Cytotype distribution at a diploid-tetraploid contact zone in Chamerion (Epilobium) angustifolium (Onagraceae)
Cytotype distribution at a diploid-tetraploid contact zone in Chamerion (Epilobium) angustifolium (Onagraceae)
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DOI：
10.1046/j.1469-8137.2004.00998.x
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发表时间：
1998-12-01
影响因子：
3
通讯作者：
Schemske, DW
中科院分区：
文献类型：
--
作者：
Husband, BC;Schemske, DW
在北美二倍体和四倍体Chamerion（以前的柳叶菜）angustifolium的地理分布在沿着北方森林南部边界和沿着落基山脉的狭窄区域内重叠。我们研究了频率和分布的二倍体和四倍体细胞型在一个狭窄的（5公里）区的同域性跨越海拔梯度和在puerecontium均匀的二倍体和四倍体的参考种群的Beartooth通行证，在落基山脉南部蒙大拿州北部怀俄明州。所有五个参考人群抽样占主导地位的一个单一的细胞型，但只有一个是完全一致的。在同域分布区，每隔2 m取样27条样带，共计238株植物。记录繁殖状态（营养状态、Bower芽、开放的花），并通过Bow细胞仪测定每株植物的倍性。二倍体和四倍体植物占主导地位（分别为36%和55%），但分布不均匀的横断面。27个样带中的6个被固定为单一细胞型（4个样带，二倍体; 2个样带，四倍体），并且在另外7个样带中二倍体或四倍体占优势（频率>75%）。三倍体占总样本的9%，最常见于含有二倍体和四倍体的样带（G = 3.4，df = 2，P = 0.07）。二倍体比三倍体或四倍体更经常繁殖（在芽中、鲍尔或果实中）（G = 12.0，df = 2，P < 0.001），并且是产生开放的花的唯一细胞型。这些结果表明，同域区是最好的特点是作为一个马赛克，而不是一个用餐，二倍体和四倍体在密切的接近和多倍体的分布是受生态排序在一个异质性的物理环境。
In North America. the geographic distributions of diploid and tetraploid Chamerion (formerly Epilobium) angustifolium overlap in a narrow zone along the southern border of the boreal forest and along the Rocky Mountains. We examined the frequency and distribution of diploid and tetraploid cytotypes in a narrow (5 km) zone of sympatry across an elevational gradient and in putatively uniform diploid and tetraploid reference populations on the Beartooth Pass, in the Rocky Mountains of southern Montana-northern Wyoming. All five reference populations sampled were dominated by a single cytotype, but only one was completely uniform. In the zone of sympatry, 27 transects were sampled every 2 m for a total of 238 plants. Reproductive status (vegetative, Bower buds, open flowers) was recorded, and the ploidy of each plant was determined by Bow cytometry. Diploid and tetraploid plants predominated (36 and 55%, respectively) but were heterogeneously distributed among the transects. Six of the 27 transects were fixed for a single cytotype (four transects, diploid; two transects, tetraploid), and in seven others either diploids or tetraploids predominated (frequency >75%). Triploids represented 9% of the total sample and occurred most frequently in transects containing both diploids and tetraploids (G = 3.4, df = 2, P = 0.07). Diploids were more often reproductive (in bud, Bower, or fruit) than either triploids or tetraploids (G = 12.0, df = 2, P < 0.001) and were the only cytotype to have produced open flowers. These results suggest that the zone of sympatry is best characterized as a mosaic rather than a dine, with diploid and tetraploids in close proximity and that the distribution of polyploidy is regulated by ecological sorting in a heterogeneous physical environment.