The Influence of pH on the Cadmium‐Repressed Growth of the Alga Coelastrum proboscideum

Abstract

The inhibition of growth by different concentrations of CdCl2 in the range 4,5 × 10−7 to 5.6 × 10−7M was studied in the green alga Coelastrum proboscideum Bohlin in inorganic media at pH 4.3, 5.3 and 6.2. The factorial destgn of the experiments was evaluated as an analysis of 22 factors. Below pH 4.0 and above pH 6.5 growth was depressed without adding Cd. Cd concentrations exceeding 5.6 × 10−8M reduced algal growth significantly with a 50% inhibition at 5.6 × 10−7M Cd. The Cd concentration of 5.6 × 10−7M was less toxic at pH 6.2 than at pH 5.3 and 4.3, thus revealing a negative interaction between protons and Cd.

The influence of zinc and light conditions on the cadmium‐repressed growth of the green alga Coelastrum proboscideum

“…' Axenic cultures of the green alga Coelastrum proboscideum Bohlin (introduced by Witsch and Heussler 1970) were grown in a modified inorganic medium (Muller and Payer 1979) using techniques described by Soederefa/. 1967.…”

“…The algae were cultured in glass tubes of 25 ml volume at 31 ± 1°C in a 16:8 h lightrdark cycle or in a 24 h light cycle (continuous illumination). Six fluorescent lamps Osram L 65 W/22 R cool white de luxe produced an illumination of 20 klux (Muller and Payer 1979). The culture suspensions were diluted with fresh medium every 24 h at the onset of the light period, to give a standard dry matter concentration of 100 mg/1.…”

“…The absorbance of the cultures was measured in the culture tubes using a Medico photometer with Gibson filter 560 (Dr. Lange, Berlin) and served as a measure of growth (Muller and Payer 1979). Since the growth of this KLAUS W. MULLER AND HANS-D. PAYER Physiol.…”

“…The cultures with lowest Cd and Zn concentrations (Table 1, no. 1 and 10) served as controls; they contained Zn corresponding to the basic medium(Muller and Payer 1979) and Cd amounts, which originated only from unavoidable contaminations by chemicals, glassware, air, and water.Onlyunder conditions of Zn deficiency small amounts The influence of Cd and Zn on the light-dependent growth of Coelastrum proboscideum. First 3 columns: 16:8 h light-and-dark cycle; last 3 columns: 24 h continuous illumination.…”

Effects of Ph on Toxicity of Cadmium, Cobalt and Copper to the Green Alga Scenedesmus Bijuga

“…Both pH and redox potential can exert considerable effects on metal availabilities and ionization and thus the toxicity of heavy metals (Müller and Payer, 1979;Michnowiez and Weaks, 1984;Peterson et al, 1984;Campbell and Stokes, 1985;Vymazal, 1990;Vymazal, 1995). Furthermore, metal accumulation by algae is influenced by a number of abiotic and biotic factors, one of these being pH (Vymazal, 1995).…”