Formation of tyloses in felled Quercus rubra L.

Murmanis, Lidija

doi:10.1007/bf00351911

Cited by 46 publications

(35 citation statements)

References 10 publications

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“…Contrary to a previous study indicating that the walls of tyloses in Q. rubra were only of a primary nature (Murmanis 1975), another investigation indicated that the ultrastructure of the different wall layers in tyloses of Q. rubra resembled the compound middle lamella and secondary wall of normal xylem elements (Sachs et al 1970). This latter structural organization is similar to the one described for mature tyloses in Eucalyptus obliqua (Foster 1967).…”

Section: Discussioncontrasting

confidence: 39%

“…For the industry, it has been frequently reported that the occurrence of tyloses renders treatment of the wood (for preservation, for instance) more difficult (Gerry 1914;Koran and C6t~ 1965;Meyer 1967;Murmanis 1975;Panshin and de Zeeuw 1980;Obst et al 1988). There is no doubt that the presence of suberin, as suggested by others (Parameswaran et al 1985), and of higher concentrations of lignin in the tylosis wall will cause more problems during wood impregnation.…”

Section: Discussionmentioning

confidence: 99%

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Suberized tyloses in trees: An ultrastructural and cytochemical study

Rioux

Chamberland

Simard

et al. 1995

Planta

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The nature of the wall layers observed in suberized tyloses was studied in Populus basalmifera L., Ulmus americana L. and Quercus rubra L. As the suberin layers were present only in tyloses that had completed their expansion, most of the results concern mature tyloses. The cyto-and immunocytochemical tests were conducted, respectively, with an exoglucanase having a binding affinity for 13(l~4)-D-glucans, the subunits of cellulose, and with two monoclonal antibodies specific for un-esterified and esterified pectic molecules. In the three species, labelling for pectic compounds was intense over the external layer of tyloses but usually more dispersed or nearly absent over the layer corresponding to a primary wall that was, however, intensely labelled for 13(1 ~4)-Dglucans. The outer wall layer, comparable to a middle lamella in mature tyloses, was continuous with similar material that appeared to be secreted by the tylosis. This material was particularly abundant in pit chambers, in void spaces between the tylosis and the vessel wall, particularly at the junction of the vessel and two adjacent cells, and close to the rim of vessel perforation plates. In P. balsamifera, a single suberized layer or occasionally a succession of suberized and cellulose-containing layers was observed internal to the tylosis primary wall. In U. americana, the wall of tylosis was similar to that of P. balsamifera except that, at times, a secondary-wall-like layer was formed and only a single suberized layer was observed. In Q. rubra, the suberized layer was always observed internal to the tylosis secondary wall. Simple pits were also constantly noted in Q. rubra tyloses. The occasional occurrence of a cellulosic layer internally to the suberized layer was observed in the three species. Histochemical tests revealed that lignin was also an important component of the tylosis wall. The tyloses frequently contained phenolic compounds in close association with the suberized layers. The significance of the formation of suberized tyloses in trees is discussed.Abbreviation: TEM = transmission electron microscope

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Section: Discussioncontrasting

confidence: 39%

Section: Discussionmentioning

confidence: 99%

Suberized tyloses in trees: An ultrastructural and cytochemical study

Rioux

Chamberland

Simard

et al. 1995

Planta

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“…the ®rst hours or days) may determine the ability of the tree to restrict the long-term spread of decay resulting from infection [1, 14, 23±25]. Increased oxygen access following wounding has been linked to the production of antimicrobial phenolics [8,29] while changes in vessel osmotic potential can lead to the formation of tyloses [20]. The formation of tyloses and phenolics as defence responses appear ubiquitous among woody plants [23,37].…”

Section: Introductionmentioning

confidence: 99%

Initial defence responses in sapwood of Eucalyptus nitens(Maiden) following wounding and fungal inoculation

Barry

Pearce

Evans

et al. 2001

Physiological and Molecular Plant Pathology

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Xylem defence responses occurring in pot-grown Eucalyptus nitens (Maiden) saplings were analysed within the ®rst few weeks following stem wounding and inoculation with the non-aggressive decay fungus Ganoderma adspersum (Schulz). The fungus colonized the dead xylem cells up to 5 mm above and below the wound after 30 days. Evidence of xylem cell death and discolouration was detectable within 12 h and vessel tyloses were present after 3 days. Concentration of tetra-galloylglucose increased by 3 . 5-fold within 24 h, while the trend for total phenols was a slow increase reaching a maximum after 21 days. Suberin was not detected. Early accumulation of water content has been proposed as a defence component of host± pathogen interactions in woody angiosperm xylem, but this was not obvious for E. nitens. Nuclear magnetic resonance imaging (NMR imaging or MRI) was used to measure small-scale distributions in moisture content around the inoculated stem wounds in intact E. nitens saplings. Some moisture accumulation was detectable at lesion margins of wounds analysed after 3 weeks. However, this was not detectable by gravimetric measurements. This increase in moisture content may be a consequence of wound physiology rather than an active defence response.*

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“…Since this first report, similar structures have been observed in many other species. Several authors have provided evidence for its role in the formation of tyloses (Foster 1967;Murmanis 1975), freezing avoidance of the xylem (Wisniewski and Davis 1989), strengthening of the pit membrane, or facilitating intercellular transport (Van Bel and Van der Schoot 1988). All of these hypotheses, however, have been contradicted by other studies (Wooding and Northcote 1965;Chafe 1974;Wisniewski et al 1987;Van Bel and Van der Schoot 1988;Wisniewski and Davis 1989;Barnett et al 1993).…”

Section: Plasmodesmata In Pit Membranes and Function Of Pseudo-torimentioning

confidence: 99%

A comparative ultrastructural study of pit membranes with plasmodesmata associated thickenings in four angiosperm species

Rabaey¹,

Lens²,

Huysmans³

et al. 2008

Protoplasma

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Recent micromorphological observations of angiosperm pit membranes have extended the number and range of taxa with pseudo-tori in tracheary elements. This study investigates at ultrastructural level (TEM) the development of pseudo-tori in the unrelated Malus yunnanensis, Ligustrum vulgare, Pittosporum tenuifolium, and Vaccinium myrtillus in order to determine whether these plasmodesmata associated thickenings have a similar developmental pattern across flowering plants. At early ontogenetic stages, the formation of a primary thickening was observed, resulting from swelling of the pit membrane in fibre-tracheids and vessel elements. Since plasmodesmata appear to be frequently, but not always, associated with these primary pit membrane thickenings, it remains unclear which ultrastructural characteristics control the formation of pseudo-tori. At a very late stage during xylem differentiation, a secondary thickening is deposited on the primary pit membrane thickening. Plasmodesmata are always associated with pseudo-tori at these final developmental stages. After autolysis, the secondary thickening becomes electron-dense and persistent, while the primary thickening turns transparent and partially or entirely dissolves. The developmental patterns observed in the species studied are similar and agree with former ontogenetic studies in Rosaceae, suggesting that pseudo-tori might be homologous features across angiosperms.

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Formation of tyloses in felled Quercus rubra L.

Cited by 46 publications

References 10 publications

Suberized tyloses in trees: An ultrastructural and cytochemical study

Suberized tyloses in trees: An ultrastructural and cytochemical study

Initial defence responses in sapwood of Eucalyptus nitens(Maiden) following wounding and fungal inoculation

A comparative ultrastructural study of pit membranes with plasmodesmata associated thickenings in four angiosperm species

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