scholarly journals Conducting tissues and phyletic relationships of bryophytes

2000 ◽  
Vol 355 (1398) ◽  
pp. 795-813 ◽  
Author(s):  
R. Ligrone ◽  
J. G. Duckett ◽  
K. S. Renzaglia
Keyword(s):  
Long Distance ◽  
Sieve Cells ◽  
Parenchyma Cells ◽  
Cytoplasmic Organization ◽  
Symplasmic Transport ◽  
Axial System ◽  
Similar Organization

Internal specialized conducting tissues, if present, are restricted to the gametophytic generation in liverworts while they may occur in both generations in mosses. Conducting tissues are unknown in the anthocerotes. Water–conducting cells (WCCs) with walls perforated by plasmodesma–derived pores occur in the Calobryales and Pallaviciniaceae (Metzgeriales) among liverworts and in Takakia among mosses. Imperforate WCCs (hydroids) are present in bryoid mosses. A polarized cytoplasmic organization and a distinctive axial system of microtubules is present in the highly specialized food–conducting cells of polytrichaceous mosses (leptoids) and in less specialized parenchyma cells of the leafy stem and seta in other mosses including Sphagnum . A similar organization, suggested to reflect specialization in long–distance symplasmic transport of nutrients, also occurs in other parts of the plant in mosses, including rhizoids and caulonemata, and may be observed in thallus parenchyma cells of liverworts. Perforate WCCs in the Calobryales, Metzgeriales and Takakia , and hydroids in bryoid mosses, probably evolved independently. Because of fundamental differences in developmental design, homology of any of these cells with tracheids is highly unlikely. Likewise, putative food–conducting of bryophytes present highly distinctive characteristics and cannot be considered homologous with the sieve cells of tracheophytes.

Anatomy and Chemical Composition of Pinus Pinaster Bark

IAWA Journal ◽  
1996 ◽  
Vol 17 (2) ◽  
pp. 141-150 ◽  
Author(s):  
Elsa Nunes ◽  
Teresa Quilhó ◽  
Helena Pereira
Keyword(s):  
Chemical Composition ◽  
Pinus Pinaster ◽  
Variable Number ◽  
Starch Granules ◽  
Secondary Phloem ◽  
Scale Type ◽  
Resin Ducts ◽  
Sieve Cells ◽  
Parenchyma Cells

The secondary phloem of Pinus pinaster Aiton bark has sieve cells and axial and radial parenchyma, but no fibres. Resin ducts are present in fusiform rays . Stiloid crystals, starch granules and tannins occur inside sieve and parenchyma cells. The rhytidome of P. pinaster bark has a variable number of periderms forming scale-type discontinuous layers over expanded parenchyma cells. Phellem comprises 4-6 layers of thickwaIled and little suberized cells and phelloderm a layer of 2 or 3 thickened lignified ceIls and a layer of expanded cells.

The secondary phloem of Austrobaileya scandens

1970 ◽  
Vol 48 (2) ◽  
pp. 341-359 ◽  
Author(s):  
Lalit M. Srivastava
Keyword(s):  
Tannic Acid ◽  
Cross Sections ◽  
Significant Proportion ◽  
Sieve Tube ◽  
Secondary Phloem ◽  
Sieve Elements ◽  
Sieve Cells ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Definition Of

The origin of sieve elements and parenchyma cells in the secondary phloem of Austrobaileya was studied by use of serial cross sections stained with tannic acid – ferric chloride and lacmoid. In three important respects, Austrobaileya phloem recalls gymnospermous features: it has sieve cells rather than sieve-tube members; a significant proportion of sieve elements and companion cells arise independently of each other; and sieve areas occur between sieve elements and companion cells ontogenetically unrelated to each other. The angiospermous feature includes origin of most sieve elements and parenchyma, including companion cells, after divisions in phloic initials. In these instances companion cells show a closer ontogenetic relationship to sieve elements than do other parenchyma cells. The combination of gymnospermous and angiospermous features makes phloem of Austrobaileya unique when compared to that of all those species that have been investigated in detail. It is further suggested that the term albuminous cells is inappropriate and should be replaced by companion cells but that the ontogenetic relationship implicit in the definition of companion cells is too restrictive and should be abandoned.

