Effect of GeO 2 on embryo development and photosynthesis in Fucus vesiculosus (Phaeophyceae)

摘要: Germanium dioxide (GeO2) has been used for many years in the cultivation of red and green algae as a means controlling growth diatoms. Brown are sensitive to GeO2, however, basis this sensitivity not characterized. Here we use embryos Fucus vesiculosus investigate morphological physiological impacts GeO2 toxicity. Morphometric features were measured microscopically, determined using pulse amplitude modulated (PAM) fluorometry. At 5 mg L -1 grew slower than controls developed abnormalities. After 24 h, initial zygote divisions often oblique rather transverse. Rhizoids had inflated tips GeO 2 less branched, apical hairs deformed, with irregularly aligned, spheroidal cells. Minimum fluorescence ( F0) showed minor differences over 10 days experiment, pigment levels (chlorophylls a, c total carotenoids) no difference after days. Optimum quantum yield increased from ca. 0.52 at h 0.67 days, GeO2-treated higher mean values (significant 3 days). photosystem II (ΦPSII) was stable control thalli but declined significantly 2. Addition silica (as SiO2) did reverse effects GeO2. These results suggest that toxicity brown is associated negative cytological level metabolic photosynthesis.