Department of Biology, California State University, Northridge, CA, USA.
Adv Mar Biol. 2011;59:107-44. doi: 10.1016/B978-0-12-385536-7.00003-0.
The physiological mechanisms that regulate adaptive plasticity of clonal organisms are key to their success in changing environments. Here, we review the mechanisms that regulate morphological plasticity of colonial hydrozoans. There is a heritable, genetic basis to colony form, but environmentally-induced plasticity and self-reinforcing developmental physiology explain much of total phenotypic variance. Morphological development of colonial hydrozoans emerges from interactions among (1) behaviors which drive gastrovascular transport, (2) architecture of the gastrovascular system that determines hydrodynamic characteristics of vascular flow, and, (3) gene products that vary in response to physiological signals provided by gastrovascular transport. Several morphogenetic signaling mechanisms have been identified, including, reactive oxygen species and nutrient concentrations in the hydroplasm, and hydromechanical forces associated with gastrovascular transport. We present a conceptual model of the interacting forces that drive hydrozoan morphological development. Several avenues for future research are suggested by the synthesis of information from prior studies of hydrozoans. Elucidating the morphogenetic signaling pathways responsive to metabolites or hydromechanical forces and the epigenetic effect of vascular architecture on colony form may give new insight into the self-maintenance of indeterminately growing and continuously developing vascular systems.
调节克隆生物适应可塑性的生理机制是它们在变化环境中成功的关键。在这里，我们回顾了调节群体水螅动物形态可塑性的机制。虽然群体形式具有遗传基础，但环境诱导的可塑性和自我增强的发育生理学解释了大部分总表型变异。群体水螅动物的形态发育源自于以下因素之间的相互作用：（1）驱动肠腔运输的行为，（2）肠腔系统的结构决定了血管流动的流体动力学特征，以及，（3）对由肠腔运输提供的生理信号作出响应的基因产物。已经确定了几种形态发生信号机制，包括，水腔中的活性氧和营养浓度，以及与肠腔运输相关的水动力力。我们提出了一个概念模型，阐述了驱动水螅动物形态发育的相互作用力。通过对水螅动物的先前研究信息进行综合，提出了几个未来研究的途径。阐明对代谢物或水动力力作出响应的形态发生信号通路，以及血管结构对群体形式的表观遗传效应，可能会深入了解不定生长和持续发育的血管系统的自我维持。
