Damian Vaz de Sousa, Michelle Greve, Kenneth C. Oberlander
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Rich. across Gauteng, South Africa, and test for evidence of possible mechanisms, including morphological, phenological, and reproductive traits, that may potentially facilitate polyploid persistence.</p>\n </section>\n \n <section>\n \n <h3> Methods</h3>\n \n <p>Over 320 <i>O. obliquifolia</i> plants from 25 sites were cytotyped using flow cytometry, and DNA ploidy was confirmed using meiotic chromosome squashes. Cytotypes were mapped and correlations with abiotic variables assessed using ordinations. To assess morphological and phenological associations with cytotype, we grew multiple cytotypes in a common garden, measured phenotypic traits and compared them using linear models and discriminant analyses. Intercytotype reproductive isolation was assessed using crossing experiments, and AMOVAs based on ITS DNA sequences tested for cytogeographic structure.</p>\n </section>\n \n <section>\n \n <h3> Results</h3>\n \n <p>Six cytotypes were identified, and most sites had multiple cytotypes. Abiotic variables were not predictive of cytotype distribution. A clear gigas effect was present. Differences in flower size and phenology suggested pollinator interactions could play a role in polyploid persistence. Intercytotype crosses produced seed at low frequency. DNA data suggested diploids and polyploids were largely reproductively isolated in situ, and polyploidization events were not frequent enough to explain high cytotype sympatry.</p>\n </section>\n \n <section>\n \n <h3> Conclusions</h3>\n \n <p>Diploids and polyploids are behaving as separate species, despite little observable niche differentiation and non-zero potential intercytotype seed set. Tests on biotic interactions and intercytotype F1 fitness may provide insights into diploid and polyploid coexistence.</p>\n </section>\n </div>","PeriodicalId":7691,"journal":{"name":"American Journal of Botany","volume":null,"pages":null},"PeriodicalIF":2.4000,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ajb2.16291","citationCount":"0","resultStr":"{\"title\":\"Friends without benefits: Extensive cytotype sympatry and polyploid persistence in an African geophyte\",\"authors\":\"Damian Vaz de Sousa, Michelle Greve, Kenneth C. Oberlander\",\"doi\":\"10.1002/ajb2.16291\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div>\\n \\n \\n <section>\\n \\n <h3> Premise</h3>\\n \\n <p>Polyploidy is a major factor in plant adaptation and speciation. Multiple mechanisms contribute to autopolyploid frequency within populations, but uncertainties remain regarding mechanisms that facilitate polyploid establishment and persistence. Here we aimed to document and predict cytotype distributions of <i>Oxalis obliquifolia</i> Steud. ex A. Rich. across Gauteng, South Africa, and test for evidence of possible mechanisms, including morphological, phenological, and reproductive traits, that may potentially facilitate polyploid persistence.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Methods</h3>\\n \\n <p>Over 320 <i>O. obliquifolia</i> plants from 25 sites were cytotyped using flow cytometry, and DNA ploidy was confirmed using meiotic chromosome squashes. Cytotypes were mapped and correlations with abiotic variables assessed using ordinations. To assess morphological and phenological associations with cytotype, we grew multiple cytotypes in a common garden, measured phenotypic traits and compared them using linear models and discriminant analyses. Intercytotype reproductive isolation was assessed using crossing experiments, and AMOVAs based on ITS DNA sequences tested for cytogeographic structure.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Results</h3>\\n \\n <p>Six cytotypes were identified, and most sites had multiple cytotypes. Abiotic variables were not predictive of cytotype distribution. A clear gigas effect was present. Differences in flower size and phenology suggested pollinator interactions could play a role in polyploid persistence. Intercytotype crosses produced seed at low frequency. DNA data suggested diploids and polyploids were largely reproductively isolated in situ, and polyploidization events were not frequent enough to explain high cytotype sympatry.</p>\\n </section>\\n \\n <section>\\n \\n <h3> Conclusions</h3>\\n \\n <p>Diploids and polyploids are behaving as separate species, despite little observable niche differentiation and non-zero potential intercytotype seed set. 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引用次数: 0
