Influence of microfilament and microtubule inhibitors applied by immersion and microinjection on circulation streaming in the staminal hairs ofTradescantia blossfeldiana

Summary Reaction of cytoplasmic streaming inTradescantia staminal hairs to microfilament and microtubule specific inhibitors, applied either by conventional immersion or by microinjection, indicates that both the actin-myosin and the microtubule system may be involved in driving the particle stream. Cytoplasmic streaming was stopped at relatively high drug concentrations when the cells were immersed in the inhibitor solution. Microinjection of defined concentrations of inhibitor into single, selected cells were effective at concentrations at least two orders of magnitude lower. Further reduction of inhibitor concentrations, however, enhanced streaming up to 100%. When a mixture of cytochalasin D and oryzalin were injected at concentrations that had previously been shown to enhance particle movement, very efficient inhibition occurred and streaming rapidly stopped. Adjacent cells on both sides of the injected cell were also affected: within a few minutes of the injection of microfilament inhibitors the basal cell reacted, followed slightly later by the apical one; microtubule inhibitors caused a reaction in the apical cell earlier than in the basal cell. The results are discussed with respect to the involvement of actin and myosin microfilaments, as well as microtubules, as force generating systems of particle movement.Abbreviations CB cytochalasin B - CD cytochalasin D - Cys cysteine - DMSO dimethylsulfoxid - DTT dithiothreitol - MI microinjection - NBD 7-nitrobenz-2-oxa-1,3-diazole - NEM N-ethylmaleimide Nocodazole methyl 5-(2-thienylcarbonyl)-1 H-benzimidazol-2-yl]carbamate