A natural hybrid of Impatiens, in the introduced range, demonstrated by sequence analysis of the nuclear ribosomal DNA-gene repeat

In a nature reserve, in Ticino canton in Switzerland amidst a mixed population of non-native <i>Impatiens parviflora</i> and <i>I. glandulifera</i> aberrant plants of <i>I. parviflora</i> were observed. A herbarium voucher and seeds were collected and seedlings subsequently raised in a greenhouse. Molecular analysis for ITS region and chloroplast markers revealed the plants to be a hybrid between <i>I. parviflora</i> and <i>I. balfourii</i>, another non-native <i>Impatiens</i> species occurring in the Ticino canton. No crossing out nor reduced fertility was observed in F2 and F3 generations, raised in a greenhouse. Sizeable populations of the hybrid have been observed in 2014 in the Ticino canton in the absence of the parental species. Nuclear genome size as measured by flow cytometry with propidium iodide did not indicate polyploidy and the ITS region remained 100% uniform. Therefore a homoploid hybrid speciation event is assumed.

在瑞士提契诺州的一处自然保护区内，于外来物种小花凤仙花（*Impatiens parviflora*）与腺毛凤仙花（*I. glandulifera*）的混合种群中，观测到了小花凤仙花的异常植株。研究人员采集了该植株的标本馆凭证标本与种子，随后在温室中培育得到实生苗。针对内转录间隔区（ITS）与叶绿体标记的分子分析结果显示，该异常植株为小花凤仙花与鲍尔凤仙花（*I. balfourii*）的杂交种，后者同样是分布于提契诺州的外来凤仙花属（*Impatiens*）物种。在温室培育的F2代与F3代杂交后代中，未观测到杂交衰退或育性降低现象。2014年，研究人员在提契诺州无亲本物种分布的区域内，观测到了该杂交种的可观种群规模。通过碘化丙啶（propidium iodide）标记的流式细胞术检测核基因组大小，结果未检测到多倍性特征，且ITS区域序列保持100%一致。因此推测该杂交种经历了同倍体杂交物种形成事件。