scholarly journals Plastids features and transfer cells occurrence in the phloem of Portulaca mucronata and P. hirsutissima (Portulacaceae)

2014 ◽  
Vol 64 (2) ◽  
pp. 149-153 ◽  
Author(s):  
Maria E. Maranhão Estelita ◽  
Tereza C. Marinho
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Transfer Cells ◽  
Leaf Structure ◽  
Primary Cell Wall ◽  
Starch Grains ◽  
Kranz Anatomy ◽  
Phloem Parenchyma ◽  
Serra Do Cipó ◽  
Parenchyma Cells

The species of the <em>Portulacaceae</em> of the Serra do Cipó, State of Minas Gerais, Brasil, were studied. In <em>Portulaca mucronata</em> and <em>P. hirsutissima</em> transfer cells are companion and phloem parenchyma cells; they have the same secondary cell wall features, that is, short papillate protuberances which are uniformly distributed around the primary cell wall. These features are similar in both species but they are very distinct from others referred in the literature; this could be useful in Taxonomy. The phloem plastids have a globular protein crystalloid, surrounded by proteinaceous filaments. In <em>P. hirsutissima</em> few starch grains may also be present, and this occurrence is considered primitive in the phylogenetic scale. These features agree with presumptive evolution of those of leaf structure: <em>P. hirsutissima</em> has C<sub>3</sub> photosynthesis structure, and <em>P. mucronata</em> C<sub>4</sub> or Kranz anatomy.

scholarly journals The Cell Wall Structure of Xylem Parenchyma

1952 ◽  
Vol 5 (2) ◽  
pp. 223 ◽  
Author(s):  
AB Wardrop ◽  
HE Dadswell
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Secondary Cell Wall ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Xylem Parenchyma ◽  
Cell Axis ◽  
X Ray ◽  
Ray Methods ◽  
Longitudinal Cell

The fine structure of the cell wall of both ray and vertical parenchyma has been investigated. In all species examined secondary thickening had occurred. In the primary cell wall the micellar orientation was approximately trans"erse to the longitudiJ)aI cell axis. Using optical and X-ray methods the secondary cell wall was shown to possess a helical micellar organization, the micelles being inclined between 30� and 60� to the longitudinal cell axis.

scholarly journals Unraveling the puzzle of phloem parenchyma transfer cell wall ingrowth

2020 ◽  
Vol 71 (16) ◽  
pp. 4617-4620 ◽  
Author(s):  
Tyler J McCubbin ◽  
David M Braun
Keyword(s):  
Cell Wall ◽  
Phloem Loading ◽  
Transfer Cells ◽  
Transfer Cell ◽  
Phloem Parenchyma ◽  
Wall Ingrowth ◽  
Experimental Botany

This article comments on: Wei X, Nguyen ST, Collings DA, McCurdy DW. 2020. Sucrose regulates wall ingrowth deposition in phloem parenchyma transfer cells in Arabidopsis via affecting phloem loading activity. Journal of Experimental Botany 71, 4690–4702.

scholarly journals The Placenta of Physcomitrium patens: Transfer Cell Wall Polymers Compared across the Three Bryophyte Groups

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 378
Author(s):  
Jason S. Henry ◽  
Karen S. Renzaglia
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Transfer Cells ◽  
Primary Cell ◽  
Transfer Cell ◽  
Primary Cell Wall ◽  
Slight Variation ◽  
Wall Ingrowths ◽  
Cell Wall Polymers

Following similar studies of cell wall constituents in the placenta of Phaeoceros and Marchantia, we conducted immunogold labeling TEM studies of Physcomitrium patens to determine the composition of cell wall polymers in transfer cells on both sides of the placenta. Sixteen monoclonal antibodies were used to localize cell wall epitopes in the basal walls and wall ingrowths in this moss. In general, placental transfer cell walls of P. patens contained fewer pectins and far fewer arabinogalactan proteins AGPs than those of the hornwort and liverwort. P. patens also lacked the differential labeling that is pronounced between generations in the other bryophytes. In contrast, transfer cell walls on either side of the placenta of P. patens were relatively similar in composition, with slight variation in homogalacturonan HG pectins. Compositional similarities between wall ingrowths and primary cell walls in P. patens suggest that wall ingrowths may simply be extensions of the primary cell wall. Considerable variability in occurrence, abundance, and types of polymers among the three bryophytes and between the two generations suggested that similarity in function and morphology of cell walls does not require a common cell wall composition. We propose that the specific developmental and life history traits of these plants may provide even more important clues in understanding the basis for these differences. This study significantly builds on our knowledge of cell wall composition in bryophytes in general and in transfer cells across plants.

