Higher frequency of legitimate pollinators and fruit set of autotetraploid trees of Libidibia ferrea (Leguminosae) compared to diploids in a mixed tropical urban population
Higher frequency of legitimate pollinators and fruit set of autotetraploid trees of Libidibia ferrea (Leguminosae) compared to diploids in a mixed tropical urban population
复制标题
与混合热带城市种群中的二倍体相比，合法授粉者和同源四倍体豆科树的果树频率更高
作者：
Willams Oliveira;J. L. Silva;Oswaldo Cruz;Marcela Tomaz P Oliveira;Isabelle Fernandes de Albuquerque;L. A. Borges;A. Lopes
在混合倍性群体中，新形成的多倍体最初出现的频率较低，与二倍体相比。然而，多倍体可能会导致形态和物候的变化，促进生殖隔离，有利于多倍体的建立和繁殖成功。此外，先前的研究表明，多倍体可以赋予生物体在压力环境中的一些适应优势。在这里，我们调查的繁殖物候期，花性状和繁殖成功的二倍体和同源四倍体树的Libidibia ferrea（Mart。Ex Tul.）L. P. Queiroz（Legumande）在一个混合的热带城市人口，一个紧张的环境。我们评估了倍性水平，开花和结果的物候，开花同步，花和生殖生物学，授粉和结果和结实。我们测试的假设，同源四倍体个体有较高的频率授粉和较高的水果和种子集每花序（作为生殖成功的代理）比二倍体在城市绿色空间。Libidibia ferrea是检验我们假设的一个很好的模型，因为它是自交不亲和的（即依赖传粉者坐果）。在研究的城市生态系统中，二倍体花龄为6-7个月/年，同源四倍体花龄为3-5个月/年。同源四倍体和二倍体在花期上有一定的重叠，但二倍体单独开花的时间只有2-3个月。同源四倍体有显着更多的花每花序，更大的花和更大的花粉粒（如预期的多倍体），但也有更高的频率访问合法的传粉者，包括两个排他性的，更高的果实和种子集每花序相比，二倍体，尽管有一个较短的花期。我们的研究结果揭示了在热带城市绿色空间中多倍体相对于其相关二倍体的一些优势。此外，我们的研究结果强调，需要更多的研究，寻求了解非生物机制影响城市生态系统中的多倍体生殖输出。
In mixed-ploidy populations, newly formed polyploids initially occur at low frequencies when compared to diploids. However, polyploidy may lead to morphological and phenological changes, which promote reproductive isolation and favor polyploid establishment and reproductive success. Additionally, previous studies have shown that polyploidy can confer some adaptive advantages to organisms in stressful environments. Here, we investigate variation in reproductive phenology, floral traits and reproductive success between diploid and autotetraploid trees of Libidibia ferrea (Mart. Ex Tul.) L.P. Queiroz (Leguminosae) in a mixed tropical urban population, a stressful environment. We assessed ploidy levels, flowering and fruiting phenology, flowering synchrony, floral and reproductive biology, pollination and fruit and seed set. We tested the hypothesis that autotetraploid individuals have a higher frequency of pollinators and higher fruit and seed set per inflorescence (as a proxy of reproductive success) than diploids in an urban green space. Libidibia ferrea is a good model to test our hypothesis because it is self-incompatible (i.e. relies on pollinators to set fruits). In the urban ecosystem studied, we found that diploids flowered for 6–7 months/year and autotetraploids for 3–5 months/year. Flowering synchrony was low between and within cytotypes and even though autotetraploids and diploids exhibited some overlap in flowering period, diploids flowered alone for 2–3 months. Autotetraploids had significantly more flowers per inflorescences, larger flowers and larger pollen grains (as expected for polyploids), but also a higher frequency of visits by legitimate pollinators including two exclusive ones, and higher fruit and seed set per inflorescence when compared to diploids, despite having a shorter flowering period. Our findings reveal some advantages for polyploids over their related diploids in a tropical urban green space. Also, our results highlight the need for more studies that seek to understand abiotic mechanisms affecting reproductive output of polyploids in urban ecosystems.
影响因子：
4.2
作者：
Karunarathne, Piyal;Schedler, Mara;Hojsgaard, Diego
通讯作者：
Hojsgaard, Diego