Megagametogenesis and nuclear DNA content estimation in Halophila (Hydrocaritaceae)

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Robert A. York (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Michael Durako

Abstract: Megagametogenesis has been identified in the seagrass Halophila johnsonii, a species with no known seeds, using DAPI staining and manual sectioning methods. Developmental stages were documented and compared with megagametogenesis stages in Halophila decipiens, a related species widely reported to produce viable seeds. Present observations suggest that meiosis occurs in the megasporocyte and, therefore, sexual reproduction should be possible in H. johnsonii. Results of this study, which was part of a multi-level threatened-species recovery plan sponsored by NOAA, are encouraging and suggest that two additional management-related inquiries, 1) the search for male reproductive structures and 2) hybridization with related species are worthwhile. Quantification of the nuclear DNA of nine Halophila taxa was conducted to better understand interspecific genome size variation within the genus. Results suggest that three polyploidy events may have accompanied evolution in this genus. Data for 2C and 4C values are reported with H. engelmanii having the largest content of 2C = 27 pg and H. stipulacea having the lowest, 2C = 7.5 pg.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Keywords
Halophila--Florida, Seagrasses--Florida, Stains and staining (Microscopy)
Subjects
Halophila -- Florida
Seagrasses -- Florida
Stains and staining (Microscopy)