RUI: Water In, Air Out: Mechanisms of Xylem Embolism Repair in Seed Plants

RUI：水进、气出：种子植物木质部栓塞修复机制

• 批准号: 1146993
• 负责人: Jochen Schenk
• 金额: $ 80万
• 依托单位: CSU Fullerton Auxiliary Services Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1146993&HistoricalAwards=false
• 关键词: RUI; Water; Air; Out; Mechanisms

Vascular plants transport water from roots to leaves in a highly specialized hydraulic system, the xylem. Most of the time, water in this system is under sub-atmospheric or negative pressure, which creates the possibility that air can be sucked into the conducting cells through leaks, forming air bubbles. These air bubbles, which are called xylem embolisms, can impede water transport in plants, in severe cases leading to death of roots, branches, or whole plants. In many plants, embolisms form even under mild drought stress, frequently even daily. Many plant species have been found to have the ability to remove air bubbles from the xylem and refill the conducting cells with water even while the xylem is still transporting water under negative pressure. Other species appear to be unable to repair embolism under negative pressure. The aims of this project are to test for embolism repair in seed plant species ranging from a grass to conifer trees, relate the findings to anatomical traits of the xylem, and test for cellular mechanisms used by these species to remove air and refill the hydraulic system. The research is designed to test alternative hypotheses regarding the refilling of water-conducting cells, which could involve either passive, physical processes or active, osmotic forces exerted by living cells that are associated with water-conducting cells. Several of the plant species studied are economically important crop, horticultural, and timber species, therefore insights into mechanisms of embolism repair will lead to a better understanding of drought tolerance in these plants and will have potential implications for agriculture, horticulture, and forestry, most directly for sustainable irrigation management practices. The project will continue ongoing and active involvement of undergraduate and graduate students in research, including a large number of students from underrepresented groups. The research will be done in an international collaboration with research labs in Belgium and Germany and will include international student and staff exchanges, which will expose students and researchers in all three collaborating labs to new ideas and experiences.

维管植物通过一个高度专业化的水力系统，即木质部，将水分从根输送到叶。大多数情况下，该系统中的水处于负压或负压下，这使得空气可能通过泄漏被吸入导电单元，形成气泡。这些被称为木质部栓塞的气泡会阻碍植物中的水分运输，严重时会导致根、枝或整株植物死亡。 在许多植物中，即使在轻度干旱胁迫下也会形成栓塞，甚至每天都有。 已经发现许多植物物种具有从木质部中去除气泡并用水重新填充传导细胞的能力，即使木质部在负压下仍然运输水。其他物种似乎无法在负压下修复栓塞。 该项目的目的是测试栓塞修复种子植物物种，从草到针叶树，将结果与木质部的解剖特征相关联，并测试这些物种用于去除空气和重新填充液压系统的细胞机制。该研究旨在测试有关水传导细胞再填充的替代假设，这可能涉及被动的物理过程或与水传导细胞相关的活细胞施加的主动渗透力。研究的几种植物物种是经济上重要的作物，园艺和木材物种，因此深入了解栓塞修复机制将导致更好地了解这些植物的耐旱性，并将对农业，园艺和林业产生潜在的影响，最直接的可持续灌溉管理实践。该项目将继续让本科生和研究生积极参与研究，包括来自代表性不足群体的大量学生。这项研究将与比利时和德国的研究实验室进行国际合作，并将包括国际学生和工作人员交流，这将使所有三个合作实验室的学生和研究人员接触到新的想法和经验。

项目成果

Effects of thermal gradients in sapwood on stem psychrometry

边材温度梯度对茎湿度的影响

• DOI: 10.17660/actahortic.2018.1197.4
• 发表时间: 2018
• 期刊: Acta Horticulturae
• 作者: Quick, D.D.;Espino, S.;Morua, M.G.;Schenk, H.J.
• 通讯作者: Schenk, H.J.

The stability enigma of hydraulic vulnerability curves: addressing the link between hydraulic conductivity and drought-induced embolism

• DOI: 10.1093/treephys/tpz078
• 发表时间: 2019-10-01
• 期刊: TREE PHYSIOLOGY
• 影响因子: 4
• 作者: De Baerdemaeker, Niels J. F.;Arachchige, Keerthika Nirmani Ranathunga;Steppe, Kathy
• 通讯作者: Steppe, Kathy