Über die photosensible Phase der Polaritätsinduktion bei Equisetumsporen und Fucuszygoten

Abstract

Summary The time course of photopolarizability (PSP) has been studied at different temperatures on populations of germinating spores of the archegoniate Equisetum variegatum (fig. 1) and fertilized eggs of the brown alga Fucus serratus (fig. 3) using irradiation with unilateral unpolarized, respectively, linearly polarized monochromatic blue light. The technique of intermittent, especially counteracting irradiation has been employed to gain information on the experimentally directly inaccessable PSP of the single spore, respectively, egg. Our results suggest for this parameter to be about 2 hours in Equisetum (fi. 2), and 1 hour in Fucus (fig. 4), that is, in any case only a fraction of the population's PSP which thence reflects a frequency distribution of the cellular PSP. The PSP of the populations turned out to be temperature-dependent; for instance, increasing the temperature apparently synchronizes the Equisetum spore population with regard to its PSP (fig. 1), while our experiments showed no influence of the temperature upon the PSP of the single spore (fig. 2). Our results on the Fucus serratus egg help evaluate the significance of biophysical, biochemical, and physiological data of different authors concerning the still unknown mechanism of cell polarization, i.e. growth localization (fig. 6). We particularly exclude the transient membrane depolarization which was reported for different Fucus species, including Fucus serratus , to be a plausible candidate to organize the polarity at least in the latter instance, because this egg is photopolarizable at least 3 hours after the electric episode. For this event we tentatively propose a different morphogenetic significance using biochemical data by Linskens (1969) on Fucus vesiculosus , a species physiologically closely related to Fucus serratus . We also conclude that the protein synthesis pertinent to the rhizoid formation, as measured by Quatrano (1968; cf. fig. 6), occurs to early to be limited to the rhizoid pole.