scholarly journals Golgi-localized GALT7 and GALT8 participate in cellulose biosynthesis

2021 ◽  
Author(s):  
Pieter Nibbering ◽  
Romain Castilleux ◽  
Gunnar Wingsle ◽  
Totte Niittylä
Keyword(s):  
Cell Wall ◽  
Golgi Apparatus ◽  
Secondary Cell Wall ◽  
Plant Cell Wall ◽  
Arabinogalactan Protein ◽  
Primary Cell Wall ◽  
Cellulose Content ◽  
Cellulose Biosynthesis ◽  
Cell Wall Assembly ◽  
Protein Levels

AbstractArabinogalactan protein (AGP) glycan biosynthesis in the Golgi apparatus contributes to plant cell wall assembly, but the mechanisms underlying this process are largely unknown. Here, we show that two putative galactosyltransferases -named GALT7 and GALT8 -from the glycosyltransferase family 31 (GT31) of Arabidopsis thaliana participate in cellulose biosynthesis. galt7galt8 mutants show primary cell wall defects manifesting as impaired growth and cell expansion in seedlings and etiolated hypocotyls, along with secondary cell wall defects, apparent as collapsed xylem vessels and reduced xylem wall thickness in the inflorescence stem. These phenotypes were associated with a ∼30% reduction in cellulose content, a ∼50% reduction in secondary cell wall CELLULOSE SYNTHASE (CESA) protein levels and reduced cellulose biosynthesis rate. CESA transcript levels were not significantly altered in galt7galt8 mutants, suggesting that the reduction in CESA levels was caused by a post-transcriptional mechanism. We provide evidence that both GALT7 and GALT8 localise to the Golgi apparatus, while quantitative proteomics experiments revealed reduced levels of the entire FLA subgroup B in the galt7galt8 mutants. This leads us to hypothesize that a defect in FLA subgroup B glycan biosynthesis reduces cellulose biosynthesis rate in galt7galt8 mutants.

Complete substitution of a secondary cell wall with a primary cell wall in Arabidopsis

Nature Plants ◽  
2018 ◽  
Vol 4 (10) ◽  
pp. 777-783 ◽  
Author(s):  
Shingo Sakamoto ◽  
Marc Somssich ◽  
Miyuki T. Nakata ◽  
Faride Unda ◽  
Kimie Atsuzawa ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
Primary Cell ◽  
Primary Cell Wall

scholarly journals Molecular Changes Concomitant with Vascular System Development in Mature Galls Induced by Root-Knot Nematodes in the Model Tree Host Populus tremula × P. alba

2020 ◽  
Vol 21 (2) ◽  
pp. 406 ◽  
Author(s):  
Fabien Baldacci-Cresp ◽  
Marc Behr ◽  
Annegret Kohler ◽  
Nelly Badalato ◽  
Kris Morreel ◽  
...  
Keyword(s):  
Cell Wall ◽  
Secondary Cell Wall ◽  
De Novo ◽  
Vascular System ◽  
System Development ◽  
Primary Cell Wall ◽  
Root Knot Nematode ◽  
Vascular Differentiation ◽  
Vascular Tissues ◽  
Model Tree

One of the most striking features occurring in the root-knot nematode Meloidogyne incognita induced galls is the reorganization of the vascular tissues. During the interaction of the model tree species Populus and M. incognita, a pronounced xylem proliferation was previously described in mature galls. To better characterise changes in expression of genes possibly involved in the induction and the formation of the de novo developed vascular tissues occurring in poplar galls, a comparative transcript profiling of 21-day-old galls versus uninfected root of poplar was performed. Genes coding for transcription factors associated with procambium maintenance and vascular differentiation were shown to be differentially regulated, together with genes partaking in phytohormones biosynthesis and signalling. Specific signatures of transcripts associated to primary cell wall biosynthesis and remodelling, as well as secondary cell wall formation (cellulose, xylan and lignin) were revealed in the galls. Ultimately, we show that molecules derived from the monolignol and salicylic acid pathways and related to secondary cell wall deposition accumulate in mature galls.

