Data from: Towards a better understanding of the Chenopodium album aggregate (Amaranthaceae) in the Middle East: a karyological, cytometric and morphometric investigation

The study of variation in nuclear genome size, especially when combined with common garden experiments, significantly contributes to disentangling interspecies relationships within taxonomically complicated plant groups. The Chenopodium album aggregate is among the morphologically most variable groups and consists of many weakly differentiated cosmopolitan entities. We analysed nuclear genome size variation in diploid and polyploid species of the aggregate from Iran using flow cytometry of 282 accessions from 88 populations of 7 species. To this end, we also determined chromosome numbers and performed a morphometric study to reveal the extent of intraspecific morphological variation. We found that Iranian species are exclusively diploid (C. vulvaria), tetraploid (C. novopokrovskyanum, C. strictum, C. sosnowskyi and C. chaldoranicum) or hexaploid (C. album subsp. album, C. album subsp. iranicum and C. opulifolium). Six homogeneous relative genome size groups were distinguished among the species studied. Our morphometric study surprisingly revealed that under similar ecological conditions Chenopodium species are morphologically stable and well distinguishable, exhibited very little morphological variation. Hence, immense variation in leaf shapes, branching and inflorescence organization seen in the field has not been repeated under greenhouse conditions. The only exception was C. album s. str. which exhibited numerous morphotypes, covering the variation of remaining species.

核基因组大小变异的研究，尤其是结合同质园实验（common garden experiments）时，对厘清分类学疑难植物类群的种间关系具有重要意义。藜（Chenopodium album）复合群是形态变异最为显著的类群之一，包含多个分化程度较低的广布类群。本研究以伊朗境内该复合群的7个物种为研究对象，利用流式细胞术（flow cytometry）对其88个种群的282份种质材料开展核基因组大小变异分析。为此，本研究还测定了染色体数目，并开展形态计量研究以揭示种内形态变异的程度。研究发现，伊朗境内的该复合群物种仅包含二倍体（伏枝藜C. vulvaria）、四倍体（C. novopokrovskyanum、C. strictum、C. sosnowskyi与C. chaldoranicum）以及六倍体（C. album subsp. album、C. album subsp. iranicum与C. opulifolium）三类倍性。本研究在供试物种中共区分出6个均一的相对基因组大小类群。令人意外的是，本研究的形态计量结果显示，在相似生态条件下，藜属（Chenopodium）物种形态稳定且易于区分，种内形态变异极小。因此，野外观测到的叶形、分枝方式与花序结构的显著变异，在温室栽培条件下并未重现。唯一的例外是严格意义上的藜（C. album s. str.），其存在多种形态型，涵盖了其余所有供试物种的形态变异范围。