Dudgeon S, Wagner A, Vaisnys J R, Buss L W
Department of Biology, California State University, Northridge, California 91330-8303.
Biol Bull. 1999 Feb;196(1):1-17. doi: 10.2307/1543161.
Time-lapse video microscopy and image analysis algorithms were used to generate high-resolution time series of the length and volume of a single hydrozoan polyp before and after feeding. A polyp of Podocoryne carnea prior to feeding is effectively static in length and volume. At 20{deg}C, feeding elicits 8-millihertz (mHz) oscillations in polyp length and volume. A polyp connected to a colony by a single stolon displayed an abrupt transition from low-amplitude, 8-mHz oscillations to large-amplitude, 6-mHz oscillations at 1.5-2 h after feeding. The transition was preceded by a substantial decrease in polyp volume and increase in length which coincided with the export of food items from the digestive cavity of the polyp into the colonial gastrovascular system. In contrast, 8-mHz oscillations of a polyp isolated from a colony continued for 12.7 h after feeding, at which time particulates from the digestive cavity were exported into the hydrorhiza and a 4-mHz subharmonic became briefly dominant. Regular oscillatory behavior was terminated by regurgitation at comparable intervals post-feeding in coupled and isolated polyps. These observations are compatible with the hypothesis that the presence of nutrients in the digestive cavity induces polyp oscillations and that release of nutrients into the gastrovascular system similarly induces unfed polyps to oscillate, thereby distributing the contents of the fed polyp throughout the colony.
采用延时视频显微镜和图像分析算法，生成了单个水螅虫息肉在进食前后长度和体积的高分辨率时间序列。未进食时，卡氏柄管水母的息肉在长度和体积上基本保持静止。在20℃时，进食会引发息肉长度和体积的8毫赫兹（mHz）振荡。通过单个匍匐茎与群体相连的息肉在进食后1.5 - 2小时，显示出从低振幅8 mHz振荡到高振幅6 mHz振荡的突然转变。转变之前，息肉体积大幅减小，长度增加，这与食物从息肉消化腔进入群体胃血管系统的过程同时发生。相比之下，从群体中分离出的息肉在进食后8 mHz振荡持续了12.7小时，此时消化腔中的颗粒物质被排出到根状茎中，4 mHz的次谐波短暂占主导地位。在进食后的相当间隔时间，耦合和分离的息肉通过反流终止了有规律的振荡行为。这些观察结果与以下假设相符：消化腔中营养物质的存在会诱发息肉振荡，营养物质释放到胃血管系统中同样会诱发未进食的息肉振荡，从而将进食息肉的内容物分布到整个群体中。
