Initiation of adventitious root primordia in very young Pinusbanksiana seedling cuttings

1983 ◽  
Vol 13 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Cheryl R. Montain ◽  
Bruce E. Haissig ◽  
John D. Curtis
Keyword(s):  
Transition Zone ◽  
Adventitious Root ◽  
Secondary Xylem ◽  
Vascular Cambium ◽  
Root Initiation ◽  
Secondary Phloem ◽  
Root Primordia ◽  
Cortical Cells ◽  
Parenchyma Cells ◽  
Resin Canals

The present work describes the anatomy of adventitious root initiation in 20-day-old Pinusbanksiana Lamb, seedling cuttings propagated under intermittent mist. Shortly after cuttings were made, basal necrosis occurred in all tissues (epidermis, periderm, cortex, primary and secondary phloem, and vascular cambium) that surrounded the central xylem cylinder. Thereafter, a relatively small "callus complex" composed of parenchyma cells, a few secondary xylem tracheids, and incompletely differentiated callus vascular cambium and periderm developed at the base of cuttings. One or sometimes two root primordia initiated in the transition zone between the lowermost cortical cells of the hypocotyl and the uppermost callus parenchyma cells. Primordia invariably arose just outside one of the four axial resin canals in the hypocotyl. Results suggested that adventitious root primordia may be initiated in P. banksiana cuttings only in association with differentiated or differentiating resin canals.

Differentiation of adventitious root primordia in callus of Pinusbanksiana seedling cuttings

1983 ◽  
Vol 13 (1) ◽  
pp. 195-200 ◽  
Author(s):  
Cheryl R. Montain ◽  
Bruce E. Haissig ◽  
John D. Curtis
Keyword(s):  
Adventitious Root ◽  
Secondary Xylem ◽  
Root Systems ◽  
Vascular Cambium ◽  
Root Primordia ◽  
Specific Identification ◽  
Resin Canals

The root systems of 97-day-old seedlings of Pinusbanksiana Lamb, were severed just below the lowermost needles, and the cuttings were placed in misted propagation benches. A complex of tissues including callus, vascular cambium, secondary xylem, periderm, and resin canals formed at the base of cuttings. Adventitious root primordia were initiated at the periphery of the basal-most portions of this complex in association with resin canals, tracheid "nests", periderm, and, possibly callus vascular cambium. Anatomical complexity of the developing tissues precluded more specific identification of sites of primordium initiation.

Carboniferous pteridosperm studies: morphology and anatomy of Schopfiastrum decussatum

1972 ◽  
Vol 50 (12) ◽  
pp. 2649-2658 ◽  
Author(s):  
Gar W. Rothwell ◽  
Thomas N. Taylor
Keyword(s):  
Secondary Xylem ◽  
Vascular Cambium ◽  
Secondary Phloem ◽  
Outer Cortex ◽  
Southern Illinois ◽  
Leaf Arrangement ◽  
Resin Canals ◽  
Inner Cortex

The monostelic seed fern Schopfiastrum decussatum Andrews is described from a specimen collected at a Middle Pennsylvanian petrifaction locality in southern Illinois. The specimen measures 24 cm long and is about 1.1 cm in diameter. Two petioles are attached to the axis and abundant foliar material is also present. Leaf arrangement is alternate and distichous. The stem consists of an exarch protostele surrounded by a prominent zone of secondary xylem. Secondary phloem and a vascular cambium are also preserved. The cortex is characterized by an undulating outer epidermal zone consisting of alternating ridges and furrows; internally this zone is delimited by conspicuous lacunae. Sclerenchyma bands occur in the outer cortex, with prominent resin canals present in the inner cortex. The fronds are represented by dichotomizing rachides, primary pinnae, and laminar pinnules. Features of the plant are compared to those of other Carboniferous pteridosperms, and a reconstruction of Schopfiastrum is included.

REACTION TISSUES IN GNETUM GNEMON A PRELIMINARY REPORT

IAWA Journal ◽  
2001 ◽  
Vol 22 (4) ◽  
pp. 401-413 ◽  
Author(s):  
P. B. Tomlinson
Keyword(s):  
Cell Walls ◽  
Tension Wood ◽  
Secondary Xylem ◽  
Secondary Phloem ◽  
Outer Cortex ◽  
Cortical Cells ◽  
Wood Fibres ◽  
Developmental Feature ◽  
Gnetum Gnemon ◽  
Clear Differentiation

Gnetum gnemon exhibits Rouxʼs model of tree architecture, with clear differentiation of orthotropic from plagiotropic axes. All axes have similar anatomy and react to displacement in the same way. Secondary xylem of displaced stems shows little eccentricity of development and no reaction anatomy. In contrast, there is considerable eccentricity in extra-xylary tissue involving both primary and secondary production of apparent tension-wood fibres (gelatinous fibres) of three main kinds. Narrow primary fibres occur concentrically in all axes in the outer cortex as a normal developmental feature. In displaced axes gelatinous fibres are developed abundantly and eccentrically on the topographically upper side, from pre-existing and previously undetermined primary cortical cells. They are wide with lamellate cell walls. In addition narrow secondary phloem fibres are also differentiated abundantly and eccentrically on the upper side of displaced axes. These gelatinous fibres are narrow and without obviously lamellate cell walls. Eccentric gelatinous fibres thus occupy a position that suggests they have the function of tension wood fibres as found in angiosperms. This may be the first report in a gymnosperm of fibres with tension capability. Gnetum gne-mon thus exhibits reaction tissues of unique types, which are neither gymnospermous nor angiospermous. Reaction tissues seem important in maintaining the distinctive architecture of the tree.

