Structure of the secondary xylem and development of a cambial variant in Serjania mexicana (Sapindaceae)

IAWA Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Kishore S. Rajput ◽  
Amit D. Gondaliya ◽  
Roger Moya
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
The Family ◽  
Ray Cells ◽  
Cambial Variant ◽  
Proportional Increase ◽  
Plant Families ◽  
Ray Parenchyma Cells ◽  
Cambial Variants

Abstract The lianas in the family Sapindaceae are known for their unique secondary growth which differs from climbing species in other plant families in terms of their cambial variants. The present study deals with the stem anatomy of self-supporting and lianescent habit, development of phloem wedges, the ontogeny of cambial variants and structure of the secondary xylem in the stems of Serjania mexicana (L.) Willd. Thick stems (15–20 mm) were characterized by the presence of distinct phloem wedges and tangentially wide neo-formed cambial cylinders. As the stem diameter increases, there is a proportional increase in the number of phloem wedges and neo-formed vascular cylinders. The parenchymatous (pericyclic) cells external to phloem wedges that are located on the inner margin of the pericyclic fibres undergo dedifferentiation, become meristematic and form small segments of cambial cylinders. These cambia extend tangentially into wide and large segments of neoformations. Structurally, the secondary xylem and phloem of the neo-formed vascular cylinders remain similar to the derivatives produced by the regular vascular cambium. The secondary xylem is composed of vessels (wide and narrow), fibres, axial and ray parenchyma cells. The occurrence of perforated ray cells is a common feature in both regular and variant xylem.

Development of cambial variant and parenchyma proliferation in Hewittia malabarica (Convolvulaceae) from India and South Africa

IAWA Journal ◽  
2020 ◽  
pp. 1-14
Author(s):  
Kishore S. Rajput ◽  
Amit D. Gondaliya ◽  
Himansu Baijnath
Keyword(s):  
South Africa ◽  
Secondary Xylem ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
Histological Techniques ◽  
The Family ◽  
Ray Cells ◽  
Meristematic Activity ◽  
Cambial Variant ◽  
Interxylary Phloem

Abstract Members of the Convolvulaceae are characterized by the climbing habit and occurrence of variant secondary growth. From a histological perspective, the genus Ipomoea L. is the most extensively studied, while other genera have been less studied. Here, stem anatomy of the least studied genus in the family, Hewittia Wight & Arn., represented by Hewittia malabarica (L.) Suresh was investigated using classical histological techniques. In both the samples collected from India and South Africa, stem thickness increased by developing different types of cambial variants such as: neo-formed vascular cylinders, parenchyma proliferation at the phloem wedges, ray-derived cambia from dilating phloem rays, internal cambium, intra- and interxylary phloem. Neo-formed vascular cylinders develop from the parenchyma cells external to the phloem as a meristemoid in thick stems and later in dilating ray cells. With the increase in stem diameter, cells of the phloem wedges showed proliferation by meristematic activity, which form a connection with the cortex by rupturing the primary tissue ring of eustele. Subsequently, development of cambium in phloem wedges and deposition of its derivatives increased the tangential width of rays. Mature thick stems (25–30 mm) give rise to a fissured stem. Intraxylary (internal) phloem development on the pith margin was observed from primary growth onwards and in thick stems secondary intraxylary phloem developed from the internal cambium. Internal cambium is functionally bidirectional and produces secondary xylem internally and secondary phloem externally. In all the samples, patches of unlignified parenchyma embedded within the secondary xylem dedifferentiate and mature into interxylary phloem with the increasing age. Development of cambial variant and structure of the secondary xylem is correlated with the functional significance of the climbing habit.

scholarly journals Development of successive cambia and wood structure in stem of Rivea hypocriteriformis (Convolvulaceae)

2016 ◽  
Vol 61 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Kishore S. Rajput
Keyword(s):  
Secondary Xylem ◽  
Monsoon Season ◽  
Secondary Growth ◽  
Vascular Bundles ◽  
Growth Rings ◽  
Successive Cambia ◽  
Initial Stage ◽  
Ray Cells ◽  
Cell Layers ◽  
Ray Parenchyma Cells

