The effect of temperature on the growth rate of wild-type and mutant Chlamydomonas reinhardtii

Abstract

Chlamydomonas reinhardtii is a unicellular green alga with two flagella that facilitate its movement. This study investigates the effect of temperature on the growth rate of C. reinhardtii, as well as the differential effects on the CC-3913-pf9-3 mt- mutant compared to the CC-1690 wild type. Our method consisted of setting up samples of each strain under three temperature treatments (17°C, 20°C, 25°C) over 15 days. The data were obtained by measuring cell counts with a haemocytometer every three days, and the growth rate was calculated. A two-way ANOVA test followed this to obtain p values for each of our hypotheses. Our results of p₁ = 0.0001 provided support that increasing temperature will have an effect on thegrowth rate of C. reinhardtii. This was consistent with the literature, which suggests that higher temperatures cause C. reinhardtii to reach their maximum growth rate over a shorter time. The value p₂ = 0.03 provided support that the presence of a mutation will have an effect on the growth rate, because mutants without flagella have difficulty swimming to light sources for photosynthesis. Lastly, p₃ = 0.07 did not provide support that increasing the temperature would affect mutant and wild-type C. reinhardtii differently. This can be explained by the similarities between the mutant and wild-type cell cycles.