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Cellular fatty acids of 10 strains of lactic acid bacteria were analyzed. The purpose of this work was to find lactic acid bacteria with high lactobacillic acid contents. The bacteria studied were unable to synthesize oleic acid. Some strains did not synthesize lactobacillic acid, although all were able to form dihydrosterculic acid. Twenty-one to thirty-four percent of the fatty acid content of Lactobacillus fermentum and L. buchneri was lactobacillic acid, and these species were chosen for future studies of environmental factors affecting cyclopropane fatty acid synthesis.

Cultivation of Catharanthus roseus hairy root cultures at different temperatures was found to have an effect on growth rate and indole alkaloid content as well as lipid composition. When lowering the temperature, the roots responded by increasing the degree of unsaturation of cellular lipids, which was mainly due to an increased proportion of linolenic acid in the main lipid classes. The modifications in lipid composition were obviously necessary for the roots to retain the proper cell membrane fluidity at each temperature. Despite of changes in membrane lipids, no effect on the distribution of indole alkaloids between the roots and the medium could be detected. Instead, the level of alkaloid accumulation showed a clear increase with lowering temperature.

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The molds Botrytis cinerea, Cladosporium cladosporioides, and the yeast Aureobasidium pullulans, isolated from the leaves of three short-rotation Salix clones, were found to produce indole-3-acetic acid (IAA). Abscisic acid (ABA) production was detected in B. cinerea. The contents of IAA and ABA in the leaves of the Salix clones and the amounts of fungal propagules in these leaves were also measured, in order to evaluate whether the amounts of plant growth regulators produced by the fungi would make a significant contribution to the hormonal quantities of the leaves. The content of ABA, and to a lesser degree that of IAA, showed a positive correlation with the frequency of infection by the hormone-producing organisms. The amounts of hormone-producing fungi on leaves that bore visible colonies were, however, not sufficiently high to support the claim that either the fungal production of ABA or IAA would significantly contribute to the hormonal contents of the leaves of the Salix clones. It is therefore suggested that the effect of fungal IAA production on plants is limited to the rhizosphere and that B. cinerea, which is a known pathogen, induces ABA production by the mother plant as a response to physiological stress.