DISSERTATION RESEARCH: Polyploidy and Reproductive Isolation in the North American Creosote Bush (Larrea tridentata, Zygophyllaceae)

论文研究：北美杂酚油灌木（Larrea tridentata，Zygophyllaceae）的多倍体和生殖隔离

• 批准号: 1010738
• 负责人: Justin Ramsey
• 金额: $ 1.48万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1010738&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Polyploidy; Reproductive; Isolation

Many plant species have both diploid individuals (possessing two sets of chromosomes) and polyploid individuals (possessing four or more sets). Related diploid and polyploid plants are rarely named as different species, in part due to uncertainty about their potential for interbreeding in nature. Creosote bush, a dominant shrub of North American warm deserts, has both diploid and polyploid populations. The PIs will evaluate the ability of these populations to interbreed. Creosote bushes are excellent for such studies because the diploid and polyploid populations come in contact at many different locations, thus allowing replicated studies of the level of interbreeding. The PIs will use field studies and molecular laboratory techniques to evaluate the following possible influences on interbreeding: a) the tendency of diploids and polyploids to occur in different environments, b) the tendency of diploids and polyploids to reproduce at different times of the year, and c) the reproductive success of naturally-occurring triploid and pentaploid hybrids. The multiplicative effects of these reproductive barriers will be calculated. If the barriers to interbreeding are strong, a case can be made for diploids and polyploids being distinct species.If there is strong evidence that diploid and polyploid populations are unable to interbreed, the many other species that have both diploids and polyploids will need to be re-evaluated; these results could potentially lead to a conclusion that plant species diversity in temperate regions is far greater than currently believed. Undergraduates will be involved in all parts of the proposed research in the field and laboratory. The PIs expect to give two undergraduates the opportunity to complete senior theses based on their involvement in the research.

许多植物既有二倍体个体(拥有两组染色体)，也有多倍体个体(拥有四组或更多组染色体)。相关的二倍体和多倍体植物很少被命名为不同的物种，部分原因是它们在自然界中杂交的潜力不确定。杂色灌木是北美温暖沙漠的一种优势灌木，有二倍体和多倍体种群。PI将评估这些种群的杂交能力。杂酚油灌木丛非常适合这类研究，因为二倍体和多倍体种群在许多不同的地点接触，从而允许对杂交水平的重复研究。PIS将利用实地研究和分子实验室技术来评估以下可能对杂交的影响：a)二倍体和多倍体在不同环境中出现的趋势，b)二倍体和多倍体在一年中的不同时间繁殖的趋势，以及c)自然发生的三倍体和五倍体杂种的繁殖成功。这些生殖障碍的乘法效应将被计算出来。如果杂交的障碍很大，就有理由认为二倍体和多倍体是不同的物种。如果有强有力的证据表明二倍体和多倍体种群无法进行杂交，那么许多同时具有二倍体和多倍体的其他物种将需要重新评估；这些结果可能会导致一个结论，即温带地区的植物物种多样性远远大于目前认为的。本科生将参与拟议中的实地和实验室研究的所有部分。PIS预计将给两名本科生根据他们参与研究的情况完成高级论文的机会。