Developmental Changes in the Vascular Cambium in Leitneria Floridana

Cumbie, B. G.

doi:10.1002/j.1537-2197.1967.tb10659.x

Cited by 20 publications

(22 citation statements)

References 23 publications

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“…Asteraceae, notably Senecioneae; Carlquist, 1966), but that is because of intrusive growth of fibres, which therefore do not exhibit the storied pattern of the fusiform cambial initials from which they are derived. Delayed onset of storying ontogenetically is a theoretical instance of heterochrony, but, in fact, rapid onset of the storied condition during secondary growth has been reported instead (Cumbie, 1963, 1967; Davidson, 1976).…”

Section: The Concept and Criteriamentioning

confidence: 99%

Xylem heterochrony: an unappreciated key to angiosperm origin and diversifications

Carlquist

2009

Botanical Journal of the Linnean Society

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All angiosperms can be arranged along a spectrum from a preponderance of juvenile traits (cambial activity lost) to one of nearly all adult characters (cambium maximally active, mature patterns realized rapidly early in ontogeny). Angiosperms are unique among seed plants in the width of this spectrum. Xylem patterns are considered here to be indicative of contemporary function, not relictual. Nevertheless, most families of early-divergent angiosperms exhibit paedomorphic xylem structure, a circumstance that is most plausibly explained by the concept that early angiosperms had sympodial growth forms featuring limited accumulation of secondary xylem. Sympodial habits have been retained in various ways not only in early-divergent angiosperms, but also among eudicots in Ranunculales. The early angiosperm vessel, relatively marginal in conductive abilities, was improved in various ways, with concurrent redesign of parenchyma and fibre systems to enhance conductive, storage and mechanical capabilities. Flexibility in degree of cambial activity and kinds of juvenile/adult expressions has been basic to diversification in eudicots as a whole. Sympodial growth that lacks cambium, such as in monocots, provides advantages by various features, such as organographic compartmentalization of tracheid and vessel types. Woody monopodial eudicots were able to diversify as a result of production of new solutions to embolism prevention and conductive efficiency, particularly in vessel design, but also in parenchyma histology. Criteria for paedomorphosis in wood include slow decrease in length of fusiform cambial initials, predominance of procumbent ray cells and lesser degrees of cambial activity. Retention of ancestral features in primary xylem (the 'refugium' effect) is, in effect, a sort of inverse evidence of acceleration of adult patterns in later formed xylem. Xylem heterochrony is analysed not only for all key groups of angiosperms (including monocots), but also for different growth forms, such as lianas, annuals, various types of perennials, rosette trees and stem succulents. Xylary phenomena that potentially could be confused with heterochrony are discussed. Heterochronous xylem features seem at least as important as other often cited factors (pollination biology) because various degrees of paedomorphic xylem are found in so many growth forms that relate in xylary terms to ecological sites. Xylem heterochrony can probably be accessed during evolution by relatively simple gene changes in a wide range of angiosperms and thus represents a current as well as a past source of variation upon which diversification was based. Results discussed here are compatible with both current molecular-based phylogenetic analyses and all recent physiological work on conduction in xylem and thus represent an integration of these fields.

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Section: The Concept and Criteriamentioning

confidence: 99%

Xylem heterochrony: an unappreciated key to angiosperm origin and diversifications

Carlquist

2009

Botanical Journal of the Linnean Society

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“…3). All of the rays are uniseriate 139 I Received for publication 19 April 1968. THE MOST intensive studies on the developmental changes in the vascular cambium associated with the increase in circumference of this meristem have been made on conifers (Bannan, 1950(Bannan, , 1957(Bannan, , 1960bWhalley, 1950;Hejnowicz, 1961) and on some species of arborescent dicotyledons (Evert, 1961;Cheadle and Esau, 19(:\4;Cumbie, 1967). Except for an investigation of a species of Hibiscus (Cumbie, 1963), there have been no intensive studies on the developmental changes in the vascular cambium in the herbaceous dicotyledons.…”

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confidence: 99%

Developmental Changes in the Vascular Cambium of Polygonum Lapathifolium

Cumbie

1969

American J of Botany

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Developmental changes in the vascular cambium of Polygonum lapathifolium were determined primarily by an analysis of the secondary xylem. The cambium and xylem consist of fascicular and interfascicular regions in this herbaceous dicotyledon. Near the pith vessels are restricted to the fascicular regions of the xylem. During secondary growth vessels are formed in some radial files in the interfascicular regions. Anticlinal divisions are of two types, oblique and lateral. In interfascicular files consisting of fibers only, about two‐thirds of the anticlinal divisions are oblique. The oblique partition averages 31% of the length of the dividing initials. In interfascicular files consisting of vessel elements and fibers, there are almost equal numbers of oblique and lateral divisions. The oblique partition averages 37% of the length of the dividing initials in these files. Lateral divisions account for approximately three‐fifths of the anticlinal divisions in the fascicular regions, consisting of vessel elements and fibers. The partitions formed in oblique anticlinal divisions average 64% of the length of the dividing cells in the fascicular regions. The frequency of anticlinal division is much higher in files consisting of vessel elements and fibers than in those consisting of fibers only. There is no loss of fusiform initials, except by ray formation. Ray initiation occurs by simple subdivision of fusiform initials. The findings are discussed in relation to the developmental changes in the vascular cambium in plants of different habits.

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“…Other references to the activity and structure of vascular cambium and its derivatives in both angiosperm and gymnosperm trees have also considered the frequency of anticlinal divisions (Angiosperms – e.g. Evert 1961; Cumbie 1967; Gymnosperms – e.g. Bannan 1957a, 1968; Hejnowicz 1961).…”

Section: Discussionmentioning

confidence: 99%

Estimation of directional division frequencies in vascular cambium and in marginal meristematic cells of plants

2002

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Using simple arithmetical formulae, it is shown that, when the meristematic initial cells of a growing plant organ are arranged in a ring, the cellular dimensions predict the relative frequencies of anticlinal and periclinal divisions which these cells undergo. The pattern of cell file branching which appears during the course of development, and which is predicted by this mathematical model, is validated using data pertaining to the numbers and dimensions of initial cells within the secondary vascular cambium of hybrid aspen trees. Data pertaining to a second, simpler set of initial cells which comprises the outer cellular ring of the thallus of the alga Coleochaete orbicularis, and from which all the radial cell files of the circular disc-like thallus are descended, have also been used for model validation. Combining the mathematical approach to division frequencies with data of actual cell sizes permits inferences about the course of the increase of the number of cell files (generated by the anticlinal divisions) and the number of cells within each file (generated by the periclinal divisions) during the earlier stages of secondary tissue or thallus development, and also about how they will develop at future stages. The question whether or not cell division patterns conform to the geometry of the system in which the cells are embedded is also discussed.

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Developmental Changes in the Vascular Cambium in Leitneria Floridana

Cited by 20 publications

References 23 publications

Xylem heterochrony: an unappreciated key to angiosperm origin and diversifications

Xylem heterochrony: an unappreciated key to angiosperm origin and diversifications

Developmental Changes in the Vascular Cambium of Polygonum Lapathifolium

Estimation of directional division frequencies in vascular cambium and in marginal meristematic cells of plants

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