摘要
前提:多倍体是植物适应和物种形成的一个主要因素。多种机制导致了种群内的自多倍体频率,但促进多倍体建立和持续存在的机制仍存在不确定性。在此,我们旨在记录和预测南澳大利亚豪登省 Oxalis obliquifolia Steud.Rich.在南非豪登省的分布情况,并检验可能促进多倍体持续存在的机制证据,包括形态、物候和繁殖特征:方法:使用流式细胞仪对 25 个地点的 320 多株 O. obliquifolia 植物进行细胞分型,并使用减数分裂染色体压扁法确认 DNA 倍性。绘制了细胞型图,并使用排序法评估了细胞型与非生物变量的相关性。为了评估形态和表型与细胞型的关联,我们在一个共同的花园中种植了多个细胞型,测量了表型性状,并使用线性模型和判别分析对它们进行了比较。利用杂交实验评估了细胞型间的生殖隔离,并利用基于 ITS DNA 序列的 AMOVAs 检验了细胞地理结构:结果:确定了六个细胞型,大多数地点有多个细胞型。非生物变量不能预测细胞型的分布。存在明显的千兆效应。花朵大小和表型的差异表明,授粉者之间的相互作用可能在多倍体的持续存在中发挥作用。细胞型间杂交产生种子的频率较低。DNA 数据表明,二倍体和多倍体在很大程度上是就地繁殖隔离的,多倍体化事件并不频繁,不足以解释高细胞型共生现象:结论:二倍体和多倍体表现为不同的物种,尽管几乎观察不到生态位分化和潜在的细胞型间种子集落。对生物相互作用和细胞型间 F1 适宜性的测试可为二倍体和多倍体的共存提供启示。
Friends without benefits: Extensive cytotype sympatry and polyploid persistence in an African geophyte
Premise
Polyploidy is a major factor in plant adaptation and speciation. Multiple mechanisms contribute to autopolyploid frequency within populations, but uncertainties remain regarding mechanisms that facilitate polyploid establishment and persistence. Here we aimed to document and predict cytotype distributions of Oxalis obliquifolia Steud. ex A. Rich. across Gauteng, South Africa, and test for evidence of possible mechanisms, including morphological, phenological, and reproductive traits, that may potentially facilitate polyploid persistence.
Methods
Over 320 O. obliquifolia plants from 25 sites were cytotyped using flow cytometry, and DNA ploidy was confirmed using meiotic chromosome squashes. Cytotypes were mapped and correlations with abiotic variables assessed using ordinations. To assess morphological and phenological associations with cytotype, we grew multiple cytotypes in a common garden, measured phenotypic traits and compared them using linear models and discriminant analyses. Intercytotype reproductive isolation was assessed using crossing experiments, and AMOVAs based on ITS DNA sequences tested for cytogeographic structure.
Results
Six cytotypes were identified, and most sites had multiple cytotypes. Abiotic variables were not predictive of cytotype distribution. A clear gigas effect was present. Differences in flower size and phenology suggested pollinator interactions could play a role in polyploid persistence. Intercytotype crosses produced seed at low frequency. DNA data suggested diploids and polyploids were largely reproductively isolated in situ, and polyploidization events were not frequent enough to explain high cytotype sympatry.
Conclusions
Diploids and polyploids are behaving as separate species, despite little observable niche differentiation and non-zero potential intercytotype seed set. Tests on biotic interactions and intercytotype F1 fitness may provide insights into diploid and polyploid coexistence.
期刊介绍:
The American Journal of Botany (AJB), the flagship journal of the Botanical Society of America (BSA), publishes peer-reviewed, innovative, significant research of interest to a wide audience of plant scientists in all areas of plant biology (structure, function, development, diversity, genetics, evolution, systematics), all levels of organization (molecular to ecosystem), and all plant groups and allied organisms (cyanobacteria, algae, fungi, and lichens). AJB requires authors to frame their research questions and discuss their results in terms of major questions of plant biology. In general, papers that are too narrowly focused, purely descriptive, natural history, broad surveys, or that contain only preliminary data will not be considered.