Abstract：
Spores have crucial importance in the establishment and development of seaweed populations. When the spore release matches with the low tidal period, they experience an extreme variation in the environmental conditions including the temperature. In this study, we assess the photosynthetic responses and growth of haploid (tetraspores) and diploid (carpospores) spores of two Gigartinales species (Mazzaella laminarioides and Iridaea cordata) from sub-Antarctic populations when exposed to an increasing temperature. In the laboratory, freshly released spores were exposed to a temperature gradient (7 [control], 10, 15, and 20 °C) recreating the temperature increase experienced by these spores during typical spring tides. Germination and further growth of spores previously exposed to temperature treatments were assessed. Carpospores and tetraspores exhibited variation in their photosynthetic response (measured as effective quantum yield; ΦPSII) to temperature increase. In Mazzaella laminarioides, only carpospores exhibited a reduction in ΦPSII (by 7-24% at 15-20 °C), while both types of spores of Iridaea cordata were sensitive to temperature increase (12-24% of ΦPSII reduction at 10-20 °C). Spores previously exposed to temperature treatments and maintained at 7 °C and low PAR germinated and developed in germlings. In general, germlings originated from carpospores pre-treated at high temperatures showed higher growth rates. The different responses to temperature increase exhibited by haploid and diploid propagules of both species highlight their ecophysiological capacity to face high-temperature variation ensuring successful recruitment survival.
摘要：
孢子在海藻种群的建立和发展中至关重要。当孢子释放与低潮期相匹配时，他们经历了包括温度在内的环境条件的极端变化。在这项研究中,我们评估了南极亚种群中两种Gigartinales物种（Mazzaellalaminarioides和Iridaeacordata）的单倍体（四孢子）和二倍体（孢子孢子）孢子的光合响应和生长。在实验室里,新鲜释放的孢子暴露于温度梯度(7[对照]，10、15和20°C）重新创建了这些孢子在典型的春季潮汐期间经历的温度升高。评估先前暴露于温度处理的孢子的发芽和进一步生长。Carpospore和四孢子对温度升高的光合响应（以有效量子产率测量；ΦPSII）表现出变化。在laminarioides中，只有Carpospore表现出ΦPSII的减少（在15-20°C时减少7-24％），而Iridaeacordata的两种孢子都对温度升高敏感（在10-20°C下ΦPSII减少的12-24％）。孢子先前暴露于温度处理并保持在7°C，低PAR发芽并在发芽中发育。总的来说,源自高温预处理的卡泊孢子的胚芽显示出更高的生长速率。两种物种的单倍体和二倍体繁殖体对温度升高的不同反应凸显了它们面对高温变化的生态生理能力，以确保成功的招募生存。
