Specificity of the Antheridogen from Ceratopteris thalictroides (L.) Brongn.

Abstract

Characteristics of the fern antheridogen from Ceratopteris thalictroides (L.) Brongn. are investigated. These are: (a) determination of molecular size (it is readily dialyzable), (b) pK. (about 5), (c) movement in thin layer chromatography, and (d) ability to induce dark germination of fern spores. These four characteristics are compared to the same characteristics of three other antheridogens (antheridogens A and B or GA). Molecular size and pK1 are similar, but, the antheridogens are separable from each other using thin layer chromatography. It was also shown that spore germination is not induced by the Ceratopteris antheridogen, even in its own spores, a characteristic not reported as shared by the other antheridogens. However, the inconsistency of spore germination as an assay for antheridogen is demonstrated. The presence of gametophyte-produced ailelopathic substances is also shown.Hormonal induction of the male gametangium in ferns was first described by Dopp (3). He was able to induce antheridia precociously in Dryopteris filix-mas and Pteridium aquilinum. Such hormonal induction of fern antheridia is now a widely documented occurrence (see ref. 8, for review). Such an induction system is called an antheridogen system. An antheridogen system has recently been described for the fern, Ceratopteris thalictroides (13,14). In addition to inducing antheridia, the Ceratopteris antheridogen also induces a male gametophyte morphology. In the absence of hormone, a hermaphroditic morphology develops. These two morphologies are mainly defined on the basis of the type(s) of gametes formed by the gametophytes (14). The (5) was used throughout. Antheridogen Source Cultures. These cultures were aseptically established using 5 mg spores/500 ml medium in 2000-ml cotton-stoppered flasks. Cultures were grown under continuous cool white fluorescent light (about 300 ft-c), at room temperature for 4 weeks, then harvested.Bioassays. Aseptic multispore cultures were again used. Each employed 3 drops of sterile spore suspension (1 mg spores/2 ml tap water). Cultures were established in dilution series. Antheridogen-containing medium was Millipore-filtered and diluted into autoclaved, fresh medium (dark germination assays) or diluted into fresh medium before autoclaving (pK. and dialysis assays). Cultures were grown under continuous red light (pK8, dialysis and most chromatography assays) or continuous darkness (dark germination and some chromatography assays) for approximately 10 days, at room temperature. Cultures were examined microscopically for antheridium-inducing or dark germination-promoting abilities. The dark germination cultures were kept closed during observations. transferred to continuous red light for 2 weeks, when they were examined for spore germination and presence of antheridiate gametophytes. Spore Sterilization and Sowing. A quantity of spores was placed in the bottom of a 15-ml glass centrifuge tube. Wetting agent (2 drops Tween 20/100 ml distilled H20) was added. The spores were shaken into a ...

Insights into the evolutionary history and widespread occurrence of antheridiogen systems in ferns

“…As dark germination may take longer than germination under normally illuminated conditions (Weinberg & Voeller, 1969), it is possible that AG‐induced dark germination would have been observed at a later point. Finally, Ceratopteris thalictroides does not induce germination in darkness (Schedlbauer, 1976). Spores of Ceratopteris generally do not germinate in darkness, although some exceptions have been reported (Scott & Hickok, 1987).…”

Effect of red light and gibberellic acid on lipid metabolism in germinating spores of the fern Anemia phyllitidis

“…In A. phyllitidis and other schizaeaceous fern spores, germination can be stimulated also in the dark by certain antheridiogens (Schraudolf 1962, Naf 1966). This does not apply, however, for the antheridiogen of Ceratopteris thalictroides (Schedlbauer 1976). The schizaeaceous antheridiogens which can substitute for the light requirement can be replaced by gibberellic acid (GA;Schraudolf 1962, Voeller 1971-Naf 1966, which is structurally related to the native antheridiogen oiA.…”

Evidence for a Gibberellin Biosynthetic Origin of Ceratopteris Antheridiogen

“…However, all antheridiogens apparently share some basic chemical properties, i.e. they are readily dialyzable and of low mol wt (<2000), possess a pKa of about 5.0, and are relatively stable at pH and temperature extremes (25).…”