Wood and Stem Anatomy of Stegnosperma (Caryophyllales); Phylogenetic Relationships; Nature of Lateral Meristems and Successive Cambial Activity

IAWA Journal ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 149-163 ◽  
Author(s):  
Sherwin Carlquist

Wood and bark histology data on stems of two species of Stegnospenna (Stegnospermataceae, or Phytolaccaceae s.l.) is presented, complementing previous accounts . Wood of Stegnosperma is relatively primitive within Caryophyllales because of presence of tracheids , diffuse parenchyma, and both multiseriate and uniseriate rays . The solitary nature of vessels is held to be correlated with tracheid presence , as in other groups of dicotyledons with vessels solitary or nearly so. Bark anatomy is newly reported for the genus . The method of section used permits analysis of divisions in cells with primary walls. Radial rows of parenchyma ('secondary cortex') develop in the inner cortex and are perpetuated by tangential divisions collectively termed a diffuse lateral meristem here. Successive cambia form within the radial rows of parenchyma. Despite diverse terminology and interpretations in literature on plants with successive cambia, the successive cambia and their origin in Stegnosperma are believed to represent the same anatomical phenomena as in other Phytolaccaceae s.l.

IAWA Journal ◽  
1999 ◽  
Vol 20 (4) ◽  
pp. 431-440 ◽  
Author(s):  
Sherwin Carlquist

Liquid-preserved material of mature sterns of Barbeuia madagascariensis Steud. permiUed analysis of meristematic activities. The species has successive cambia, each producing secondary xylem and phloem; outside of these vascular strands is a nondiffuse lateral meristem, probably functionally a single cell in thickness, which produces radial files of secondary cortex to the outside and conjunctive tissue and vascular cambia to the inside. The secondary xylem of Barbeuia has dimorphism in vessel diameter, reminiscent of vessel dimorphism in other lianas, such as Agdestis. Diffuse parenchyma and tracheids, found in Barbeuia, also occur in Stegnosperma and Agdestis but not other Phytolaccaceae s.l., and are traditionally considered primitive features. Wood anatomy and lateral meristem activity of Barbeuia are distinctive enough to support segregation of the genus from Phytolaccaceae s. s.


Phytotaxa ◽  
2016 ◽  
Vol 280 (3) ◽  
pp. 241 ◽  
Author(s):  
CAROLINA ANGÉLICA ARAÚJO DE AZEVEDO ◽  
VALÉRIA CASSANO ◽  
MARIANA CABRAL OLIVEIRA

Phylogenetic relationships and species diversity within the genus Halymenia along the Brazilian coast were investigated through molecular and morphological analyses. Molecular studies included UPA, COI-5P and rbcL markers. A total of five Halymenia species were found: Halymenia cearensis sp. nov., H. ignifera, H. pinnatifida, H. silviae and H. cf. mirabilis. Halymenia cearensis was molecularly distinct from all other Halymenia species included in this study and is morphologically characterized by: cleft, lobate, oblong or obovate blades with broad base; apex irregular in shape; surface with bullations, rugosities, spiny and globular papillae irregularly distributed; abundant and conspicuous ganglionic cells throughout; blades up to 800 µm thick at base; outer cortical cells ellipsoidal or ovoid in shape, higher than broad; and inner cortex cells 4–25 µm in width. Our phylogeny demonstrated that entities attributed to H. floridana and H. elongata occurring in Brazil correspond to two distinct genera, which was also supported by morphological and ecological data. The use of molecular tools was crucial to provide a better understanding of the diversity of Brazilian marine flora.


2018 ◽  
Vol 151 (2) ◽  
pp. 219-230 ◽  
Author(s):  
Manoj M. Lekhak ◽  
Amit D. Gondaliya ◽  
Shrirang R. Yadav ◽  
Kishore S. Rajput

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.


IAWA Journal ◽  
2001 ◽  
Vol 22 (2) ◽  
pp. 171-181 ◽  
Author(s):  
Sherwin Carlquist

Qualitative and quantitative data are given for two species of Rhabdodendron. Newly reported for wood of the family are vestured pits in vessels and tracheids, nonbordered perforation plates, abaxial axial parenchyma, and presence of sphaerocrystals. Although treated variously in phylogenetic schemes, Rhabdodendron is placed in an expanded Caryophyllales in recent cladograms based on molecular data. This placement is consistent with features characteristic of most families of the order, such as nonbordered perforation plates and successive cambia. Primitive character states in Rhabdodendron (tracheids, diffuse axial parenchyma, ray type) are shared with Caryophyllales s.l. that branch near the base of the clade: Agdestis, Barbeuia, Simmondsia, and Stegnosperma. Presence of vestured pits in vessels and silica bodies in wood, features not reported elsewhere in Caryophyllales s.l., are shared by Rhabdodendron and Polygonaceae. Wood of Rhabdodendron has no features not found in other Caryophyllales, and is especially similar to genera regarded as closely related to it in recent phylogenetic hypotheses. Successive cambia that are presumably primitive in the clade that includes Rhabdodendron are discussed. Distinctions between sphaerocrystals and druses are offered.


IAWA Journal ◽  
1997 ◽  
Vol 18 (3) ◽  
pp. 215-228 ◽  
Author(s):  
Guillermo Angeles ◽  
Calixto León-Gómez

Bark anatomy of four species of Vitaceae growing at the tropical rain forest of Veracruz, Mexico, is described. Young and mature individuals were collected at the tropical biology field station 'Los Tuxtlas' . External, gross characteristics of the bark and microscopic features of young and adult individuals are given. Sectorization of the vascular tissues into minor and major areas was found in the three Cissus species, but not in Vitis tiliifolia, where it was apparent only at early stages of development. All the species studied have storied secondary phloem and very tall rays. The potential role of mucilage in water-holding capacity and the relationship of stem anatomy and aerial root formation are discussed.


2021 ◽  
Author(s):  
Israel L. Cunha Neto ◽  
Marcelo Rodrigo Pace ◽  
Rebeca Hernández-Gutiérrez ◽  
Veronica Angyalossy

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.


2018 ◽  
Vol 143 (1) ◽  
pp. 67-71
Author(s):  
Huan-Keng Lin ◽  
Tzu-Yao Wei ◽  
Chin-Mu Chen ◽  
Der-Ming Yeh

Stem anatomy and modulus of elasticity (MOE) were compared between upright and trailing cultivars of periwinkle [Catharanthus roseus (G.) Don.]. The inheritance of growth habit and flower form was also studied. Internode cross sections revealed that phloem fiber was distributed at the inner cortex in upright cultivars but not in trailing cultivars. Except the youngest internode, the upright ‘Vitesse Pink’ had the highest MOE throughout the 1st–13th internodes above the cotyledon. The more trailing ‘Cora Cascade Strawberry’ had consistently lower MOE than a less trailing ‘Cora Cascade Polka Dot’. All F1 plants between upright and trailing cultivars were upright, and the F2 generation derived from self-pollinating F1 fit a 3 upright : 1 trailing segregation ratio. All F1 plants between upright/double-flower and trailing/single-flower exhibited upright and single-flowers, whereas plants in the F2 generation fitted a 9 upright/single-flower : 3 trailing/single-flower : 3 upright/double-flower : 1 trailing/double-flower ratio. New double-flowered periwinkle selections with trailing growth habit were successfully developed from the F2 population.


IAWA Journal ◽  
2011 ◽  
Vol 32 (4) ◽  
pp. 475-491 ◽  
Author(s):  
Vidya S. Patil ◽  
Carmen R. Marcati ◽  
Kishore S. Rajput

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.


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