Abstract. Polyploidization has been traditionally considered a phenomenon that mediates ecological differentiation; however, the adaptive value of genome duplications has been seldom explored. Natural or synthetic polyploids offer unique opportunities to experimentally quantify the immediate consequences of genome duplications in plant traits that may be involved with ecological differentiation. Jasione maritima is a diploid-tetraploid complex with cytotypes distributed allopatrically in an environmental gradient ideal for exploring the role of genome duplications in the success of polyploid lineages. However, like in numerous other polyploid complexes, neotetraploids of J. maritima have not been found in nature. In this study we developed a methodology to obtain synthetic tetraploids from seeds collected in wild diploid plants of J. maritima. We tested the effect of different colchicine concentrations and seedling ages in survival and polyploidization success of J. maritima seedlings, using flow cytometry to assess ploidy level and considering the population of origin. A methodology to synchronize seed germination was also explored. Synchronization of seed germination was best achieved using a cold treatment of 2 weeks before the transference to a growth chamber. An overall survival rate of 11.5±0.7 % and further tetraploid conversion of 35.6±2.9 % was obtained using 3-day-old seedlings of J. maritima. Survival rates were variable depending on colchicine treatment (the highest the most lethal) and seedling origin (i.e. population), while conversion rate was similar across these factors and high rates of tetraploid conversion were obtained. Considering that the main constraint was survival to the colchicine treatment, we suggest the use of the lowest colchicine concentration tested, i.e. 0.1 % colchicine. The use of older seedlings increased survival rates but, in many cases, compromised a complete tetraploid conversion, generating many diploid-tetraploid mixoploid plants.

中文翻译：

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合成四倍体的生产作为多倍体研究的工具

摘要。传统上，多倍化被认为是一种介导生态分化的现象。然而，很少探索基因组重复的适应性价值。天然或合成的多倍体提供了独特的机会，可以通过实验量化可能与生态分化有关的植物性状基因组复制的直接后果。Jasione maritima 是一种二倍体-四倍体复合体，其细胞型在环境梯度中异源分布，非常适合探索基因组重复在多倍体谱系成功中的作用。然而，像在许多其他多倍体复合物中一样，J. maritima 的新四倍体尚未在自然界中被发现。在这项研究中，我们开发了一种方法来从 J. maritima 的野生二倍体植物中收集的种子中获得合成四倍体。我们测试了不同秋水仙碱浓度和幼苗年龄对海胆藻幼苗存活和多倍化成功的影响，使用流式细胞术评估倍性水平并考虑起源种群。还探索了同步种子萌发的方法。在转移到生长室之前使用 2 周的冷处理可以最好地实现种子发芽的同步。使用 3 天龄的海胆藻幼苗获得了 11.5±0.7% 的总存活率和 35.6±2.9% 的进一步四倍体转化率。存活率因秋水仙碱处理（最高最致死率）和幼苗来源（即种群）而异，而这些因素的转化率相似，并且获得了高四倍体转化率。考虑到主要限制因素是秋水仙碱治疗的存活率，我们建议使用测试的最低秋水仙碱浓度，即 0.1% 秋水仙碱。使用较老的幼苗提高了存活率，但在许多情况下，会损害完整的四倍体转化，产生许多二倍体-四倍体混合倍体植物。