ИСТИНА

Hydroplasmic flow (HF) is clearly visible in most colonial hydroids with transparent or translucent body walls. The hydroplasm tends to reverse its flow as it moves along the coenosarc tube, alternating between opposite directions. It is difficult to study the transport system in colonial hydroids without simultaneous recording of HF in different parts of the highly branched colony. We have developed a method for integrated characterization of the transport system using video data collected in a single location in the transport system. Video recording is conducted at the frame rate of 4 to 30 FPS. When processing the results, both the lumen diameter in two cross-sections of the coenosarc within the same frame and the rate of particle flow in the hydroplasm are taken into account. These data help to factor in the dynamic aspects of the following parameters: the rate and direction of HF; the presence/absence of peristaltic waves of contraction/expansion of the coenosarc; the volume of transported hydroplasm; the distance of particle transfer in a single cycle of HF. The combination of these parameters makes for sufficiently detailed characterization of the transport system in general, and its reaction to experimental impact. We have used this method to explore the frequency of coenosarc pulsations, the rhythm and range of HF, and the level of colony integration. The study was supported by RFBR grant No. 11-04-00994-a.