Thallus mechanical strength, as well as production of secondary metabolites as defensive compounds, of tropical macroalgae is often essential for protection from herbivory. In tropical macroalgae, thallus mechanical strength is negatively correlated with productivity — a trade‐off between productivity and thallus toughness. The tropical fucoids, Turbinaria ornata which has defensive morphological traits against herbivory and Sargassum ilicifolium which is expanding its distribution in Japanese waters, were examined to determine thallus traits related to mechanical strength and productivity and their pair‐wise relationships were also examined. These traits that are directly or indirectly related to the trade‐off between productivity and thallus toughness were compared to data for various other temperate macroalgae by regression analyses. We found two strong positive correlations between thallus mechanical strength and thallus mass or thallus thickness, confirming that higher levels of mechanical strength for tropical fucoids is associated with higher biomass or thallus thickness. Also, negative correlations between thallus toughness and productivity were found indicating structural and physiological trade‐offs. However, the tropical fucoids exhibited relatively high productivity regardless of their higher level of thallus toughness. These traits of the tropical fucoids slightly deviate from the typical conservative strategy with higher thallus toughness and lower productivity as a trade‐off between productivity and thallus toughness.

中文翻译：

---

热带褐藻糖体的菌体力学和生理特性的表征：初步研究

热带大型藻类的菌体机械强度以及次生代谢物作为防御性化合物的产生对于防止食草动物的侵害通常是必不可少的。在热带大型藻类中，叶绿体机械强度与生产力负相关——这是生产力和叶绿体韧性之间的权衡。对热带岩藻类植物 Turbinaria ornata 具有防御食草动物的形态特征和正在扩大其在日本水域分布的马尾藻进行了检查，以确定与机械强度和生产力相关的叶状体特征，并且还检查了它们的成对关系。通过回归分析将这些与生产力和叶绿体韧性之间的权衡直接或间接相关的特征与各种其他温带大型藻类的数据进行了比较。我们发现菌体机械强度与菌体质量或菌体厚度之间存在两个强烈的正相关，证实热带岩藻糖体的机械强度较高与生物量或菌体厚度较高有关。此外，发现菌体韧性和生产力之间存在负相关，表明结构和生理之间的权衡。然而，热带褐藻糖胶表现出相对较高的生产力，而不管它们的叶状体韧性水平如何。热带褐藻糖胶的这些特征与典型的保守策略略有不同，后者具有较高的藻体韧性和较低的生产力，作为生产力和藻体韧性之间的权衡。证实热带岩藻糖体的较高机械强度与较高的生物量或叶状体厚度有关。此外，发现菌体韧性和生产力之间存在负相关，表明结构和生理之间的权衡。然而，热带褐藻糖胶表现出相对较高的生产力，而不管它们的叶状体韧性水平如何。热带褐藻糖胶的这些特征与典型的保守策略略有不同，后者具有较高的藻体韧性和较低的生产力，作为生产力和藻体韧性之间的权衡。证实热带岩藻糖体的机械强度较高与较高的生物量或叶状体厚度有关。此外，发现菌体韧性和生产力之间存在负相关，表明结构和生理之间的权衡。然而，热带褐藻糖胶表现出相对较高的生产力，而不管它们的叶状体韧性水平如何。热带褐藻糖胶的这些特征与典型的保守策略略有不同，后者具有较高的藻体韧性和较低的生产力，作为生产力和藻体韧性之间的权衡。热带褐藻糖胶表现出相对较高的生产力，而不管它们的叶状体韧性水平如何。热带褐藻糖胶的这些特征与典型的保守策略略有不同，它们具有较高的藻体韧性和较低的生产力，作为生产力和藻体韧性之间的权衡。热带褐藻糖胶表现出相对较高的生产力，而不管它们的叶状体韧性水平如何。热带褐藻糖胶的这些特征与典型的保守策略略有不同，后者具有较高的藻体韧性和较低的生产力，作为生产力和藻体韧性之间的权衡。