THE ONTOGENY OF ADVENTITIOUS STEMS ON ROOTS OF CREEPING-ROOTED ALFALFA

1957 ◽  
Vol 35 (4) ◽  
pp. 463-475 ◽  
Author(s):  
Beatrice E. Murray
Keyword(s):  
Vascular System ◽  
Root Culture ◽  
Vascular Tissues ◽  
Phloem Parenchyma ◽  
Root Segments ◽  
Parenchyma Cells ◽  
Ontogenetic Study ◽  
Meristematic Activity

An ontogenetic study of adventitious stem formation on root segments of creeping-rooted alfalfa clones is presented. Unusual meristematic activity is evident first in the phellogen near a lateral rootlet. Continued activity in that region gives rise to a primordial dome from which adventitious stems eventually emerge. Concomitantly, in the subjacent phloem parenchyma cells dedifferentiation and subsequent redifferentiation into vascular tissues occurs. Thus a vascular system is formed which extends from the adventitious stems to the cambium region of the root and, in some instances, to the cambium of the lateral rootlet. Adventitious stems are initiated in secondary tissues of the root. Factors such as age of root, culture treatment, and inherent differences have an influence on adventitious stem initiation.

scholarly journals Morpho-Anatomical Analysis of the Rhizome in Species of Scleria Berg. (Cyperaceae) from Serra do Cipó (MG)

2009 ◽  
Vol 52 (6) ◽  
pp. 1473-1483 ◽  
Author(s):  
Vera Fatima Gomes Alves Pereira Lima ◽  
Nanuza Luiza de Menezes
Keyword(s):  
Adventitious Roots ◽  
Vascular System ◽  
Vascular Tissues ◽  
Serra Do Cipó ◽  
Anatomical Analysis ◽  
Meristematic Activity ◽  
Cell Layers ◽  
The Subject ◽  
Derivatives Of

Aspects related to the nature of stem thickening in monocotyledons have been the subject of many studies. Primary thickening has been attributed to the Primary Thickening Meristem (PTM). According to most authors, it gives rise, besides the adventitious roots, to the vascular tissues and part of the cortex. In other words, it has centripetal and centrifugal activity. For some authors, however, it gives rise only to the vascular system, and for others, only to part of the cortex. However, this work demonstrated that PTM corresponds to the pericycle in the meristematic phase or to the pericycle associated with the endodermis, also with meristematic activity. It was observed that the pericycle was responsible for the formation of the vascular system of the rhizome and of the adventitious roots; the endodermis gave rise to cell layers with radial disposition which comprised the inner portion of the stem cortex, and which corresponded to the region known as the derivatives of the meristematic endodermis (DME). A continuity was also demonstrated between the tissues of the stem and root in species of Scleria Berg. (Cyperaceae).

Vascularization of the scutellum of wheat

1970 ◽  
Vol 18 (1) ◽  
pp. 45 ◽  
Author(s):  
JG Swift ◽  
TP O'Brien
Keyword(s):  
Vascular System ◽  
Sieve Tube ◽  
Serial Sections ◽  
Phloem Tissue ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Single Ring

The pattern of vascularization of the wheat scutellum shortly after germination is reconstructed from serial sections of plastic-embedded specimens. Nearly half of the phloem in the scutellum is unaccompanied by xylem. Most of the phloem tissue consists of distinct strands, composed of a central sieve tube encircled by a single ring of phloem parenchyma cells. The possible functions of this unusual vascular system are discussed in detail.

scholarly journals Anatomy of Adventitious Root Formation in Microcuttings of Malus domestica Borkh. `Gala'

1993 ◽  
Vol 118 (5) ◽  
pp. 680-688 ◽  
Author(s):  
James F. Harbage ◽  
Dennis P. Stimart ◽  
Ray F. Evert
Keyword(s):  
Time Course ◽  
Root Formation ◽  
Adventitious Root Formation ◽  
Induction Treatment ◽  
Induction Medium ◽  
Root Induction ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Meristematic Activity ◽  
Cell Layers

