Floral Morphology of Arceuthobium americanum

Dowding, Eleanor Silver

doi:10.1086/334124

Cited by 25 publications

(31 citation statements)

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“…Regardless of what the perianth parts are called, there were normally three of them, although there were occasionally four and rarely two. Our data generally concur with those of others (Cohen 1968;Dowding 1931;Sereda 2003), although these authors' results indicated that dimerous flowers occurred more often than we observed. It is difficult to make direct comparisons, however, as those authors did not attempt to quantify the frequency of flower types.…”

Section: Organization Of the Mature Flowersupporting

confidence: 93%

“…Our description of the development of the anther wall layers generally agrees with those provided in other studies of Arceuthobium (Bhandari 1984;Bhandari and Nanda 1968;Cohen 1968;Dowding 1931;Pisek 1924;Thoday and Johnson 1930;Sereda 2003). As in these other studies, we found that the epidermis persisted as a fibrously thickened region (exothecium), an endothecium did not develop, and a primary parietal layer gave rise to a uniseriate tapetum and middle layer.…”

Section: Initiation Of the Anther And Development Of Anther Wall Sposupporting

confidence: 89%

“…Regarding the Arceuthobium anther wall, authors generally agree that the anthers lack a typical fibrously thickened endothecium and instead possess a persistent fibrously thickened epidermis (Bhandari 1984;Bhandari and Nanda 1968;Cohen 1968;Dowding 1931;Sereda 2003). Dowding (1931) used the term "exothecium" to describe this epidermis, whereas Bhandari and Nanda (1968) called it an "epithecium". Largely because the epidermis persists, Cohen (1968), Bhandari (1984), and Sereda (2003) categorized the anther wall type in Arceuthobium as a modified form of the reduced type (Davis 1966).…”

Section: Introductionmentioning

confidence: 99%

“…Sereda (2003) also apparently observed tapetal extensions. As for its organization, various descriptions have suggested that the mature sporangium is ring shaped (Cohen 1968;Dowding 1931;Pisek 1924; Thoday and Johnson 1930), horseshoe shaped (Bhandari and Nanda 1968), or cup shaped (Sereda 2003), and that the sporangium, regardless of shape, encompasses a column of sterile tissue that Thoday and Johnson (1930) as well as Dowding (1931) called the "columella". No author has convincingly demonstrated how this columella develops.…”

Section: Introductionmentioning

confidence: 99%

“…No author has convincingly demonstrated how this columella develops. Both Pisek (1924) and Dowding (1931) suggested that the orientation of the sporangium and columella is highly variable. Further complicating the matter, Bhandari and Vohra (1983) suggested that the horseshoe-shaped sporangium becomes ring shaped at maturity.…”

Section: Introductionmentioning

confidence: 99%

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Anther and pollen development in the lodgepole pine dwarf mistletoe (Arceuthobium americanum) staminate flower

MunroKaitlyn

JacksonJeffrey

Hartling

et al. 2014

Botany

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The lodgepole pine dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm., is a parasitic angiosperm that infects conifers in western Canadian forests. While production of viable pollen in anthers is critical to dwarf mistletoe reproduction, the few existing reports that examine staminate development in Arceuthobium are often incomplete or conflicting. The objective of this work was to investigate the developmental anatomy of anther and pollen of A. americanum using modern microscopy. We found that the microsporangium was toroidal from the outset and gave rise to a central peg-shaped sterile "columella" early in anther development. The endothecium was absent, the epidermis persisted as an "exothecium" fulfilling the role of the endothecium, and a primary parietal layer generated a secretory tapetum and middle layer. Thus, we suggest that a new category of anther wall development, the Arceuthobium type, be created. Microsporogenesis produced tetrahedral microspores via simultaneous cytokinesis and involved callose wall formation. Microgametogenesis resulted in round and atypical generative and vegetative nuclei. Additionally, the heterocolpate, echinate pollen grains, which were shed at the two-celled stage, were seen for the first time in their native state with environmental scanning electron microscopy. This work contributes to the understanding of A. americanum, the genus Arceuthobium, and angiosperms as a whole.Résumé : Le gui nain du pin lodgepole, Arceuthobium americanum Nutt. ex Engelm., est une angiosperme parasite qui infecte les conifères des forêts de l'Ouest du Canada. Alors que la production de pollen viable par les anthères est critique à la reproduction du gui nain, les rapports actuels, peu nombreux, qui se sont penchés sur le développement staminé chez Arceuthobium sont souvent incomplets ou contradictoires. L'objectif de ce travail était d'examiner l'anatomie développementale des anthères et du pollen d'A. americanum par microscopie moderne. Nous avons trouvé que le microsporange était en forme d'anneau dès le début et donnait naissance à une « columelle » centrale conoïde stérile tôt lors du développement de l'anthère. L'endothèque était absente, l'épiderme persistait comme « exothèque », remplissant le rôle de l'endothèque, et une couche pariétale primaire générait un tapetum sécrétoire et une couche intermédiaire; ainsi, nous suggérons qu'une nouvelle modalité de développement de la paroi de l'anthère soit créée, le type « Arceuthobium ». La microsporogenèse produisait des microspores tétraédriques par cytocinèse simultanée, et elle impliquait la formation d'une paroi calleuse. La microgamétogenèse résultait en noyaux génératifs et végétatifs ronds et atypiques. De plus, les grains de pollen hétérocolpés échinés qui étaient libérés au stade biloculaire ont été observés pour la première fois dans leur état natif par microscopie électronique à balayage environnemental. Ce travail contribue à mieux comprendre globalement A. americanum, le genre Arceuthobium, et les angiospermes.

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Section: Organization Of the Mature Flowersupporting

confidence: 93%

Section: Initiation Of the Anther And Development Of Anther Wall Sposupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Anther and pollen development in the lodgepole pine dwarf mistletoe (Arceuthobium americanum) staminate flower

MunroKaitlyn

JacksonJeffrey

Hartling

et al. 2014

Botany

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Anatomy of the Inferior Ovary of Darbya

Smith

1942

American J of Botany

127

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Chromosome Numbers in North American Loranthaceae: (Arceuthobium, Phoradendron, Psittacanthus, Struthanthus)

Wiens

1964

American J of Botany

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Chromosome numbers are reported from 67 populations of 36 taxa, mostly in Phoradendron. The basic number is 14 in Phoradendron and probably also in Arceuthobium. The 4 species of Struthanthus for which chromosome numbers are recorded suggest that the basic number is 8. Numbers of n = 8 and n = 10 have been reported for Psittacanthus. In Phoradendron the 22 taxa examined are all diploid, although 1 instance of polyploidy was discovered. Objects interpreted as supernumerary chromosomes were discovered in a number of species of Phoradendron; no evidence of sex chromosomes previously reported in Phoradendron was observed. The Loranthaceae have chromosomes comparable in size to the largest in the plant kingdom.

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Floral Morphology of Arceuthobium americanum

Cited by 25 publications

References 0 publications

Anther and pollen development in the lodgepole pine dwarf mistletoe (Arceuthobium americanum) staminate flower

Anther and pollen development in the lodgepole pine dwarf mistletoe (Arceuthobium americanum) staminate flower

Anatomy of the Inferior Ovary of Darbya

Chromosome Numbers in North American Loranthaceae: (Arceuthobium, Phoradendron, Psittacanthus, Struthanthus)

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