De l'utilisation du lanthane comme traceur de la voie apoplastique chez Cystoseira nodicaulis (Fucales, Cystoseiraceae)

1991 ◽  
Vol 69 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Liliane Pellegrini ◽  
Marie Epiard-Lahaye ◽  
Michel Penot
Keyword(s):  
Cell Walls ◽  
Long Distance ◽  
Long Distance Transport ◽  
Dense Deposits ◽  
Symplasmic Transport ◽  
Apoplastic Pathway ◽  
Distance Transport ◽  
Kinetics Of ◽  
Dense Marker ◽  
Over Time

Lanthanum was used as an electron-dense marker of apoplastic transport in the brown alga Cystoseira nodicaulis. A lanthanum salt, La(NO3)3, was given in seawater at the base of excised branches for 2–8 days. Lanthanum transport into two regions distant from the point of application, the base and apex of the branches, was followed over time by electron microscopy. Restricted localisation of the deposits confirmed that an apoplastic pathway exists in this alga. The kinetics of transport are slow. Dense deposits were located exclusively in the cell walls of meristoderm and cortex cells. The significance of apoplastic transport in algae is discussed in the context of long-distance transport. The existence of an apoplastic route does not exclude the occurrence of symplasmic transport, which is suggested by the numerous plasmodesmata present in the medulla. Key words: algae, apoplast, Cystoseira, lanthanum, long-distance transport.

scholarly journals Spatial pattern of long-distance symplasmic transport and communication in trees

2013 ◽  
Vol 8 (11) ◽  
pp. e26191 ◽  
Author(s):  
Katarzyna Sokołowska ◽  
Alicja Maria Brysz ◽  
Beata Zagórska-Marek
Keyword(s):  
Spatial Pattern ◽  
Long Distance ◽  
Symplasmic Transport

Preliminary histological investigations of the defense reactions of three pines to Ceratocystisclavigera and two chemical elicitors

1988 ◽  
Vol 18 (10) ◽  
pp. 1243-1247 ◽  
Author(s):  
François Lieutier ◽  
Alan A. Berryman
Keyword(s):  
Proteinase Inhibitor ◽  
Growth Rings ◽  
Sieve Cells ◽  
Cupric Acetate ◽  
Defense Reactions ◽  
Parenchyma Cells ◽  
Pine Trees ◽  
Potential Mode ◽  
Buffer Control ◽  
Chitosan Resin

The histology of defense reactions in individual pine trees belonging to three species, Pinusponderosa, P. contorta, and P. monticola, to inoculation with Ceratocystisclavigera and injection with chitosan and a proteinase inhibitor inducing factor was investigated after resin fixation with cupric acetate. The synthesis of secondary resins was directly associated with parenchyma cells in the phloem and in the rays of both phloem and sapwood. However, these resins were largely located in the lumen of sieve cells and tracheids. In the case of the fungus and chitosan, resin soaking began in the outer phloem and latewood of the last growth rings, then spread into the inner phloem and earlywood. With the proteinase inhibitor inducing factor, resinosis was similar to that of the buffer control, being much less extensive than with the fungus or chitosan, and occurring mainly in the inner phloem and earlywood. In P. monticola, the reaction was complicated by the appearance of fissures in the phloem, probably caused by tension from resin pressure. Phloem resinosis was accompanied by apparent secretion of phenolic compounds, presumably from parenchyma cells. The possible origin of these secondary resins and the potential mode of action of the chemicals used are discussed.

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.

The fine structure of corn phloem

1972 ◽  
Vol 50 (4) ◽  
pp. 839-846 ◽  
Author(s):  
A. P. Singh ◽  
L. M. Srivastava
Keyword(s):  
Fine Structure ◽  
Long Distance ◽  
Sieve Elements ◽  
Long Distance Transport ◽  
P Protein ◽  
Companion Cells ◽  
Parenchyma Cells ◽  
Vascular Parenchyma ◽  
Predominant Orientation ◽  
Distance Transport

The differentiation of sieve elements, companion cells, and vascular parenchyma in leaf bundles of corn is described. The sieve elements have plastids with distinctive crystalline inclusions, lack P-protein, and have nacreous walls in which the predominant orientation of microfibrils seems to be at right angles to the length of the cell. The companion and vascular parenchyma cells have numerous, well-developed mitochondria. These and other results are discussed in relation to long distance transport in the sieve elements.

