PRF: Multiply-sired Fruits in Field Populations of Lesquerella fendler: Occurence and Mechanisms

PRF：香茅田间繁殖果实：发生和机制

• 批准号: 9203203
• 负责人: Randall Mitchell
• 金额: $ 6.96万
• 依托单位: Individual Award
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-07-01 至 1994-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9203203&HistoricalAwards=false
• 关键词: PRF; Multiply; sired; Fruits; Field

While the potential for sexual selection as an important factor in plant evolution is now becoming recognized, there is surprisingly little direct knowledge about how often conditions required for its actions occur. One indication of the opportunity for sexual selection in plants is the occurrence of multiply sired fruits. Such fruits are unambiguous evidence that pollen from more than one mate was available to fertilize seeds, and therefore indicate that female choice of male competition (forms of sexual selection) may act. However, there is detailed knowledge about the frequency of multiply sired fruits for only a single, introduced species. The P.I. will study the occurrence of and mechanisms causing multiply sired fruits for a native plant of South Western deserts, Lesquerella fendleri. To determine frequency, the P.I. will ascertain paternity for seeds from plants in 3 separate populations at the Sevilleta Long-Term Ecological Research Site. Preliminary studies indicate that Lesquerella fruits are commonly multiply sired. To determine the mechanisms causing multiply sired fruits two approaches will be taken. First, paternity resulting from single and multiple pollinator visits in nature will be compared. Second, observed pollinator visitation rates will be used to construct a realistic schedule of hand pollinations to investigate the effects of single and multiple visits under more controlled conditions. Knowledge of the responsible mechanisms will not only help to predict which species are likely to produce multiply sired fruits, but can help delimit their possible evolutionary consequences.

虽然性选择作为植物进化中的一个重要因素的潜力现在已经被认识到，但令人惊讶的是，关于其行为发生所需条件的直接知识很少。在植物中有性选择的机会的一个迹象是出现多个后代。这样的果实是明确的证据，证明来自不止一个配偶的花粉可用于使种子受精，因此表明雌性选择雄性竞争（性选择的形式）可能起作用。然而，只有一种引进的物种才会有多次繁殖的频率。P.I.将研究西南沙漠本地植物Lesquerella fendleri多子代果的发生和机制。为了确定频率，P.I.将确定来自塞维利亚塔长期生态研究基地3个不同种群的植物种子的父系关系。初步研究表明，Lesquerella果实通常是多子代的。为了确定产生多子代的机理，将采取两种方法。首先，将比较自然界中单次和多次传粉者访问所产生的父系关系。其次，利用观察到的传粉者访花率来构建一个现实的手传粉时间表，以研究在更可控的条件下单次和多次访花的效果。对相关机制的了解不仅有助于预测哪些物种可能产生多胞胎，还有助于确定它们可能产生的进化后果。