scholarly journals Development of Successive Cambia and Structure of Secondary Xylem of Ipomoea Obscura (Convolvulaceae)

2014 ◽  
Vol 59 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Kishore S. Rajput ◽  
Bharat D. Chaudhary ◽  
Vidya S. Patil
Keyword(s):  
Secondary Xylem ◽  
Vascular Bundles ◽  
Growth Rings ◽  
Sieve Elements ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Thin Walled ◽  
Ray Parenchyma Cells ◽  
Ipomoea Obscura

Abstract Stems of Ipomoea obscura Ker Gawl., increase in thickness by forming multiple rings of cambia. Stems 5-6 mm thick produce parenchymatous derivatives which divide repeatedly to form small arcs of cambium. Several such small arcs initiate simultaneously and form a ring of small cambial arcs. After the formation of a few xylem and phloem elements, all these arcs are interconnected by transdifferentiation of parenchyma cells present between the cambial arcs and constitute a complete cambial cylinder. This newly formed cambium is functionally bidirectional: earlier- formed arcs produce xylem centripetally and phloem centrifugally, while later-formed segments exclusively produce thin-walled parenchyma cells on either side. Young stems are circular in cross section but as stem thickness increases they become oval to elliptic or lobed and dumbbell-shaped. Xylem rays are mostly uni- or biseriate and thin-walled, but multiseriate rays characteristic for a climbing habit are observed occasionally. In thick stems, the marginal ray parenchyma in most of the samples becomes meristematic and develops ray cambia which exclusively produce sieve elements. Similarly, parenchyma cells produced from later-formed cambial segments give rise to several irregularly oriented vascular bundles. The secondary xylem is diffuse porous, with indistinct growth rings and is composed of fibriform and wider vessels, fibres, and axial and ray parenchyma cells, while phloem consists of sieve elements, companion cells, and axial and ray parenchyma cells.

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.

FORMATION OF SUCCESSIVE CAMBIA IN THE MENISPERMUM TREE COCCULUS LAURIFOLIUS (MENISPERMACEAE)

IAWA Journal ◽  
2015 ◽  
Vol 36 (4) ◽  
pp. 400-408 ◽  
Author(s):  
Kishore S. Rajput ◽  
Sangeeta Gupta
Keyword(s):  
Cell Division ◽  
Tree Species ◽  
Secondary Xylem ◽  
Vessel Diameter ◽  
Outer Side ◽  
Successive Cambia ◽  
Meristematic Cells ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Successive cambia are often associated with the climbing or shrub habit, and is less common in trees. We studied formation of successive cambia and structure of secondary xylem in young stems of Cocculus laurifolius DC., a tree species of Menispermaceae. Cell division in the vascular cambium ceased in pencil-thick stems. Subsequently, parenchyma cells located outside the perivascular fibre cap re-differentiated and gave rise to several small segments of meristematic cells, of which the central cells divided repeatedly to initiate the first successive cambium which produces secondary xylem centripetally and phloem centrifugally. Cells located on the inner side of the newly initiated cambium differentiated into conjunctive tissue while cells on the outer side of it divided further and differentiated into sclereids. Xylem was diffuse porous and composed of vessels, fibre tracheids and ray parenchyma cells, and only differed in vessel diameter from wide-vessel climbing relatives.

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.

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.

WOOD ANATOMY OF MYRCIARIA, NEOMITRANTHES, PLINIA AND SIPHONEUGENA SPECIES (MYRTEAE, MYRTACEAE)

IAWA Journal ◽  
2013 ◽  
Vol 34 (3) ◽  
pp. 313-323 ◽  
Author(s):  
Gabriel U.C.A. Santos ◽  
Cátia H. Callado ◽  
Marcelo da Costa Souza ◽  
Cecilia G. Costa
Keyword(s):  
Wood Anatomy ◽  
Growth Rings ◽  
Anatomical Features ◽  
Bordered Pits ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Square Cells ◽  
Ray Parenchyma Cells ◽  
Perforation Plates ◽  
Fruit Characters

