植物生态学报 ›› 2017, Vol. 41 ›› Issue (11): 1208-1218.doi: 10.17521/cjpe.2017.0084

• 综述 • 上一篇    

挺水和湿生草本植物传输甲烷的过程与机制研究进展

窦渤凯1,2, 王义东1,*(), 薛冬梅1, 王中良1,2   

  1. 1天津师范大学天津市水资源与水环境重点实验室, 天津 300387
    2天津师范大学地理与环境科学学院, 天津 300387
  • 收稿日期:2017-03-31 接受日期:2017-11-14 出版日期:2017-11-10 发布日期:2017-11-10
  • 通讯作者: 王义东 E-mail:wangyidong@tjnu.edu.cn

Research advancement in the processes and mechanisms of transporting methane by emerged herbaceous plants and hygrophytes

Bo-Kai DOU1,2, Yi-Dong WANG1,*(), Dong-Mei XUE1, Zhong-Liang WANG1,2   

  1. 1Tianjin Key Laboratory of Water Resources and Environment, Tianjin Normal University, Tianjin 300387, China
    and
    2School of Geographic and Environmental Sciences, Tianjin Normal University, Tianjin 300387, China
  • Received:2017-03-31 Accepted:2017-11-14 Online:2017-11-10 Published:2017-11-10
  • Contact: Yi-Dong WANG E-mail:wangyidong@tjnu.edu.cn

摘要:

甲烷(CH4)是一种重要的温室气体, 参与大气光化学反应。水生与湿生环境是大气CH4的重要来源。挺水和湿生草本植物是CH4释放的重要通道, 研究植物如何传输CH4具有重要的意义。在植物传输CH4的过程中, 根系尤其是侧根根尖区起到了关键调控作用; 通气组织内部的隔膜与根茎连接部位也是调控CH4传输的重要界面。在早期的研究中, 关于茎叶排放CH4主要通过气孔还是微孔(位于地上部除叶片以外的细小的裂隙与孔洞)这一问题存有争议, 但是微孔的主导传输作用逐渐被后期的研究证实。枯死与损伤的茎干通常促进CH4传输排放。扩散与对流是植物传输CH4的两种主要机制, 对流的传输效率高于扩散。生物因素(生物量与光合作用等)与环境因子(光照与温、湿度等)共同调控着植物传输CH4。目前针对植物传输CH4的过程与机制已有较系统的认识, 但需要深入研究下列问题: (1)植物传输CH4的系列关键界面中, 各个界面的传输效率如何? 哪个界面对整体传输起决定性作用? (2)扩散与对流分别对各界面交换与整体长距离传输的内在调控作用。(3)各生物与非生物影响因子间的耦合作用机制。(4)物种间CH4传输机制与效率的异同。

关键词: 甲烷传输, 通气组织, 对流, 水生植物, 湿地植物, 温室气体

Abstract:
Methane (CH4) is an important greenhouse gas, and is involved in atmospheric chemical reactions. Aquatic and hydric environments are important sources of atmospheric CH4. Majority of CH4 are transported and released to atmosphere by emerged herbaceous plants and hygrophytes in aquatic and hydric environments. In recent decades, there has been increasing attention on how plants transport CH4. During CH4 transportation processes, several interfaces of CH4 exchange play important roles. First, the tips of lateral roots are primary locations (hotspots) for CH4 entering the root systems and regulate the gross CH4 transportation. Then, the diaphragms in the aerenchyma and the root collar impose great resistances for the overall CH4 transportation processes. In early studies, it was controversial that whether CH4 emission from plants to atmosphere was controlled by stomas or micropores (small cracks and holes in aboveground part of plant except the blade). Recent studies have confirmed the dominant role of micropores for CH4 transportation and emission. The dead and damaged stems are widely considered to have positive effects on CH4 transportation. Diffusion and convection are the two main transporting mechanisms of CH4, with the efficiency of convection being generally higher than that of diffusion. Both biological (e.g. biomass and photosynthesis) and environmental (e.g. light, temperature and humidity) factors regulate the CH4 transportation. Many studies have contributed to understanding the CH4 transportation processes and mechanisms by emerged herbaceous plants and hygrophytes. However, there are still some questions needing further investigations. Issues of consideration may include the operational efficiency in the critical interfaces of CH4 exchange, the plant parts that play a decisive role in the entire CH4 transportation, the underlying roles of diffusion and convection on CH4 interfaces exchanges and entire long distance transports, the combined and coupling effects and mechanisms of biotic and abiotic factors, and the similarities and differences of CH4 transporting processes and mechanisms among plant species.

Key words: Methane transportation, aerenchyma, convection, aquatic plants, wetland plants, greenhouse gases