Abstract This study examined the formation of successive rings of cambia in Rivea hypocriteriformis Choisy (Convolvulaceae). The mature stem is composed of four to five rings of xylem alternating with phloem. Successive cambia originate as smaller and larger segments; union and anastomosing of small cambial segments often leads to the formation of discontinuous rings. In the initial stage of growth, several vascular bundles interconnect to form the first ring of vascular cambium. The cambium remains functional for one complete season and becomes dormant during summer; a new ring of cambium is completed prior to the subsequent monsoon season and sprouting of new leaves. Successive cambia are initiated from the pericyclic parenchyma situated three to four cell layers outside of the protophloem. Functionally, all the successive cambia are bidirectional and produce secondary xylem centripetally and phloem centrifugally. The secondary xylem is diffuse-porous, with indistinct growth rings and consisting of wide fibriform vessels, fibre tracheids, and axial and ray parenchyma cells. The xylem rays are uni- to multiseriate and heterocellular. The multiseriate rays contain lignified marginal ray cells and thin-walled, unlignified central cells. The central ray cells also show accumulations of starch and druses. Discrete strands of intraxylary phloem occur at the periphery of the pith, and additional intraxylary phloem develops from adjacent cells as secondary growth progresses. Earlier-formed phloem shows heavy accumulation of callose, followed by its compaction. The development of successive cambia is correlated with extension growth and with the phenology of the plant.

Stem anatomy at various developmental stages of secondary growth in Turbina corymbosa (Convolvulaceae)

2018 ◽  
Vol 151 (2) ◽  
pp. 219-230 ◽  
Author(s):  
Manoj M. Lekhak ◽  
Amit D. Gondaliya ◽  
Shrirang R. Yadav ◽  
Kishore S. Rajput
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Growth Patterns ◽  
Stem Anatomy ◽  
Successive Cambia ◽  
Background Population ◽  
Short Period ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Background – Population growth of lianas in the tropical forest is credited to their ability of CO2 sequestration and efficiency of the narrow stems to supply water required for the amount of foliage it bears. Turbina corymbosa (L.) Raf. (Convolvulaceae Juss.) is one of the fast-growing invasive species of scrambling woody lianas. It covers trees entirely within a short period to compete with above-ground resources (particularly sunlight). However, no information is available on how it manages to cope up with an increasing demand of water supply and mineral nutrients. What are the structural and developmental patterns adapted by this species to expand the stem diameter for efficient supply of below-ground resources? Therefore, our aim was to investigate the secondary growth patterns and structure of secondary xylem and phloem in T. corymbosa.Methods – Several samples of the stem with various diameters were studied using a histological method. Morphological and anatomical analyses were carried out using light microscopy.Key results – With the initiation of secondary growth, stems lose their circular outline rapidly due to unequal deposition of secondary xylem and formation of successive cambia. New successive cambia initiate from parenchymatous cells as small crescent-shaped fragments on asymmetric/opposite sides and result in a different stem conformation. Though several segments of successive cambia are formed, very few stem samples form complete cambium rings. The secondary xylem formed by successive cambia is diffuse porous with indistinct growth rings and is composed of both wide and narrow (fibriform) vessels, tracheids, fibres, axial and ray parenchyma cells. The secondary phloem consists of sieve tube elements, companion cells, axial and ray parenchyma cells. In fully grown plants, cambial action (internal cambium) occurrs between the intraxylary phloem and protoxylem and produces secondary xylem and phloem near the pith region.Conclusion – Structural alterations and unequal deposition of conducting elements, occurrence of intraxylary phloem and flattening of the stem are suggested to facilitate rapid growth of the plants by providing required minerals and nutrients. Internal cambium formed at the periphery of the pith is bidirectional and produces secondary xylem externally and intraxylary phloem internally. Continued development of intraxylary phloem from the internal cambium provides an additional path for rapid and safe translocation of photosynthates.