Development of Included Phloem in the Stem of Combretum Nigricans (Combretaceae)

IAWA Journal ◽  
1995 ◽  
Vol 16 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. W. den Outer ◽  
W. L. H. van Veenendaal
Keyword(s):  
Secondary Xylem ◽  
Vascular Cambium ◽  
Secondary Phloem ◽  
Xylem Parenchyma ◽  
Long Period ◽  
Short Period ◽  
Outer Border

The development of diffuse included phloem strands in Combretum nigricans sterns is described, During a short period of time, a small phloem strand is cut off locally in an inward direction by an otherwise normal bidirectional vascular cambium. This contrasts with previous descriptions and interpretations because these strands are not formed after redifferentiation of secondary xylem parenchyma. A complementary cambium formed at the inner border of the young strand somewhat enlarges the strand and, during a relatively long period, produces secondary phloem outwards. Finally this complementary cambium stops functioning as a cambium and merges with the secondary phloem it has produced. Radial rows of cells are present within the included phloem strands which continue into the later-formed secondary xylem; rays transverse the strands. Crushing of the phloem takes place near the outer border of the strand, forming cap-like tissues of disorganized cells.

Callus Formation and Root Initiation in Stem Cuttings of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco)

1972 ◽  
Vol 2 (2) ◽  
pp. 121-134 ◽  
Author(s):  
J. C. Heaman ◽  
J. N. Owens
Keyword(s):  
Callus Formation ◽  
Douglas Fir ◽  
Vascular Cambium ◽  
Complex Pattern ◽  
Root Initiation ◽  
Stem Cuttings ◽  
Root Primordia ◽  
Weekly Basis ◽  
Vascular Tissues ◽  
Rooting Response

Changes taking place at the base of stem cuttings of Douglas-fir during callus formation and root initiation are described. Material was taken from nine sources, including trees of different ages and with different histories of rooting response. Gross morphology and anatomy of the cutting bases are described using serial longitudinal sections of samples taken on a weekly basis over a 4-month period. The basal callus proliferated from the lowest cells of the vascular cambium and a complex pattern of differentiating vascular tissues arose within the callus mass. The root primordia arose in this callus in association with the differentiating phloem and wound cambium. Variation in callus formation and root initiation is described both within and between clones.

Variability in the Distribution of Middle Lamella Lignin in Secondary Vascular Tissues of Kenaf Stems

IAWA Journal ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 61-68
Author(s):  
Seung Gon Wi ◽  
Kwang Ho Lee ◽  
Hyeun Jong Bae ◽  
Byung Dae Park ◽  
Adya P. Singh
Keyword(s):  
Cell Walls ◽  
Secondary Xylem ◽  
Middle Lamella ◽  
Hibiscus Cannabinus ◽  
Secondary Phloem ◽  
Xylem Parenchyma ◽  
Vascular Tissues ◽  
Transmission Electron ◽  
Parenchyma Cells ◽  
Xylem Elements

Lignin in the middle lamella of the secondary xylem of angiosperms appears to be inhomogeneously distributed, based on studies where the focus is on a close examinantion of the middle lamella region of fibre cell walls by transmission electron microscopy (TEM). This is in contrast to the secondary xylem of gymnosperms which often display a more uniform distribution of lignin in the middle lamella of secondary xylem elements. The aim of our study was to undertake TEM examination of kenaf (Hibiscus cannabinus L.), an angiosperm plant mainly cultivated for its high quality secondary phloem fibres, to investigate lignin distribution in the middle lamella of secondary vascular tissues, including secondary phloem fibres. The middle lamella displayed considerable heterogeneity in the distribution of lignin in all lignified secondary vascular tissues, including xylem and phloem fibres, vessels and axial xylem parenchyma cells. The results provided evidence of lignin inhomogeneity in the secondary phloem fibres as well as in other lignified elements of kenaf vascular tissues, extending previous observations which were confined only to fibre cells.

Preformed adventitious root initiation in brittle willows grown in a controlled environment

1970 ◽  
Vol 48 (12) ◽  
pp. 2309-2312 ◽  
Author(s):  
Bruce E. Haissig
Keyword(s):  
Environmental Conditions ◽  
Adventitious Root ◽  
Controlled Environment ◽  
Root Initiation ◽  
Root Primordia ◽  
Initial Formation ◽  
Cellular Physiology ◽  
Secondary Thickening

Nodal preformed adventitious root primordia of brittle willow develop from initial cells which appear first and only in the fourth node below the terminal leaf cluster of plants grown under the described environmental conditions. The onset of root initial formation is related to the cessation of rapid aerial development which occurs at node 4, and also with the start of secondary thickening which occurs in this node. Brittle willow is an ideal subject with which to study the cellular physiology of root initials since nodes showing the earliest stages of root initial formation and development can be selected. In addition, the root initials are readily located in histological preparations.