Anatomical events of adventitious root formation in response to root induction medium, observing changes during induction and post-induction stages, were made with microcuttings of `Gala' apples. Shoot explants on root induction medium containing water, 1.5 μm IBA, 44 mm sucrose, or 1.5 μm IBA + 44 mm sucrose after 4 days of treatment averaged 0, 0.2, 2.2, and 11.9 meristemoids per microcutting, respectively. Meristemoids formed in response to sucrose were confined to leaf gaps and traces. Time-course analysis of root induction with 1.5 μm IBA + 44 mm sucrose over 4 days revealed that some phloem parenchyma cells became densely cytoplasmic, having nuclei with prominent nucleoli within 1 day; meristematic activity in the phloem was widespread by 2 days; continued division of phloem parenchyma cells advanced into the cortex by 3 days; and that identifiable root primordia were present by 4 days. Cell division of pith, vascular cambium, and cortex did not lead to primordia formation. Meristematic activity was confined to the basal 1 mm of microcuttings. Time-course analysis of post-induction treatment revealed differentiation of distinct cell layers at the distal end of primordia by 1 day; primordia with a conical shape and several cell layers at the distal end by 2 to 3 days; roots with organized tissue systems emerging from the stem by 4 days; and numerous emerged roots by 6 days. Root initiation was detectable within 24 hours and completed by day 4 of the root induction treatment and involved only phloem parenchyma cells. Chemical names used: 1 H -indole3-butryic acid (IBA).

Elemental Analysis of Phloem Tissue in Lemna Minor Root Tips

1980 ◽  
Vol 38 ◽  
pp. 798-799
Author(s):  
Patrick Echlin ◽  
Thomas Hayes ◽  
Clifford Lai ◽  
Greg Hook
Keyword(s):  
Vascular Tissue ◽  
Lemna Minor ◽  
Atomic Weight ◽  
Companion Cell ◽  
Root Tips ◽  
Phloem Tissue ◽  
Cell Stage ◽  
Phloem Parenchyma ◽  
Parenchyma Cells ◽  
Xylem Element

Studies (1—4) have shown that it is possible to distinguish different stages of phloem tissue differentiation in the developing roots of Lemna minor by examination in the transmission, scanning, and optical microscopes. A disorganized meristem, immediately behind the root-cap, gives rise to the vascular tissue, which consists of single central xylem element surrounded by a ring of phloem parenchyma cells. This ring of cells is first seen at the 4-5 cell stage, but increases to as many as 11 cells by repeated radial anticlinal divisions. At some point, usually at or shortly after the 8 cell stage, two phloem parenchyma cells located opposite each other on the ring of cells, undergo an unsynchronized, periclinal division to give rise to the sieve element and companion cell. Because of the limited number of cells involved, this developmental sequence offers a relatively simple system in which some of the factors underlying cell division and differentiation may be investigated, including the distribution of diffusible low atomic weight elements within individual cells of the phloem tissue.

Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. 1. Production and translocation of a necrosis-inducing toxin

1969 ◽  
Vol 47 (7) ◽  
pp. 1147-1151 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston
Keyword(s):  
Activated Carbon ◽  
Root System ◽  
Vascular System ◽  
Early Symptom ◽  
Vascular Tissues ◽  
Detached Leaves ◽  
Necrotic Spots ◽  
Whole Plants ◽  
Necrotic Spotting

Necrotic spotting of leaves is an early symptom of attack by Sclerotium bataticola on sunflowers. Spots appear after invasion of vascular tissues by the pathogen, which does not spread appreciably from the point of inoculation.Inoculation of one stem of plants split apically to give twin stems on one root system resulted in necrotic spotting of leaves first on the inoculated, and later on the uninoculated stem. Introducing cell-free filtrates of cultures of S. bataticola into sunflower plants or detached leaves resulted in production of the same type of necrotic spots. Introduction of eosin dye, which is translocated in the vascular system, into whole plants and detached leaves produced patterns of coloration similar to the patterns of necrotic spotting. The necrosis may be attributed to a translocatable toxin produced by the fungus.It is indicated that the toxin is neither an enzyme nor a protein. It has not been eluted after adsorption by activated carbon.