Structure and ontogeny of the fissured stems of Callaeum (Malpighiaceae)

IAWA Journal ◽  
2017 ◽  
Vol 38 (1) ◽  
pp. 49-66 ◽  
Author(s):  
Pablo A. Cabanillas ◽  
Marcelo R. Pace ◽  
Veronica Angyalossy
Keyword(s):  
Secondary Xylem ◽  
Vascular System ◽  
Secondary Growth ◽  
Natural Fracture ◽  
Production Rates ◽  
Axial Parenchyma ◽  
Parenchyma Cells ◽  
Ray Cells ◽  
Cambial Variant ◽  
Stem Development

Stem ontogeny and structure of two neotropical twining vines of the genus Callaeum are described. Secondary growth in Callaeum begins with a typical regular cambium that gradually becomes lobed as a result of variation in xylem and phloem production rates in certain portions of the stem aligned with stem orthostichies. As development progresses, lignified ray cells of the initially formed secondary xylem detach on one side from the adjacent tissues, forming a natural fracture that induces the proliferation of both ray and axial nonlignified parenchyma. At the same time, parenchyma proliferation takes place around the pith margin and generates a ring of radially arranged parenchyma cells. The parenchyma generated in this process (here termed disruptive parenchyma) keeps dividing throughout stem development. As growth continues, the parenchyma finally cleaves the lignified axial parts of the vascular system into several isolated fragments of different sizes. Each fragment consists of xylem, phloem and vascular cambium and is immersed in a ground matrix of disruptive parenchyma. The cambium present in each fragment divides anticlinally to almost encircle each entire fragment and maintains its regular activity by producing xylem to the centre of the fragment and phloem to the periphery. Additionally, new cambia arise within the disruptive parenchyma and produce xylem and phloem in various polarities, such as xylem to the inside and phloem to the outside of the stem, or perpendicularly to the original cambium. Unlike the very distinctive stem anatomical architecture resulting from this cambial variant in Callaeum, its secondary xylem and phloem exhibit features typical of lianas. These features include very wide conducting cells, abundant axial parenchyma, high and heterocellular rays and gelatinous fibres.

scholarly journals Linking the Evolution of Development of Stem Vascular System in Nyctaginaceae and Its Correlation to Habit and Species Diversification

2021 ◽  
Author(s):  
Israel L. Cunha Neto ◽  
Marcelo Rodrigo Pace ◽  
Rebeca Hernández-Gutiérrez ◽  
Veronica Angyalossy
Keyword(s):  
Developmental Stages ◽  
Vascular System ◽  
A Priori ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
Species Diversification ◽  
Successive Cambia ◽  
The Family ◽  
Interxylary Phloem ◽  
Cambial Variants

Abstract Background: The presence of alternative patterns of secondary growth in stems of Nyctaginaceae has been known for a long time. Still, the interpretation of types of cambial variants are controversial. The knowledge on stem anatomical diversity in Nyctaginaceae, which is diverse also in habits, offers the unique opportunity not only to investigate the evolution of complex developments, but also to address how these anatomies shifted within habits and how the acquisition of novel cambial variants and habit transitions impacted the diversification of the family. Methods: We integrated developmental data with a phylogenetic framework to investigate the diversity and evolution of stem anatomy in Nyctaginaceae using phylogenetic comparative methods, reconstructing ancestral states, and examining whether anatomical shifts correspond to species diversification rate shifts in the family. Results: Two types of cambial variants, interxylary phloem and successive cambia, were recorded in Nyctaginaceae, which result from four different ontogenies. These ontogenetic trajectories depart from two distinct primary vascular structures (regular or polycyclic eustele) yet, they contain shared developmental stages which generate stem morphologies with deconstructed boundaries of morphological categories (continuum morphology). Unlike our a priori hypotheses, interxylary phloem is reconstructed as the ancestral character for the family, with three ontogenies characterized as successive cambia evolving in few taxa. Cambial variants are not contingent in habits, and their transitions are independent from species diversification.Conclusions: Our findings suggests that multiple developmental mechanisms, such as heterochrony and heterotopy generate the transitions between interxylary phloem and successive cambia. Intermediate between these two extremes are present in Nyctaginaceae, suggesting a continuum morphology across the family as a generator of anatomical diversity.

