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Degree

Master of Science, Miami University, Botany, 2012.

Abstract

The ontogeny and phyllotactic transitions of Diphasiastrum digitatum were studied using scanning electron microscopy. Six different types of shoot apical meristem (SAM) and eight different phyllotactic patterns were found. Divergence angle, plastochron ratio, leaf insertion angle, parameter b, parameter Gamma, half conic angle, area, circumference and circularity of the SAM of each pattern of each SAM type were measured and compared. Three discontinuous transitions associated with strobili transformation were found; divergence angle, area, circumference and circularity of the SAM are the important parameters in these transitions. One discontinuous transition associated with fertile shoot and distal strobili was found. Current data matches the direction of change, but not the exact ranges of the Douady and Couder (1996b, 1996c) model. Current data disapproves the Kelly and Cooke (2003) model. Leaf anisophylly is the result of later modification of leaves. Anisotomous dichotomy can result from unequal bifurcation or unequal growth of equal bifurcation.

Subject Headings

Botany; Plant Biology

Keywords

plant development; phyllotaxis; phyllotactic transition; discontinuous transition; ontogeny; Diphasiastrum digitatum; Lycopodiaceae; scanning electron microscopy

Committee / Advisors

Roger Meicenheimer, PhD (Advisor)
James Hickey, PhD (Committee Member)
Richard Moore, PhD (Committee Member)

Document number: miami1356981860
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=miami1356981860

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