Degree Type


Date of Award


Degree Name

Doctor of Philosophy




Spore germination and antheridiogen chemistry were studied in Anemia mexicana Klotzsch. Light and scanning electron microscopy were used to study the cell division pattern during germination and early gametophyte development. The spore cell undergoes two asymmetric divisions. The first division gives rise to a rhizoid while the second gives rise to a protonemal cell. The spore cell remains metabolically active and may undergo a third division to form a cell which remains almost entirely within the spore coat;Effects of several cultural and chemical treatments on spore germination and early gametophyte development were studied in A. mexicana and Anemia phyllitidis (L.) Swartz. Spore germination in both species has a pH optimum of 5-6.5. After an eight hour photoinsensitive phase, both species require at least 16 hours of light to induce 50% spore germination. Spores of A. phyllitidis are at least 100 times more sensitive to gibberellin (GA)- induced germination in the dark. The relative order of sensitivity of the two ferns to GAs is the same with GA(,4) and GA(,7) exhibiting the highest activity, GA(,3) intermediate and GA(,13) least effective. Each species is 100 times more sensitive to its own antheridiogen. Mevalonic acid, kaurene and kaurenoic acid did not stimulate germination in the dark. Inhibitors of GA biosynthesis did not inhibit light-induced germination. AMO-1618 (1 mM) had little effect on gametophyte development; fenarimol (1 mM) inhibited gametophyte growth. Ancymidol (0.1 mM) caused gametophytes to be round in shape with expansion of the cells in width as compared to length;The structure of A. mexicana antheridiogen was partially characterized by mass spectrometry and infrared spectrometry. This new antheridiogen is a C-19 GA-like compound with one hydroxyl group, one carboxylic acid group, a lactone ring, an exocyclic methylene carbon and one ring double bond. Mass spectral data indicate it is not GA(,5), GA(,7), GA(,31), or GA(,62).



Digital Repository @ Iowa State University,

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Joan Elizabeth Nester



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104 pages

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Botany Commons