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Abstract Detail



Developmental and Structural Section

Bonacorsi, Nikole [1], Seago, James [2].

Anatomy of Ginkgo biloba with Emphasis on Primary Roots.

We sought to document the development of the primary root of Ginkgo biloba in order to fill in gaps in our knowledge of Ginkgo root structure because there is a paucity of relevant literature concerning the roots of this ancient and well-researched gymnosperm. Using seedlings grown in soil, vermiculite, or a mixture, we examined cross sections at various distances from the root cap to capture a developmental sequence of anatomical structures; we used brightfield, epifluorescence, and confocal microscopy. The development of the vascular cylinder is initiated as either a diarch or triarch stele with widespread protoxylem; this usually develops into a complete disc through the center, except near the transition region where there are batches of tracheary cells. The disc of diarch or triarch xylem soon undergoes secondary growth with many tracheids added within a few weeks. The initial number of protoxylem poles appears to be determined in the embryo, and does not change across development. In the cortex, the endodermis produces Casparian bands early in development and appears to continue into the transition region just below the cotyledons, the petioles of which emerge outside the seed coat. Phi thickenings (lignified walls) of first one layer, even before an evident endodermis, and then a second and even third layer of cortex are evident early in development, and they are present in the entirety of the root once they are observed; they diminish into the transition region. However, phi thickenings do not continue into the cotyledonary region or stem. Cortical ducts are present in the whole of the transition region into the stem. The epidermis of primary roots has root hairs, while lateral roots have prolific root hairs.


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1 - Hamilton College, Department of Biology, 198 College Hill Road, Mailbox 177, Clinton, NY, 13323, USA
2 - SUNY at Oswego, Department of Biological Sciences, NY 104 West, Oswego, NY, 13126, USA

Keywords:
Root Anatomy
Transition region
Ginkgo biloba
Phi-thickenings
Primary xylem
Cortex
Epidermis
Secondary growth.

Presentation Type: Oral Paper:Papers for Sections
Session: 20
Location: Pines North/Boise Centre
Date: Tuesday, July 29th, 2014
Time: 8:30 AM
Number: 20002
Abstract ID:215
Candidate for Awards:None


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