Date of Award

2013

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Clore, Amy

Keywords

Plant Development, Organ Fusion, ROS Signaling

Area of Concentration

Biology

Abstract

During normal development, the carpels of the Madagascar periwinkle, Catharanthus roseus L. arise as two distinct organs but later make contact and fuse to form a single gynoecium. Significantly, approximately 400 epidermal cells along the site of fusion change their plane of division and eventually redifferentiate into less specialized parenchyma tissue. Understanding the mechanisms by which neighboring cells communicate and orchestrate developmental processes is important to the study of plant development, making this a potentially useful model system. Previously documented increases in carpel cuticle permeability as fusion progresses, together with literature reporting altered cuticle properties in Arabidopsis mutants expressing abnormal organ fusion, suggest that changes in cuticle structure may play a role in C. roseus carpel fusion. Recent research also demonstrates that brassinosteroid signals exchanged between prefusion carpels play an important regulatory role in the fusion process, as inhibiting brassinosteroid biosynthesis results in abnormal, superficial fusion. The present study employed scanning electron microscopy to chart changes in surface structure of both normally fusing carpels and those that were treated with the brassinosteroid biosynthesis inhibitor Brz2001 throughout development. Attempts were also made to further elucidate the carpel fusion signaling pathway through the use of diaminobenzidine tetrahydrochloride (DAB) staining and the inhibition of NADPH-oxidases, two tools commonly used to investigate potential roles of reactive oxygen species. The results suggest that hydrogen peroxide signaling merits future investigation as a likely player in the fusion process. Furthermore, the SEM work generally corroborated earlier studies of gynoecial ontogeny of extracellular structures that may be important in the fusion, and supported the role of brassinosteroids in this fusion.

Rights

This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.

Download

Share

COinS