[Spatio-temporal analysis of contraction dependent surface movements in Physarum polycephalum (author's transl)]

Plasmodial veins of Physarum polycephalum were investigated by combining cinematographical and tensiometrical methods. Veins remaining on their original growing substrate show characteristic surface movements resulting from an intrinsic contraction automaticity. Radial and longitudinal components of surface movements were registered simultaneously. Both contraction activities show identical frequencies, in contrast to results derived from experiments with isolated veins. There is only one genuine frequency and therefore one has not necessarily to suppose the existence of a cooperation of two oscillating systems underlying the rhythmic contraction phenomena. The results are discussed in respect to the basis of the contraction phenomena: the cytoplasmic actomyosin fibrils of Physarum and their function in motive force generation for protoplasmic streaming.