scholarly journals Scots pine trees react to drought by increasing xylem and phloem conductivities

2020 ◽  
Vol 40 (6) ◽  
pp. 774-781 ◽  
Author(s):  
Natasa Kiorapostolou ◽  
J Julio Camarero ◽  
Marco Carrer ◽  
Frank Sterck ◽  
Brigita Brigita ◽  
...  
Keyword(s):  
Scots Pine ◽  
Resource Availability ◽  
Annual Ring ◽  
Soil Water Potential ◽  
Long Distance ◽  
Cascading Effects ◽  
Long Distance Transport ◽  
Sieve Cells ◽  
Pine Trees ◽  
Distance Transport

Abstract Drought limits the long-distance transport of water in the xylem due to the reduced leaf-to-soil water potential difference and possible embolism-related losses of conductance and of sugars in the phloem due to the higher viscosity of the dehydrated sugary solution. This condition can have cascading effects in water and carbon (C) fluxes that may ultimately cause tree death. We hypothesize that the maintenance of xylem and phloem conductances is fundamental for survival also under reduced resource availability, when trees may produce effective and low C cost anatomical adjustments in the xylem and phloem close to the treetop where most of the hydraulic resistance is concentrated. We analyzed the treetop xylem and phloem anatomical characteristics in coexisting Scots pine trees, symptomatic and non-symptomatic of drought-induced dieback. We selected the topmost 55 cm of the main stem and selected several sampling positions at different distances from the stem apex to test for differences in the axial patterns between the two groups of trees. We measured the annual ring area, the tracheid hydraulic diameter (Dh) and cell wall thickness (CWT), the conductive phloem area and the average lumen diameter of the 20 largest phloem sieve cells (Dph). Declining trees grew less than the non-declining ones, and despite the similar axial scaling of anatomical traits, had larger Dh and lower CWT. Moreover, declining trees had wider Dph. Our results demonstrate that even under drought stress, maintenance of xylem and phloem efficiencies is of primary importance for survival, even if producing fewer larger tracheids may lead to a xylem more vulnerable to embolism formation.

Translocation in Saccorhiza dermatodea (Laminariales, Phaeophyceae): anatomy and physiology

1982 ◽  
Vol 60 (10) ◽  
pp. 2164-2184 ◽  
Author(s):  
C. J. Emerson ◽  
R. G. Buggeln ◽  
A. K. Bal
Keyword(s):  
Freeze Substitution ◽  
Long Distance ◽  
Anatomy And Physiology ◽  
Sieve Cells ◽  
Secondary Wall Deposition ◽  
Translocation Velocity ◽  
Sieve Plates ◽  
Glycine Content ◽  
Intercellular Connections

An anatomical, ultrastructural, histoautoradiographic, and physiological study was made of the kelp Saccorhiza dermatodea, which possesses an anatomy "atypical" of Laminariales. A freeze-substitution – histoautoradiographic procedure localized 14C-labelled organic matter in highly elongated cells (solenocysts) in the medulla of Saccorhiza. These cells are the major long-distance, symplastic translocation pathway in this alga. Solenocysts are joined to each other via numerous lateral connections involving small intermediary cells called allelocysts. Sieve plates (pore diam: ca. 0.05 μm; pore density: ca. 100 μm−2), pierced by plasmodesmata in which an occasional tubule may be seen, are present at all allelocyst–solenocyst junctions as well as at intercellular connections in the cortex and meristodermal layers. Solenocyst ultrastructure closely resembles that of typical sieve cells of Laminariales. Secondary wall deposition occurs between June and October constricting the numerous lateral sieve plates and nearly occluding the cell lumen; however, no callose plugging was observed in any of the medullary cells. In vivo14C-photoassimilate transport was monitored in S. dermatodea blades using a Geiger–Müller probe. The translocation velocity was estimated at 60–100 mm∙h−1 with a greater translocation rate during the day than at night. Amino acid analyses of the S. dermatodea exudate showed a high alanine and glycine content with maximum concentrations 300 mm above the blade base. Nearly 90% of the 14C activity in both source and sink portions of the blade was in alcohol-soluble matter at the end of 72-h experiments. The unique anatomy of the Saccorhiza blade lends it to experimental exploration of the translocation process in kelp.

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