Untersuchungen über die photooxydative Farbstoffzerstörung und Stoffwechselhemmung bei Chlorellamutanten und panaschierten Oenotheren

Abstract

1. The influence of light on respiration, glucose uptake and pigment content was studied in the α- and β-carotin lacking Chlorella mutant 9 a isolated by Claes. The assimilation of glucose is inhibited even by very small amounts of blue light, while the consumption of O₂ and the pigment content remain unchanged. The pigments are destroyed only at higher intensities of light; along with it goes an increased consumption of O.,. Red light is much less effective than blue light. Normal photosynthesis could not be observed either by the manometric method or by using ¹⁴CO₂. 2. Under anaerobic conditions there is no destruction of pigments even at high intensities of light. The inhibition of oxidative assimilation, however, is only partly prevented, as shown by experiments on the assimilation of glucose in the dark after illumination under anaerobic conditions. 3. Also in variegated Oenothera strains, no matter whether they are the result of plastid mutation ¹ or of hybridisation. the bleaching can be prevented by the withdrawal of O₂. 4. The results correspond to the findings of Griffith and coworkers with blue green mutants of purple bacteria. The fact that in variegated Oenotheras carotin is present speaks against the assumption of these authors that photosensitiveness generally is caused by the deficiency of carotins. The stronger action of blue light indicates that also the carotins may have a photodynamic effect.