Association of malva vein-clearing virus and rhabdoviruslike particles with mottle and vein clearing of malva plants

1986 ◽  
Vol 64 (1) ◽  
pp. 85-89 ◽  
Author(s):  
Maria-Ivone C. Henriques ◽  
Fernando S. Henriques
Keyword(s):  
Inclusion Bodies ◽  
Inner Core ◽  
Dense Body ◽  
Mesophyll Cells ◽  
Cytoplasmic Inclusions ◽  
Thin Sections ◽  
Phloem Parenchyma ◽  
Vein Clearing ◽  
Perinuclear Space ◽  
Parenchyma Cells

Thin sections of malva (Malva sp.) leaves collected in the field and showing mottle and vein-clearing symptoms were examined by electron microscopy. Cytoplasmic inclusions typical of potyvirus and consisting of pinwheels, laminated aggregates, and scrolls were readily observed. In addition, rhabdoviruslike particles were also seen in the perinuclear space of phloem parenchyma cells and within membranous sacs scattered throughout the cytoplasm of other vascular bundle cells. Occasionally rhabdoparticles could be found embedded in an amorphous electron-dense body located within the cell vacuole. The rhabdovirus particles, approximately 75 × 300 nm, were bound by a membrane with outer projections and had an inner core displaying cross striations. The cytoplasm of infected mesophyll cells had chloroplasts containing large amorphous inclusion bodies and had extensive membranous tubules that were frequently associated with the potyvirus inclusions. These ultrastructural aspects, the size of the particles, and the data on host range indicate that malva plants under study were doubly infected by viruses which were tentatively identified as malva vein-clearing virus and a previously undescribed rhabdovirus.

Early modifications of the internodal anatomy of Glycine max sprayed with 2,4-DB

1979 ◽  
Vol 57 (12) ◽  
pp. 1340-1344 ◽  
Author(s):  
Thompson Demetrio Pizzolato ◽  
David L. Regehr
Keyword(s):  
Cell Division ◽  
Cell Enlargement ◽  
Secondary Phloem ◽  
Anatomical Changes ◽  
Phloem Parenchyma ◽  
Cortical Parenchyma ◽  
Parenchyma Cells ◽  
Radial Cell ◽  
Orderly Fashion ◽  
Stimulation Of

An aqueous spray of 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) induces anatomical changes in young Glycine internodes. Four days after spraying, the first symptoms appear outside the cambium when the interfascicular parenchyma cells and the adjacent cortical parenchyma cells enlarge and divide in several planes. Four days later, the metaphloem parenchyma cells in many of the leaf traces undergo considerable periclinal cell division and extensive radial cell enlargement. The phloem parenchyma cells of the late metaphloem and first secondary phloem enlarge and divide in a less orderly fashion. Fifteen days after treatment, the cortical parenchyma is modified into a band of radially seriate cells above the protophloem fibers. Products of this cambium-like region convert the cortex into a callus-like tissue. The size of starch grains is reduced initially in the phloem and xylem and later in the cortex. It appears that the stimuli produced by 2,4-DB move into the internode via the metaphloem of leaf traces. Despite the rapid obliteration of conducting phloem by the 2,4-DB induced stimulation of phloem parenchyma, an accelerated differentiation of secondary phloem compensates for this loss.

DISTRIBUTION OF VEGETATIVE STORAGE PROTEINS IN ROSACEAE

IAWA Journal ◽  
2003 ◽  
Vol 24 (4) ◽  
pp. 421-428
Author(s):  
Wei-Min Tian ◽  
Zheng-Hai Hu
Keyword(s):  
Seasonal Changes ◽  
Storage Proteins ◽  
Protein Body ◽  
Diagnostic Feature ◽  
Secondary Phloem ◽  
Apple Trees ◽  
Phloem Parenchyma ◽  
Vegetative Storage Proteins ◽  
Parenchyma Cells ◽  
First Time

The distribution pattern of vegetative storage proteins is reported for the first time for 18 species and 2 varieties of twelve genera of Rosaceae. Vegetative storage proteins were present in all the species studied of Prunoideae and absent in Maloideae. Their occurrence in a genus seemed to be either universal or entirely absent. Rosaceae trees were poor in vegetative storage proteins and the form of vegetative storage proteins was not protein body-like. Granular and floccular forms of vegetative storage proteins could be distinguished exclusively in the secondary phloem parenchyma cells and their distribution was cell-specific. Our results suggest that the distribution of vegetative storage proteins in Rosaceae can be considered as a taxonomically diagnostic feature. The nature of the bark proteins with seasonal changes in apple trees is discussed.

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