Baack E J
Center for Population Biology, University of California, One Shields Avenue, Davis, CA 95616, USA.
Heredity (Edinb). 2005 May;94(5):538-46. doi: 10.1038/sj.hdy.6800656.
Newly formed tetraploid plants in sympatry with their diploid progenitors should face significant obstacles to persistence and population establishment because of low-fitness triploids formed by cross-ploidy pollinations. Prior models have found restrictive conditions for a minority tetraploid subpopulation to persist. A stochastic spatial model, parameterized using snow buttercups (Ranunculus adoneus), was used to examine the influence of limited seed and pollen dispersal distances on the success of minority tetraploids and the interaction of these factors with different rates of self-pollination and tetraploid advantage. Higher rates of self-pollination and increased tetraploid advantage increase the probability of tetraploid persistence. Limiting the dispersal of seeds and pollen further increases the positive impact of any given level of self-pollination and tetraploid advantage. Taxa with short-distance seed and pollen dispersal should face much less stringent barriers to sympatric polyploid speciation than taxa with long-distance dispersal patterns. With short-distance seed and pollen dispersal, polyploid speciation should be possible in the absence of ecological differentiation or recurrent polyploid formation through unreduced gametes.
新形成的四倍体植物与其二倍体祖先同域共存时，由于异倍体授粉形成的低适应性三倍体，它们在持续存在和种群建立上面临重大障碍。先前的模型已经发现少数四倍体亚种群持续存在的限制条件。使用雪毛茛（毛茛属）进行参数化的随机空间模型，用于研究有限的种子和花粉传播距离对少数四倍体成功的影响，以及这些因素与不同自花授粉率和四倍体优势的相互作用。较高的自花授粉率和增加的四倍体优势会增加四倍体持续存在的概率。限制种子和花粉的传播进一步增加了任何给定水平的自花授粉和四倍体优势的积极影响。与具有长距离传播模式的类群相比，种子和花粉传播距离短的类群在同域多倍体物种形成上面临的障碍要宽松得多。在种子和花粉传播距离较短的情况下，即使没有生态分化或通过未减数配子反复形成多倍体，多倍体物种形成也是可能的。