scholarly journals The origin and early evolution of tracheids in vascular plants: integration of palaeobotanical and neobotanical data

2000 ◽  
Vol 355 (1398) ◽  
pp. 857-868 ◽  
Author(s):  
William E. Friedman ◽  
Martha E. Cook
Keyword(s):  
Cell Wall ◽  
Vascular Plants ◽  
Secondary Cell Wall ◽  
Early Evolution ◽  
Land Plants ◽  
Primary Cell Wall ◽  
Wall Structure ◽  
Cell Wall Formation ◽  
Wall Formation ◽  
Resistant Layer

Although there is clear evidence for the establishment of terrestrial plant life by the end of the Ordovician, the fossil record indicates that land plants remained extremely small and structurally simple until the Late Silurian. Among the events associated with this first major radiation of land plants is the evolution of tracheids, complex water–conducting cells defined by the presence of lignified secondary cell wall thickenings. Recent palaeobotanical analyses indicate that Early Devonian tracheids appear to possess secondary cell wall thickenings composed of two distinct layers: a degradation–prone layer adjacent to the primary cell wall and a degradation–resistant (possibly lignified) layer next to the cell lumen. In order to understand better the early evolution of tracheids, developmental and comparative studies of key basal (and potentially plesiomorphic) extant vascular plants have been initiated. Ultra–structural analysis and enzyme degradation studies of wall structure (to approximate diagenetic alterations of fossil tracheid structure) have been conducted on basal members of each of the two major clades of extant vascular plants: Huperzia (Lycophytina) and Equisetum (Euphyllophytina). This research demonstrates that secondary cell walls of extant basal vascular plants include a degradation–prone layer (‘template layer’) and a degradation–resistant layer (‘resistant layer’). This pattern of secondary cell wall formation in the water–conducting cells of extant vascular plants matches the pattern of wall thickenings in the tracheids of early fossil vascular plants and provides a key evolutionary link between tracheids of living vascular plants and those of their earliest fossil ancestors. Further studies of tracheid development and structure among basal extant vascular plants will lead to a more precise reconstruction of the early evolution of water–conducting tissues in land plants, and will add to the current limited knowledge of spatial, temporal and cytochemical aspects of cell wall formation in tracheary elements of vascular plants.

Cytochemistry of defense responses in cassava infected by Xanthomonas campestris pv. manihotis

1996 ◽  
Vol 42 (11) ◽  
pp. 1131-1143 ◽  
Author(s):  
K. Kpémoua ◽  
B. Boher ◽  
M. Nicole ◽  
P. Calatayud ◽  
J. P. Geiger
Keyword(s):  
Cell Wall ◽  
Bacterial Growth ◽  
Xanthomonas Campestris ◽  
Secondary Cell Wall ◽  
Defense Responses ◽  
Resistant Variety ◽  
Xylem Parenchyma ◽  
Callose Deposition ◽  
Wide Range ◽  
Parenchyma Cells

Stems of susceptible and resistant cassava plants have been cytologically investigated for their defense reactions to an aggressive strain of Xanthomonas campestris pv. manihotis. Histochemistry, in conjunction with gold cytochemistry, revealed that in susceptible and resistant plants, phloem and xylem parenchyma cells displayed a wide range of responses that limited the bacterial growth within the infected plants. Lignification and suberization associated with callose deposition were effective mechanisms that reinforced host barriers in the phloem. In the infected xylem, vessels were plugged by a material of pectic and (or) lignin-like origin. Flavonoids have been seen to be incorporated in secondary cell wall coatings. These reactions occurred at a higher intensity in the resistant plants. The number of phoem and xylem cells producing autofluorescent compounds was higher in infected resistant plants than in susceptible plants. Reactions have been observed in the resistant variety only, such as secretion of phenol-like molecules by tyloses and hyperplasic activity of phloem cells that compartmentalized bacterial lysis pockets, which are potent secondary inoculum sources.Key words: lignin, suberin, callose, phenol, tylose, flavonoid, pectin.

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