scholarly journals The stem anatomy of the Clematis species (Ranunculaceae) in Taiwan

2021 ◽  
Author(s):  
Sheng-Zehn Yang ◽  
Po-Hao Chen ◽  
Chien-Fan Chen
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Restriction Pattern ◽  
Vascular Bundles ◽  
Stem Anatomy ◽  
Primary Xylem ◽  
Morphological Studies ◽  
Arc Shape ◽  
Key Features ◽  
Cambial Variants

Abstract Background Studies on the stem anatomical characteristics of Taiwanese species from the Clematis genus (Ranunculaceae) are scarce. This study aimed to investigate and compare the patterns of secondary growth in stems of 22 Clematis species. Results The rhytidome is composed of periderm and non-conducting phloem and formed either cogwheel-like or continuous segment bark. Key features of the genus were stem with an irregular conformation, wedge-like phloem and rays, indentations in the axial parenchyma, ray dilatation, and narrow rays. Approximately eight Clematis species formed bark arc shape, which developed the cogwheel- like rhytidome. There were with approximately 27% of the Clematis species in Taiwan having 12 vascular bundles. The vessels dispersed throughout the stem were semi-ring-porous in most species but were ring-porous in others. No species had diffuse-porous vessels. The vessel restriction pattern was only found in the two shrubs, C. psilandra and C. tsugetorum. The primary xylem ring was located around the pith in C. uncinata var. uncinata, making its pith cavity hexagon in shape. Four species had the pith cavity feature. Narrow rays that occurred in the secondary xylem increased with increasing stem diameter. Conclusions The cambial variants described in this study provide a foundation for further morphological studies of the Clematis genus.

Traumatic Gum-Resin Cavities in the Stem of Ailanthus Excelsa Roxb.

IAWA Journal ◽  
1987 ◽  
Vol 8 (2) ◽  
pp. 167-174 ◽  
Author(s):  
A.M. Babu ◽  
G.M. Nair ◽  
J.J. Shah
Keyword(s):  
Epithelial Cells ◽  
Secondary Xylem ◽  
Ailanthus Excelsa ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Cells ◽  
Cell Layers ◽  
Ethephon Treatment ◽  
Xylem Elements ◽  
Ray Parenchyma Cells

Traumatic gum-resin cavities develop in the secondary xylem of the stem of Ailanthus excelsa Roxb. in response to fungal infection and ethephon treatment. After infection or ethephon treatment, traumatic parenchyma in several cell layers develops instead of normal secondary xylem elements. It consists of unlignified axial and ray parenchyma cells. Vessels and fibres are absent. Gum-resin cavities in one or two tangential rows develop in this tissue by the lysis of its axial parenchyma cells. The cavities are bordered by an epithelium. A few layers of traumatic parenchyma cells adjacent to the epithelial cens become meristematic and appear cambiform. The epithelial cells undergo lysis and they evidently contribute to gum-resin formation. As the lysis of epithelial cens proceeds, the adjacent cambiform cens divide to form additional epithelial cells. The process continues for some time and eventually an the axial cells of the traumatic parenchyma break down forming a tangentially anastomosing network of cavities. The cavities do not traverse the ray cells, and the multiseriate rays remain intact like bridges amidst the ramifying cavities.

MENISPERMACEAE WOOD ANATOMY AND CAMBIAL VARIANTS

IAWA Journal ◽  
2007 ◽  
Vol 28 (2) ◽  
pp. 139-172 ◽  
Author(s):  
Frédéric M.B. Jacques ◽  
Dario De Franceschi
Keyword(s):  
Wood Anatomy ◽  
Secondary Growth ◽  
Successive Cambia ◽  
General Overview ◽  
The Family ◽  
Growth Types ◽  
Perforation Plates ◽  
Cambial Variants

Menispermaceae are comprised almost entirely of lianas. Study of its wood anatomy is of interest for understanding adaptation to the liana habit. We set out here to present a general overview of Menispermaceae wood. The wood anatomy of 77 species of 44 genera, representative of an tribes and from an continents, is described. The wood of 18 of these genera was previously unknown. We observed two secondary growth types within the family: wood with successive cambia and wood with a single cambium. The distribution of these types is partly consistent with the c1assification of the family by Diels. General characters of the family are: wide rays, enlarged vessel pits near the perforation plates, and pitted tyloses. The fun range of wood anatomical diversity is given in Table 1.

