Ecological Significance of Brassinosteroids in three temperate ferns

Abstract

In this work, we contribute with the first essay devoted to relating the effect of brassinosteroids on the germination and development of fern spores of Pteridium aquilinum, Polystichum lonchitis and Pteris vittata. The effect of brassinosteroids (BRs) on the germination and development of fern spores is species-dependent. In the case of P. aquilinum, which is antheridiogen sensitive and in which rhizome reproduction predominates, BR treatment caused a negative effect over spore germination. For P. vittata, also antheridiogen sensitive and which forms large populations with sexual origin, BR treatment caused a slight negative effect on spore germination. Finally, for P. lonchitis, antheridiogen insensitive, the effect of BR treatment was positive. Thus, brassinosteroid application seems to regulate fern spore germination by modulating antheridiogen levels. Regarding further gametophyte development, the effects range from increasing the development velocity in P. lonchitis (which would aid the species in their reproductive role under adverse environmental conditions) to the independence in P. aquilinum and P. vittata (which, in general, live under less hard environmental conditions). Further research will be done in order to elucidate in detail the relationship between brassinosteroids, sexual organ expression and sporophyte production in the three species, considering at the time the use of antheridiogen system and the formation of apogamous plants. These results are providing valuable new information regarding the role of brassinosteroids on fern spore germination and growth as well as raising new questions for future studies.