry were investigated. Based on the obtained results, a gradient elution program was developed and used to separate and quantitatively determine the main alkaloids in a Chelidonium majus root extract.

Myosin thick filament lability induced by mechanical strain in airway smooth muscle

2001 ◽  
Vol 90 (5) ◽  
pp. 1811-1816 ◽  
Author(s):  
Kuo-Hsing Kuo ◽  
Lu Wang ◽  
Peter D. Paré ◽  
Lincoln E. Ford ◽  
Chun Y. Seow
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Cross Sections ◽  
Structural Changes ◽  
Isometric Force ◽  
Mechanical Strain ◽  
Thick Filament ◽  
Functional Changes ◽  
Thick Filaments ◽  
Length Changes

Airway smooth muscle adapts to different lengths with functional changes that suggest plastic alterations in the filament lattice. To look for structural changes that might be associated with this plasticity, we studied the relationship between isometric force generation and myosin thick filament density in cell cross sections, measured by electron microscope, after length oscillations applied to the relaxed porcine trachealis muscle. Muscles were stimulated regularly for 12 s every 5 min. Between two stimulations, the muscles were submitted to repeated passive ±30% length changes. This caused tetanic force and thick-filament density to fall by 21 and 27%, respectively. However, in subsequent tetani, both force and filament density recovered to preoscillation levels. These findings indicate that thick filaments in airway smooth muscle are labile, depolymerization of the myosin filaments can be induced by mechanical strain, and repolymerization of the thick filaments underlies force recovery after the oscillation. This thick-filament lability would greatly facilitate plastic changes of lattice length and explain why airway smooth muscle is able to function over a large length range.

scholarly journals A PRELIMINARY STUDY OF THE MANGROVE FOREST ON PULAU RAMBUT, JAKARTA BAY

1970 ◽  
Vol 18 ◽  
pp. 119-129
Author(s):  
Kuswata Kartawinata ◽  
Eko B. Walujo
Keyword(s):  
Mangrove Forest ◽  
Structural Changes ◽  
Secondary Growth ◽  
Deep Soil ◽  
On This Island ◽  
Coral Island ◽  
Preliminary Study ◽  
Disturbed Forest ◽  
Flat Profile ◽  
Shallow Soils

Pulau Rambut (± 56ha) is one of the islands of the Pulau Seribu group. It is a coral island covered by disturbed forest and secondary growth at the center, and mangrove forest at its periphery. A study in a 290 x 10 m transect running south to north across the mangrove forest shows a distinct zonation as follows : the Scyphiphora hydrophyllacea - Lumnitzera racemosa community on coral flat with patchy shallow soils on the interior, the Rhizophora mucronata community on relatively deep soil overlaying coral formation, and the R. mucronata - R. stylosa community on periodically submerged coral flat. Profile diagrams established along the transect show structural changes also. The R. mucronata forest is the most developed community and appears to be the most prevalent. R. stylosa forms the pioneer species on this island.

scholarly journals Is the Responsiveness to Light Related to the Differences in Stem Straightness among Populations of Pinus pinaster?

Plants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 383
Author(s):  
Rosario Sierra-de-Grado ◽  
Valentín Pando ◽  
Pablo Martínez-Zurimendi ◽  
Bruno Moulia
Keyword(s):  
Cross Sections ◽  
Pinus Pinaster ◽  
Radial Growth ◽  
Wood Quality ◽  
Secondary Growth ◽  
Natural Populations ◽  
Ecological Features ◽  
Stem Straightness ◽  
One Year ◽  
Stem Curvature

Stem straightness is related to wood quality and yield. Although important genetic differences in stem straightness among the natural populations of Pinus pinaster are well established, the main drivers of these differences are not well known. Since the responses of trees to light are key ecological features that induce stem curvature, we hypothesized that populations with better straightness should exhibit lower photomorphogenetic and phototropic sensitivity. We compared three populations to identify the main processes driven by primary and secondary growth that explain their differences in response to light. One-year-old seedlings were grown under two treatments—direct sunlight and lateral light plus shade—for a period of 5 months. The length and the leaning of the stems were measured weekly. The asymmetry of radial growth and compression wood (CW) formation were analyzed in cross-sections. We found differences among the populations in photomorphogenetic and phototropic reactions. However, the population with straighter stems was not characterized by reduced sensitivity to light. Photo(gravi)tropic responses driven by primary growth and gravitropic responses driven by secondary growth explained the kinetics of the stem leaning and CW pattern. Asymmetric radial growth and CW formation did not contribute to the phototropic reactions.

