The effect of UV-B radiation and humic substances on growth and motility of the flagellate, Euglena gracilis.

• The effects of ultraviolet-B radiation (UV-B, 250–315 nm) were determined on Euglena gracilis with respect to speed, phototactic orientation, specific growth rate, and in the presence of humic substances. Humic substances had a protective effect when studying the speed and specific growth rate. However, the degree of phototactic orientation decreased in UV-B radiation both with and without humic substances. The inhibition of O2 evolution and speed was most pronounced when using cutoff filters WG280 and WG295. The photosynthetic inhibitor DCMU (10–6 M) did not have any effect on the speed, but the 02 evolution decreased to zero. The effect of different wavelengths in the UV-B region on the speed of E.gracilis showed the maximum sensitivity at 280 and 290 nm.

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

humic substances

Biology

Biologi

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