Tisshaw Kathryn, Freeland Joanna, Dorken Marcel
Environmental and Life Sciences Graduate Program Trent University Peterborough ON Canada.
Department of Biology Trent University Peterborough ON Canada.
Ecol Evol. 2020 Oct 1;10(21):12091-12103. doi: 10.1002/ece3.6831. eCollection 2020 Nov.
Hybrids of a single pair of parent species can be much more common in some geographical regions than in others. The reasons for this are not well understood, but could help explain processes such as species diversification or the range expansion of invasive hybrids. The widespread cattails and seldom hybridize in some parts of their range, but in other areas produce the dominant hybrid . × . We used a combination of field and greenhouse experiments to investigate why . × has invaded wetlands in the Laurentian Great Lakes region of southern Ontario, Canada, but is much less common in the coastal wetlands of Nova Scotia (NS) in eastern Canada. One potentially important environmental difference between these two regions is salinity. We therefore tested three hypotheses: (1) and in NS are genetically incompatible; (2) the germination or growth of . × is reduced by salinity; and (3) a main competitor of . × , is locally adapted to saline conditions in NS. Our experiments showed that NS and are genetically compatible, and that saline conditions do not impede growth of hybrid plants. However, we also found that under conditions of high salinity, germination rates of hybrid seeds were substantially lower than those of NS . In addition, germination rates of NS were higher than those of Ontario suggesting local adaptation to salinity in coastal wetlands. This study adds to the growing body of literature which identifies the important roles that local habitat and adaptation can play in the distributions and characteristics of hybrid zones.
单一亲本物种的杂交种在某些地理区域可能比其他区域更为常见。对此的原因尚未完全了解，但这有助于解释物种多样化或入侵杂交种范围扩张等过程。广泛分布的香蒲在其分布范围的某些地区很少杂交，但在其他地区产生了占主导地位的杂交种×。我们结合了田间试验和温室试验来研究为什么×入侵了加拿大安大略省南部劳伦琴大湖地区的湿地，但在加拿大东部新斯科舍省（NS）的沿海湿地却不那么常见。这两个地区之间一个潜在的重要环境差异是盐度。因此，我们测试了三个假设：（1）NS中的和在基因上不兼容；（2）盐度会降低×的发芽率或生长；（3）作为×的主要竞争者，在当地适应了NS的盐碱条件。我们的实验表明，NS中的和在基因上是兼容的，并且盐碱条件不会阻碍杂交植物的生长。然而，我们还发现，在高盐度条件下，杂交种子的发芽率大大低于NS中的。此外，NS中的发芽率高于安大略省中的，这表明其在沿海湿地对盐度有局部适应性。这项研究增加了越来越多的文献，这些文献指出了当地栖息地和适应性在杂交区的分布和特征中可以发挥的重要作用。