The developmental anatomy of Conopholis americana (Orobancaceae) seedlings and tubercles

1986 ◽  
Vol 64 (4) ◽  
pp. 710-717 ◽  
Author(s):  
Wm. Vance Baird ◽  
James L. Riopel
Keyword(s):  
Transition Zone ◽  
Tracheary Element ◽  
Cell Types ◽  
Tracheary Elements ◽  
Cortical Cells ◽  
Developmental Anatomy ◽  
Host Root ◽  
Parenchyma Cells ◽  
First Time ◽  
Secondary Vessels

Germinated and attached seedlings of the phanerogamic parasite Conopholis americana (L.) Wallroth are described for the first time. The morphogenetic changes which characterize the transition from seedling to preflowering tubercle, as well as the anatomy of the mature tubercle, including endogenous floral buds, are also described. Conopholis seedlings were found attached only to mycorrhizal oak roots. The primary haustorium attached to and penetrated the fungal sheath, pushing aside epidermal and cortical cells of the host as it grew toward the host stele. Cells of the endophyte contacted host xylem and differentiated directly into reticulately thickened tracheary elements. Concomitantly a cambial are of parasite origin was established within the young tubercle, aligned with the vascular cambium of the host root. The cambium of the tubercle gave rise to xylem centripetally, which differentiated into tracheary elements juxtaposed to host secondary vessels, and cortical parenchyma centrifugally. Sieve elements could not be unequivocally demonstrated in seedlings or tubercles. Tissues and cell types of the parasite could be distinguished from those of the host by both morphological and histochemical criteria. The parasite to host transition zone was characterized by direct tracheary element connections and delimited by densely cytoplasmic parasite parenchyma cells that had greatly enlarged centrally located nuclei.

scholarly journals The Anatomy of the Bark of Agathis in New Zealand

IAWA Journal ◽  
1986 ◽  
Vol 7 (3) ◽  
pp. 229-241 ◽  
Author(s):  
Lek-Lim Chan
Keyword(s):  
New Zealand ◽  
Cell Types ◽  
Cortical Cells ◽  
Phloem Parenchyma ◽  
Sieve Cells ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Long Time ◽  
Crystal Sand ◽  
Resin Canals

The anatomy of the bark of Agathis australis, which is indigenous to New Zealand, is described. The phloem cell types include sieve cells, axial and ray parenchyma, fibres and sclereids. Resin canals are found in the primary cortex, phloem and phelloderm. Large crystals are found in the lumina of some sieve cells and axial parenchyma cells, while minute crystals (crystal sand) are observed in the walls of phe1- loderm cells and complementary tissue cells. The primary cortex persists on the stem for a long time. The shape of phellem and phelloderm cells cut off by phellogen derived from cortical cells are different from those cut off by phellogen derived from phloem parenchyma cells. A trabecula was observed in a radial row of phellem cells.

scholarly journals Development of Inverse Cambia and Structure of Secondary Xylem in Ipomoea turbinata (Convolvulaceae)

2017 ◽  
Vol 62 (1) ◽  
pp. 87-97
Author(s):  
Kishore S. Rajput
Keyword(s):  
Tropical Forests ◽  
Structural Transformation ◽  
Growth Pattern ◽  
Functional Role ◽  
Secondary Xylem ◽  
Experimental Studies ◽  
Secondary Phloem ◽  
Successive Cambia ◽  
Parenchyma Cells

AbstractStructural transformation of mechanical tissues during the shift from a freestanding to a climbing habit is a characteristic of lianas, which are increasingly abundant in tropical forests. The modification of mechanical tissue and the evolution of a new growth pattern serve to increase stem flexibility and conductive efficiency. In Ipomoea turbinata Lag. (Convolvulaceae), the stem thickens via the formation of two distinct types of successive cambia: functionally normal successive cambia (producing xylem centripetally and phloem centrifugally), and inverse cambia (producing xylem centrifugally and phloem centripetally). The former originates from pericyclic derivatives (parenchyma cells located outside the primary phloem), while the latter originates from the conjunctive parenchyma located on the inner margin of the secondary xylem formed from vascular cambium. The secondary xylem produced by normal cambia is significantly more abundant than the xylem formed by inverse cambia. During primary growth, intraxylary primary phloem differentiates concomitantly with the protoxylem at the periphery of the pith; additional intraxylary secondary phloem is added from adjacent parenchyma cells as the plant ages. During initiation of every successive cambium, middle cells in the meristem give rise to cambium, and cells on either side of it serve as sites for initiation of future cambia. The functional role of inverse cambia remains unknown and awaits further experimental studies.

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