Department of Biology, Laurentian University 935 Ramsey Lake Road, Sudbury, Ontario, Canada, P3E-2C6 ; Biomolecular Science Program, Laurentian University 935 Ramsey Lake Road, Sudbury, Ontario, Canada, P3E-2C6.
Biomolecular Science Program, Laurentian University 935 Ramsey Lake Road, Sudbury, Ontario, Canada, P3E-2C6.
Ecol Evol. 2014 Sep;4(17):3435-43. doi: 10.1002/ece3.1195. Epub 2014 Aug 19.
White birch (Betula papyrifera) is an open pollinate species that is, dominant in the Northern Ontario after land reclamation. In fact, this species represents 65% of all trees in the region. We hypothesized that the exchange of genetic information between fragmented populations by range-wide paternal introgression is possible in wind-pollinated species such as B. papyrifera. On the other hand, the effects of heavy metal contamination from the mining activities on plant growth and population dynamics are well documented. The main objectives of this study were (1) to assess the level of genetic variation, gene flow, and population sustainability of B. papyrifera after land reclamation; and (2) to determine the level of phytoavailable metals in soil and their accumulation in trees. We found that B. papyrifera is a Ni and Zn accumulator with a translocation factor of 6.4 and 81, respectively, and an indicator of Cu and Pb. The level of polymorphic loci, Shannon index, Nei's genetic diversity, observed number of alleles, and gene flow were determined for the fragmented populations within the targeted region. The percent of polymorphic loci ranged from 28% to 56%; the gene flow was also low with a value of 0.89, and the population differentiation was very high with a value of 0.36. Two population-diagnostic ISSR markers were identified. They were cloned, sequenced, and converted to SCAR markers. Overall, the fragmented populations of B. papyrifera in Northern Ontario are genetically sustainable based on the moderate level of intrapopulation variability.
白桦（Betula papyrifera）是一种开放授粉的物种，在北方安大略省开垦土地后占据主导地位。事实上，该物种占该地区所有树木的 65%。我们假设，在风媒传粉物种如 B. papyrifera 中，通过广泛的父本渐渗，破碎种群之间遗传信息的交换是可能的。另一方面，采矿活动产生的重金属污染对植物生长和种群动态的影响已有充分的记录。本研究的主要目的是：（1）评估开垦土地后白桦的遗传变异水平、基因流和种群可持续性；（2）确定土壤中可利用金属的水平及其在树木中的积累。我们发现，白桦是 Ni 和 Zn 的积累者，其转移因子分别为 6.4 和 81，是 Cu 和 Pb 的指示剂。在目标区域内的破碎种群中确定了多态性位点、香农指数、Nei 的遗传多样性、观察到的等位基因数和基因流的水平。多态性位点的百分比范围为 28%至 56%；基因流也很低，值为 0.89，种群分化非常高，值为 0.36。鉴定出了两个种群诊断 ISSR 标记。它们被克隆、测序并转化为 SCAR 标记。总体而言，基于中等水平的种群内变异性，北方安大略省的白桦破碎种群在遗传上是可持续的。
