Internal Phloem Development in Pharbitis nil Chois. (Convolvulaceae)

Mikesell, Jan E.; Schroeder, Allen C.

doi:10.1086/337446

Cited by 12 publications

(9 citation statements)

References 7 publications

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“…Similar observations are also reported in Irish potato by Artschwager (1918), in Quisqualis indica by Baranetzky (1900) and in Combretum rotundifolium by Zozimo et al (2011). In contrast, Mikesell and Schroeder (1984) documented its origin after the differentiation of external phloem in Pharbitis nil of the Convolvulaceae.…”

Section: Discussionsupporting

confidence: 80%

“…There is a controversy about the origin of internal phloem. According to earlier researchers, it may develop from various tissues such as: i) procambium (Scott & Brebner 1889;Baranetzky 1900;Kennedy & Crafts 1931;Zozimo et al 2011), ii) procambial derivatives (Fukuda 1967;Mikesell & Schroeder 1984;Patil et al 2009), or iii) dedifferentiation of the marginal pith cells (Esau 1938;Singh 1943;Patil & Rajput 2008;Patil et al 2009). In the present study internal protophloem originates from procambial derivatives while secondary internal phloem develops from an internal cambium.…”

Section: Discussionsupporting

confidence: 52%

“…However, internal phloem is usually separated from protoxylem by a few parenchyma cell layers (Fukuda 1967). Ontogenetically, internal phloem is regarded as primary in origin (Worsdell 1915;Artschwager 1918;Kennedy & Crafts 1931;Woodcock 1935;Esau 1938;Fukuda 1967, Mikesell & Schroeder 1984. It arises at the inner margin of the procambial ring by irregular longitudinal divisions in cells situated on the inner side of the procambium and differentiates centrifugally into phloem elements (Baranetzky 1900;Esau 1938).…”

Section: Discussionmentioning

confidence: 99%

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Structure And Development Of Internal Phloem In Solanum Pseudocapsicum (Solanaceae)

Patil¹,

Koyani²,

Sanghvi³

et al. 2014

IAWA J

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The development of internal phloem in the Jerusalem cherry, Solanum pseudocapsicum L. (Solanaceae), was studied in young and mature stems. The early presence of primary internal phloem is succeeded by the development of secondary internal phloem from an internal cambium situated between the protoxylem and primary internal phloem. In the second and third visible internodes of the young stem, procambial derivatives begin to differentiate as discrete strands of internal protophloem in a perimedullary position prior to the differentiation of protoxylem and external protophloem. In 6–8 mm diameter stems, sieve elements of the internal phloem become non-conducting, begin to collapse, and undergo obliteration. In 15–20 mm diameter stems internal cambium is initiated from the parenchyma cells situated between the protoxylem and primary internal phloem. The development of internal phloem and an internal cambium in S. pseudocapsicum is compared with that in other taxa. There seems to be a gradual variation in the origin of an internal cambium from either remnants of the procambium or dedifferentiation of peripheral pith cells across dicotyledons with an internal cambium.

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Section: Discussionsupporting

confidence: 80%

Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 99%

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Structure And Development Of Internal Phloem In Solanum Pseudocapsicum (Solanaceae)

Patil¹,

Koyani²,

Sanghvi³

et al. 2014

IAWA J

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“…Based on the summaries in Metcalfe & Chalk (1950), it is interesting to note that cambial conversion of the inner portion of bicollateral bundles into medullary bundles is not known in Cucurbitaceae and Myrtales, but does occur in some members of Apocynaceae, Asclepiadaceae, Convolvulaceae, Gentianaceae, Loganiaceae (Buddleioideae excluded), Solanaceae, and one non-asterid family, Polygonaceae. Among these families, anomalous xylem production resulting in the formation of inverted medullary bundles has been reported sporadically, including the following (Metcalfe & Chalk 1950;and others, as cited): Apocynum (Holm 1910) and Willughbeia (Apocynaceae); Leptadenia (Asclepiadaceae) (Singh 1943); many genera of Convolvulaceae (Mikesell & Schroeder 1984;Carlquist & Hanson 1991); Gelsemium (Loganiaceae); Gentiana (Gentianaceae); Rumex (Polygonaceae) (Joshi 1936;Maheshwari 1929;Maheshwari & Singh 1942); and also Campsis (Bignoniaceae) (Handa 1936). The case of Gentiana is notable in that external phloem is described as weakly developed, much as was found in Croton glandulosus var.…”

Section: Internal Phloem and Medullary Bundlesmentioning

confidence: 99%

Stem Development, Medullary Bundles, and Wood Anatomy of Croton Glandulosus Var. Septentrionalis (Euphorbiaceae)

Hayden¹,

Hayden²

1994

IAWA J

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Anatomy and development of vascular tissues in the annual stems of Croton glandulosus var. septentrionalis are described. In primary stages of growth the stem possesses a eustele of bicollateral bundles; internal phloem is notably more extensive than the external. In addition to a vascular cambium and secondary xylem that form in the usual fashion, additional cambia add cells to the internal phloem portion of the bicollateral bundles, forming well-marked medullary bundles at the perimeter of the pith. At first, the perimedullary cambial strands produce only internal secondary phloem; later, internal secondary xylem is also formed in some stems. When internal secondary xylem is present, the medullary bundles have an inverted orientation, i.e., phloem innermost (towards centre of pith) and xylem outermost (near protoxylem). Cells of the medullary bundles include sieve tube elements, vessel ekments, and fibres. Normal (external) secondary phloem is weakly developed. Normal secondary xylem contains short vessel elements with simple perforation plates and alternate intervascular pits, libriform fibres, narrow heterocellular rays, and lacks axial parenchyma.

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“…4-8, 12), the effect of in-version was greatest in pith cells (65% over that of controls), in tracheary elements (52%), and phloem cells (internal phloem, 50%; external phloem, 27%). The distribution of the phloem in the stem of Pharbitis nil has been described by Mikesell and Schroeder (1984). In pith cells and in tracheary elements, the increase was especially dramatic during the second day oftreatment.…”

mentioning

confidence: 99%

Effects of Shoot Inversion on Stem Structure in Pharbitis Nil

Prasad

Sack²,

Cline³

1988

American J of Botany

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The effects of shoot inversion on stem structure over 72 hr were investigated in Pharbitis nil by analyzing cell number, cell length, and the cross sectional areas of cells, tissues, and regions. An increase in stem diameter can be attributed to an increase in both cell number and cross sectional area of pith (primarily) and vascular tissue (secondarily). Qualitative observations of cell wall thickness in the light microscope did not reveal any significant effects of shoot inversion on this parameter. The inhibition of shoot elongation was accompanied by a significant decrease in cell length in the pith. The results are generally consistent with an ethylene effect on cell dimensions, especially in the pith.

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Internal Phloem Development in Pharbitis nil Chois. (Convolvulaceae)

Cited by 12 publications

References 7 publications

Structure And Development Of Internal Phloem In Solanum Pseudocapsicum (Solanaceae)

Structure And Development Of Internal Phloem In Solanum Pseudocapsicum (Solanaceae)

Stem Development, Medullary Bundles, and Wood Anatomy of Croton Glandulosus Var. Septentrionalis (Euphorbiaceae)

Effects of Shoot Inversion on Stem Structure in Pharbitis Nil

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