Differentiation of germination characteristics in Scutellaria rubropunctata (Lamiaceae) associated with adaptation to rheophytic habitats in the subtropical Ryukyu Islands of Japan
Differentiation of germination characteristics in Scutellaria rubropunctata (Lamiaceae) associated with adaptation to rheophytic habitats in the subtropical Ryukyu Islands of Japan
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红斑黄芩（唇形科）发芽特征的分化与日本亚热带琉球群岛流变生境的适应相关
DOI：
10.1007/s10265-019-01103-z
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发表时间：
2019
影响因子：
2.8
通讯作者：
Denda T
中科院分区：
文献类型：
--
作者：
Yoshimura H;Arakaki S;Hamagawa M;Kitamura Y;Yokota M;Denda T
在15 °C、20 °C、25 °C和30 °C的温度下，研究了兼性红点轮枝藻（Rheophyteacrubropunctata）种子的萌发特性。流生型红点酸浆在所有温度下均具有较高的萌发率和相对同步的萌发时间。这种特性可以使它快速建立而不受温度的影响，通过避免种子被上涨的水冲走而在流生植物栖息地中获得生存优势。相反，陆生型红点紫珠和同属种印度紫珠的最终发芽率在15 °C时最高，在30 °C时急剧下降。这两种在较高温度下保持不发芽的植物的种子在温度改变到15 °C后不久就发芽了，这表明发芽抑制是一种强制休眠状态，在转移到最佳温度后被释放。这些特点表明，异步发芽，这被认为是减少波动环境中的干扰的风险。我们的研究可能是第一个证明种子萌发特性的分化有关的适应流生生境。由于流生植物在强烈的选择压力下占据如此恶劣的环境，许多其他的流生植物可能发生种子萌发特性的适应性分化。
Seed germination characteristics of a facultative rheophyteScutellaria rubropunctata, a perennial skullcap endemic to the subtropical Ryukyu Islands of Japan, were investigated at temperatures of 15 °C, 20 °C, 25 °C, and 30 °C. The rheophytic type ofS.rubropunctatashowed relatively simultaneous germination times and reached high germination rates under all temperatures tested. This characteristic may allow it to establish quickly without being influenced by temperature, giving a survival advantage in rheophytic habitats by avoiding seeds being washed away by the rising water. In contrast, the final germination rate of the terrestrial type ofS.rubropunctata, as well as that of the congenerS.indicavar.parvifolia, was highest at 15 °C and declined drastically at 30 °C. Seeds of both of these plants that remained ungerminated at higher temperatures germinated soon after the temperature was changed to 15 °C, indicating that the germination suppression was a state of enforced dormancy that was released after transfer to the optimal temperature. These characteristics suggest an asynchronous germination which is thought to reduce the risk of disturbance in fluctuating environments. Our study may be the first to demonstrate the differentiation of seed germination characteristics in relation to adaptations to a rheophytic habitat. Because rheophytes occupy such a harsh environment under strong selective pressure, the adaptive differentiation of seed germination characteristics may occur in many other rheophytes.