Myrciaria, Neomitranthes, Plinia and Siphoneugena are closely related genera whose circumscriptions are controversial. The distinctions between Myrciaria vs. Plinia, and Neomitranthes vs. Siphoneugena, have been based on a few fruit characters. The wood anatomy of 24 species of these genera was examined to determine if wood anatomical features could help delimit the genera. It was determined the four genera cannot reliably be separated by wood anatomy alone. Characteristics seen in all four genera are: growth rings usually poorly-defined; diffuse porous; exclusively solitary vessels, usually circular to oval in outline; simple perforation plates; vessel-ray pits alternate and distinctly bordered; fibers with distinctly bordered pits in radial and tangential walls, usually very thickwalled; vasicentric tracheids typically absent; scanty paratracheal parenchyma, sometimes unilateral, and diffuse to diffuse-in-aggregates; chambered crystalliferous axial parenchyma in many species, usually both prismatic and smaller crystals; rays 1–4-seriate, uniseriate rays composed of upright/square cells, multiseriate rays with procumbent body cells and 1 to many marginal rows of upright/square cells; disjunctive ray parenchyma cells usually present.

Vertical and Radial Variation of Nuclear Elongation Index of Living Sapwood Ray Parenchyma Cells in a Plantation Tree of Cryptomeria Japonica

IAWA Journal ◽  
1994 ◽  
Vol 15 (3) ◽  
pp. 323-327 ◽  
Author(s):  
K.C. Yang ◽  
Y.S. Chen ◽  
C.A. Benson
Keyword(s):  
Metabolic Activity ◽  
Cryptomeria Japonica ◽  
Ground Level ◽  
Tree Crown ◽  
Growth Rings ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Cells ◽  
Elongation Index ◽  
Ray Parenchyma Cells

Vertical and radial variations of nuclear elongation index (NEI) of living sapwood ray parenchyrna cells were studied in a 45-year-old plantation tree of Cryptomeria japonica D. Don collected in Taiwan on February 27, 1992. Nine wood strips oriented in an E-W direction of the tree were collected starting at 0.3 m above ground level, and progressing upwards by 2.5 m intervals to the tree crown. Radial sections, 20 µm thick, were cut from the cambium toward the inner sapwood of these nine wood strips. The nuclear elongation index (NEI) was used to express the metabolic activity of the ray cells. It was found that metabolic activity of sapwood ray parenchyma was thc highest at the outer sapwood and declined gradually towards the inner sapwood. The lowest average NEI was found at the lowest stern level. The average NEI of various stern height levels increased with increasing stern height level. The average NEI of three growth rings at the outer sapwood near the cambium reached a maximum at the bottom of the live crown.

DISTRIBUTION AND VITALITY OF XYLEM RAYS IN RELATION TO TREE LEAF AREA IN DOUGLAS-FIR

IAWA Journal ◽  
2000 ◽  
Vol 21 (4) ◽  
pp. 389-401 ◽  
Author(s):  
Barbara L. Gartner ◽  
David C. Baker ◽  
Rachel Spicer
Keyword(s):  
Leaf Area ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Relative Volume ◽  
Growth Rings ◽  
Breast Height ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells ◽  
Tree Leaf

The factors that determine sapwood width and volume in a tree are not known. This study asked whether sapwood width is related to a need for stem storage sites. Experiments were conducted on 12 34-year-old Douglas-fir [(Pseudotsuga menziesii (Mirb.) Franco] trees with a 6-7 fold range of leaf areas and leaf area/sapwood volumes. Because of declining ray frequency but constant average ray area, ray volume declined for the first 6-10 growth rings, then remained constant, and did not vary with height (breast height vs. 10 nodes from the top). Fewer of the ray parenchyma cells had nuclei in inner than outer sapwood. Inner sapwood had ray parenchyma with smaller rounder nuclei than did outer sapwood, and there was no effect of height. There was a positive relationship between leaf area and the relative volume of ray in outer sapwood at breast height (r = 0.646, p = 0.02), supporting the hypothesis that Douglas-fir trees with larger leaf areas have higher ray volume than do trees with smaller leaf areas. However, correlations of leaf area I sapwood volume with leaf area at either height were not significant, nor were correlations of either leaf area or leaf area/sapwood volume with measures of ray vitality (nuclear frequency in outer sapwood, or the ratio of nuclear frequency in the middle I outer sapwood or in inner I outer sapwood). These latter correlations give no evidence that Douglas-fir trees determine their sapwood volume based on a need for quantity of vital xylem rays.

scholarly journals How Long Do Wood Parenchyma Cells Live in the Stem of a Scots Pine (Pinus sylvestris L.)? Studies on Cell Nuclei Status along the Radial and Longitudinal Stem Axes

