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Abstract Detail

Anatomy and Morphology


Polystely and Monostely Revisited.

While Van Tieghem and Douliot (1886a, 1886b, 1886c) produced the first major framework for the concept of polystely and monostely in plant stems, De Bary (1877), Schenck (1886) and others had also produced evidence of stems of ferns and flowering plants in which the vascular tissues were enveloped in an endodermis which delimited vascular tissues from fundamental tissues. Then, Jeffrey (1899), Brebner (1902), Arber (1920), Ogura (1972), Beck et al. (1982), Schmid (1983), and others elaborated upon, defined, or utilized the concepts, although most dismissed the importance of the endodermis to the concept. With assistance from others, I have examined many species from more than 35 families whose primary habitat is aquatic or wetland to determine what kinds of barriers can be found between their shoot vascular and fundamental tissues. The vast majority of sampled species has an endodermis with Casparian bands delimiting vascular tissues. Wetland or aquatic ferns always have an endodermis delimiting vascular tissues. In basal angiosperms, Hydellataceae have monosteles, Cabombaceae have polysteles in stolons, and Nymphaeaceae generally have polysteles, while the Sauraceae of the magnoliids have monosteles. Most monocots - from the Acoraceae through Araceae, Hydrocharitaceae, Potamogetonaceae, and Iridaceae to the Typhaceae, Cyperaceae, Poaceae, Pontederiaceae, and Marantaceae - have monosteles, although vascular traces in the cortex are surrounded by endodermis in a few; many species of these families have additional endodermal cell wall structures beyond Casparian bands. Eudicots have much variation from the Ceratophyllaceae with a monostele and Ranuculaceae with or without polysteles to the basal core eudicots, Gunneraceae, which are distinguished by a progression from simple monostele to complex polysteles, where even leaf lamina may have vascular bundles surrounded by endodermis. Other examples with various stelar patterns include members of Haloragaceae, Primulaceae, Lythraceae, Plantaginaceae, Acanthaceae. Lamiaceae, Asteraceae, Menyanthaceae, and Araliaceae; some of these are even characterized by having emergent stems and leaves with endodermis enveloping vascular bundles. In eudicots, endodermis almost always has Casparian bands only.

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1 - Seago Botanical Consulting, Minetto, NY, 13115-0316, USA

Plant Anatomy.

Presentation Type: Oral Paper
Session: 20, Anatomy and Morphology
Location: Fort Worth Ballroom 7/Omni Hotel
Date: Tuesday, June 27th, 2017
Time: 11:30 AM
Number: 20014
Abstract ID:69
Candidate for Awards:None

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