Phytotoxic effects of phenolic compounds on Calopogonium mucunoides (Fabaceae) roots

2015 ◽  
Vol 63 (8) ◽  
pp. 679 ◽  
Author(s):  
Roberta Cristiane Ribeiro ◽  
Rodrigo Barbosa Braga Feitoza ◽  
Helena Regina Pinto Lima ◽  
Mário Geraldo de Carvalho
Keyword(s):  
Phenolic Compounds ◽  
Cinnamic Acid ◽  
Lateral Roots ◽  
Anatomical Variations ◽  
Root Diameter ◽  
Root Tip ◽  
Root Structure ◽  
Water Control ◽  
Calopogonium Mucunoides ◽  
Standard Techniques

Studies on phenols have gained attention owing to their abundance in plants and their effects on plant development. Phenols from forage grasses may exert phytotoxicity on legume crops in intercropping systems. We aimed to identify morpho-anatomical variations in Calopogonium mucunoides Desv. roots treated with phenolic compounds. Seeds of C. mucunoides were treated with (1) distilled water (control), (2) trans-cinnamic acid, (3) a mixture of the flavonoids quercetin, rutin, kaempferol and kaempferol-3-α-rhamnoside, or (4) a combination of the flavonoid mixture and trans-cinnamic acid. After 10 days of treatment, the roots were measured, described and processed according to standard techniques in plant anatomy. In general, non-control individuals showed plant lengths decreased by 40–45%, root-tip necrosis and intense lateral root ramification. Seeds germinated in cinnamic acid presented xylem poles with a greater number of cells and a greater emission of lateral roots. In the seeds treated with flavonoids, cell division was observed in the endodermis and the pericycle, and xylem fibres went through differentiation. The combination of cinnamic acid and flavonoids led to the premature formation of fibres by the phloem. The treatments with flavonoids or cinnamic acid alone were significantly greater in root diameter (868.61 µm and 810.35 µm, respectively) than was the application of both (714.98 µm) or the control (533.76 µm). The results suggest that cinnamic acid and the tested flavonoids negatively affect the development and the root structure of C. mucunoides.

Corrigendum - Factors which affects the growth of grain legumes on a solonized brown soil. I. Genotypic responses to soil physical factors

1991 ◽  
Vol 42 (1) ◽  
pp. 95
Author(s):  
BJ Atwell
Keyword(s):  
Root Growth ◽  
Water Status ◽  
Lateral Roots ◽  
Primary Root ◽  
Grain Legumes ◽  
Root Tip ◽  
Physical Factors ◽  
Brown Soil ◽  
Penetrometer Resistance ◽  
System L

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.

NaCl salinity affects lateral root development in Plantago maritima

2004 ◽  
Vol 31 (8) ◽  
pp. 775 ◽  
Author(s):  
Michael Rubinigg ◽  
Julia Wenisch ◽  
J. Theo M. Elzenga ◽  
Ineke Stulen
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Root Length ◽  
Lateral Root ◽  
Lateral Roots ◽  
Third Order ◽  
Lateral Root Primordia ◽  
Relative Growth ◽  
Length Growth ◽  
Lateral Root Length

Root growth and morphology were assessed weekly in hydroponically-grown seedlings of the halophyte Plantago maritima L. during exposure to 0, 50, 100 and 200 mm NaCl for 21 d. Relative growth rate was reduced by 25% at 200 mm NaCl. The lower NaCl treatments did not affect relative growth rates. Primary and lateral roots responded differently to NaCl. While primary-root length increased at all NaCl concentrations, total lateral-root length increased at 50 and was not affected at 100 mm but was considerably reduced at 200 mm NaCl. NaCl concentrations of 50 and 100 mm, which had no effect on relative growth rate or total lateral-root length, severely affected root branching pattern in that the number of first, second and third order laterals was reduced. At 200 mm NaCl third order laterals were not formed at all. However, mean lateral-root length was increased at all NaCl concentrations and was highest at 200 mm NaCl. We conclude that the increase in total lateral-root length in plants at 50 and 100 mm NaCl was mainly caused by increased length growth, while the decrease in total lateral-root length at 200 mm was the consequence of inhibition of lateral root primordia and / or the activation of apical meristems rather than reduced length growth.

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