Did the First Angiosperms Lack an Embryo-Nourishing Endosperm? (An Accomplishment-Based Renewal)

首席研究员：William Edward Friedman建议编号：IOS-0919986建议标题：“最早的被子植物是否缺少滋养胚胎的胚乳？”该奖项由2009年美国复苏与再投资法案(公共法律111-5)资助。开花植物的起源代表了过去4.75亿年来植物进化中最重要的辐射之一。被子植物有超过25万个现存物种，是进化出的最大和最多样化的植物群体。长期以来，人们一直认为，第一次开花的植物形成了一种叫做胚乳的营养储存和胚胎营养组织，它来自于双受精过程中的第二次受精事件。事实上，许多进化生物学家已经提出，胚乳代表着与生态和进化成功有关的关键创新。以及开花植物的辐射。尽管研究很少，但有零星的证据表明，许多最古老的被子植物谱系并不依赖胚乳作为种子内的初级胚胎营养组织。该项目明确的目标是研究古代现存开花植物谱系的种子内的胚胎学过程，以重建第一批被子植物的胚胎营养行为模式。从该项目获得的比较发育数据有可能导致发现与开花植物的祖先向最早的被子植物过渡有关的“缺失环节”。在该项目的更广泛影响中，应该指出，全世界人类消耗的每三卡路里中就有两卡路里来自开花植物(例如水稻、玉米、大麦、小麦、椰子)的胚乳。因此，研究被子植物古代谱系的种子发育将提供基本的生物学信息，这些信息最终可能在应用和农业背景下相关。此外，这一项目要解决的问题非常基本，有理由期待调查结果将有助于国家和国际各级的本科生和研究生课程发展，就像过去的情况一样。可以预期，该项目的发现将广泛传播给公众。在上一轮资助周期中，研究成果在许多媒体上公布，包括哥伦比亚广播公司新闻、《今日美国》、《自然历史杂志》(特邀文章)、《新科学家》、《科学新闻》、《电讯报》(英国)以及来自世界各地的各种网站。最后，预计该项目将有助于科学人力资源的开发和提高科学界代表性不足群体成员的地位。弗里德曼实验室一直有很高比例的女性和代表性不足的群体成员，所有人都渴望在生命科学领域从事教育工作(实验室最近的两名成员后来在公立学校教授中学科学)和/或执业科学家(最近毕业的博士生是西班牙裔)。从本质上讲，虽然与该项目相关的绝大多数资金将用于支持解决基本和长期存在的科学问题，但这些资金也将是培养几名下一代生物学家和教师的核心。

Principal investigator: William Edward FriedmanProposal number: IOS-0919986Proposal title: "Did the First Angiosperms Lack an Embryo-Nourishing Endosperm?"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The origin of flowering plants represents one of the most significant evolutionary radiations of plants during the last 475 million years. With over 250,000 extant species, angiosperms are the largest and most diverse group of plants to have evolved. It has long been assumed that the first flowering plants formed a nutrient-storing and embryo-nourishing tissue called endosperm that is derived from a second fertilization event during the process of double fertilization. Indeed, many evolutionary biologists have suggested that endosperm represents a key innovation associated with the ecological and evolutionary ?success? and radiation of flowering plants. Although poorly studied, there is fragmentary evidence that many of the most ancient lineages of angiosperms do not rely upon an endosperm as the primary embryo-nourishing tissue within the seed. It is the explicit goal of the project to study the embryological processes within seeds of ancient extant lineages of flowering plants in order to reconstruct the pattern of embryo-nourishing behavior of the first angiosperms. The comparative developmental data to be derived from this project have the potential to lead to the discovery of a "missing link" associated with the transition from the ancestors of flowering plants to the earliest angiosperms. Among the broader impacts of this project, it should be noted that two out of every three calories consumed by humans worldwide are derived from the endosperm of flowering plants (e.g., rice, maize, barley, wheat, coconut). Thus, examination of seed development in ancient lineages of angiosperms will provide basic biological information that may ultimately be relevant in an applied and agricultural context. In addition, the questions to be addressed in this project are sufficiently basic to warrant the expectation that the findings will contribute to undergraduate and graduate curriculum development at the national and international levels, as has been the case in the past. Discoveries from this project can be expected to be widely disseminated to the general public. During the last grant cycle, research findings were publicized in a number of media outlets including CBS News, USA Today, Natural History Magazine (invited article), New Scientist, Science News, the Telegraph (U.K.), as well as a variety of websites from around the world. Finally, this project can be expected to contribute to the development of human resources in the sciences and the advancement of members of underrepresented groups in the sciences. The Friedman lab has consistently included a high proportion of women and members of underrepresented groups, all of who aspire to careers in the life sciences as educators (two recent members of the lab have gone on to teach secondary science in public schools) and/or practicing scientists (the most recent Ph.D. student to graduate is Hispanic). In essence, while the vast majority of funds associated with this project will go to support the solution of basic and longstanding scientific questions, these funds will also be central to the development of a few of the next generation of biologists and teachers.