SCHNELLER, JAKOB1*, HANS GERBER2, and ALEX ZUPPIGER1. 1Institute of Systematic Botany, Zollikerstrasse 107, CH-8700 Zürich, Switzerland; 2Laboratory for Biomechanics, Swiss Federal Institute of Technology Zürich, CH-8092 Zürich, Switzerland. - Spore dispersal mechanisms in Selaginella. A fascinating case of bioballistics.
The first investigation of the active spore dispersal in
Selaginella was published by the German botanist K. Goebel
(1901). A bit more than a decade ago Page (1989) published a paper on
the so called compression and slingshot mechanism in megaspore
dispersal unaware of Goebel's publication. The goal of our
investigation was to closely analyze the mechanisms which allow the
active spore dispersal of micro- and megaspores. When using a regular
video-camera the initial stages of spore dispersal cannot clearly be
resolved due to the high speed of the ejected spores. When using a
high speed video camera (1000 pictures per second) a better resolution
became possible and the take off of the megaspores can be seen. The
distance megaspores can be shot was between a few centimeters (only a
minority of the megaspores) and a maximum of 55 cm with a mean of
about 25 cm. In contrast to the megaspores, the microspores are
actively dispersed; they are spread only a few millimeters to
approximately 3 cm. We will present a few different video sequences,
which show the movements of the sporangium wall and the first step of
the spore dispersal and discuss a few preliminary results obtained by
our investigation. [Goebel, K. 1901. Archegoniatenstudien IX.
Sporangien, Sporenverbreitung und Blüthenbildung bei
Selaginella. Flora 88: 201.228. Page, C.N. 1989. Compression
and slingshot megaspore ejection in Selaginella selaginoides.
Fern Gaz. 13: 257-266.]
Key words: pteridophytes, Selaginella, spore dispersal