scholarly journals Development of Intra- and Interxylary Secondary Phloem in Coccinia indica (Cucurbitaceae)

IAWA Journal ◽  
2011 ◽  
Vol 32 (4) ◽  
pp. 475-491 ◽  
Author(s):  
Vidya S. Patil ◽  
Carmen R. Marcati ◽  
Kishore S. Rajput
Keyword(s):  
Vascular Bundle ◽  
Secondary Xylem ◽  
Secondary Growth ◽  
Cambial Activity ◽  
Vascular Bundles ◽  
Secondary Phloem ◽  
Stem Anatomy ◽  
Axial Parenchyma ◽  
Vessel Elements ◽  
Coccinia Indica

Stem anatomy and the development of intraxylary phloem were investigated in six to eight years old Coccinia indica L. (Cucurbitaceae). Secondary growth in the stems was achieved by the normal cambial activity. In the innermost part of the thicker stems, xylem parenchyma and pith cells dedifferentiated into meristematic cells at several points. In some of the wider rays, ray cells dedifferentiate and produce secondary xylem and phloem with different orientations and sometimes a complete bicollateral vascular bundle. The inner cambial segments of the bicollateral vascular bundle (of primary growth) maintained radial arrangement even in the mature stems but in most places the cambia were either inactive or showed very few cell divisions. Concomitant with the obliteration and collapse of inner phloem (of bicollateral vascular bundles), parenchyma cells encircling the phloem became meristematic forming a circular sheath of internal cambia. These internal cambia produce only intraxylary secondary phloem centripetally and do not produce any secondary xylem. In the stem, secondary xylem consisted mainly of axial parenchyma, small strands of thick-walled xylem derivatives, i.e. vessel elements and fibres embedded in parenchymatous ground mass, wide and tall rays along with exceptionally wide vessels characteristic of lianas. In thick stems, the axial parenchyma de-differentiated into meristem, which later re-differentiated into interxylary phloem. Fibre dimorphism and pseudo-vestured pits in the vessels are also reported.

Stem Anatomy and Development of Successive Cambia in the Neotropical Liana Securidaca Rivinifolia (Polygalaceae)

IAWA Journal ◽  
2012 ◽  
Vol 33 (4) ◽  
pp. 391-402 ◽  
Author(s):  
Kishore S. Rajput ◽  
Marina B. Fiamengui ◽  
Carmen R. Marcati
Keyword(s):  
Secondary Xylem ◽  
Secondary Growth ◽  
Stem Anatomy ◽  
Growth Rings ◽  
Cross Sectional ◽  
Axial Parenchyma ◽  
Successive Cambia ◽  
Bordered Pits ◽  
Perforation Plates ◽  
Diffuse Porous

The pattern of secondary growth and structure of secondary xylem was studied in the stem of the Neotropical liana Securidaca rivinifolia A. St.-Hil. (Polygalaceae). Increase in thickness of the stem was achieved by formation of successive cambia, from which initially two or three successive rings formed complete oval to circular cambia. Thereafter, the successive cambia were always crescent-shaped and never formed a complete cylinder, resulting in dumbbell-shaped cross-sectional outlines of the stems. The first successive cambium originated in the pericyclic parenchyma located outside the crushed protophloem. Prior to the development of cambium, pericyclic parenchyma formed a meristematic band of radially arranged cells. From this band, cells located in the middle of the band became the new ring of cambium. Cells on the inner face of the xylem produced by newly formed cambium differentiated into conjunctive tissue. The first elements to be differentiated from the newly developed cambium were always xylem fibres but differentiation of vessels was also observed occasionally. The xylem was diffuse porous with relatively distinct growth rings and composed of mostly solitary vessels with simple perforation plates, fibres with bordered pits, paratracheal axial parenchyma, and exclusively uniseriate rays.

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