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 977 ◽  
Author(s):  
Mirela Tulik ◽  
Joanna Jura-Morawiec ◽  
Anna Bieniasz ◽  
Katarzyna Marciszewska
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Apical Meristem ◽  
Uv Light ◽  
Cell Nuclei ◽  
Growth Rings ◽  
Axial Parenchyma ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

This paper deals with the spatial distribution of heartwood in Scots pine stems (Pinus sylvestris L.), determined on the basis of the absence of nuclei in parenchyma cells. Samples were collected at several heights from two Scots pine stems growing in fresh coniferous stand as codominant trees. Transverse and radial sections were cut from the samples and stained with acetocarmine to detect the nuclei and with I2KI to show starch grains. Unstained sections were also observed under ultraviolet (UV) light to reveal cell wall lignification. The shapes of the nuclei in ray and axial parenchyma cells differed: the axial parenchyma cells had rounded nuclei, while the nuclei of the ray parenchyma cells were elongated. The lifespan of the parenchyma cells was found to be 16–42 years; the longest-lived were cells from the base of the stem, and the shortest-lived were from the base of the crown. The largest number of growth rings comprising heartwood was observed at a height of 1.3–3.3 m, which signifies that the distribution of heartwood within the stem is uneven. Moreover, the distance of the cells from the apical meristem and the cambium was seen to have an effect on the presence of living parenchyma cells, i.e., those with stained nuclei.

Aggregate Rays of Thujopsis Dolabrata Var. Hondai (Cupressaceae)

IAWA Journal ◽  
1993 ◽  
Vol 14 (3) ◽  
pp. 315-323 ◽  
Author(s):  
Toyonobu Sugawa ◽  
Tomoyuki Fujii
Keyword(s):  
Irregular Shape ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Thin Walled ◽  
Ray Parenchyma Cells

Aggregate rays of Thujopsis dolabrata Sieb. et Zucc. var. hondai are described in detail. These rays occur sporadically in Thujopsis stemwood and are composed mainly of multiseriate rays, with thin-walled ray parenchyma cells, and ray tracheids of irregular shape and widely varying size. Ray tracheids have Iignified three-layered secondary walls, but their S3 layer is very thin as in the secondary walls of axial tracheids.

scholarly journals Structure and development of cortical bundles in Couroupita guianensis Aubl. (Lecythidaceae)

2016 ◽  
pp. 95-102
Author(s):  
Kishore Shankarsinh Rajput ◽  
Vidya Shivram Patil
Keyword(s):  
Apical Meristem ◽  
Secondary Xylem ◽  
Vascular Bundles ◽  
Flower Bud ◽  
Couroupita Guianensis ◽  
Vascular Elements ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Three Bundles ◽  
Sieve Tubes

El desarrollo de haces corticales, en ramas y pedúnculos de Couroupita guianensis (Lecythidaceae), comienza cerca del meristemo apical concomitante con los haces vasculares normales. Cada haz cortical llega a estar rodeado por una vaina de fibras que, a menudo, mostraba la presencia de una capa gelatinosa (fibras G). A medida que avanza el crecimiento, cada haz se puede dividir en dos o tres haces. Algunos de los haces son mayores y muestran elementos vasculares bien diferenciados debido a su asociación con frutos en desarrollo, mientras que los más pequeños, con pocos vasos, pueden ser trazas foliares o de yemas de flores que caen antes de la fecundación. El xilema secundario del haz cortical está compuesto de vasos, fibras y células del parénquima axial, mientras que el floema consiste en tubos cribosos, células de acompañamiento y células del parénquima axial.The development of cortical bundles, in the branches and peduncles of Couroupita guianensis (Lecythidaceae), initiates close to the apical meristem concomitant with the normal vascular bundles. Each cortical bundle becomes surrounded by a sheath of fibres, which most often showed presence of gelatinous layer (G-fibres). As growth progresses, theses bundle may divide into two-three bundles. Some of the bundles are larger and show well differen­tiated vascular elements due to their association with developing fruits while narrower bundles, with few vessels, may be leaf traces or flower bud traces that fell down before fertilization. The secondary xylem of cortical bundle is composed of vessels, fibres and a­xial parenchyma cells while phloem consists of sieve tubes, companion cells and axial parenchyma cells.

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