细根(英語:fine root),是指植物根系中周转较快的那部分根,作为媒介传输土壤中的营养元素及水分至植物中[1]。细根周转(turnover)的过程中会释放大量的进入土壤中,形成大量的土壤有机质。土壤有机质受到环境的影响(气温、水分、肥料)会迅速释放大量的CO2,从而受到了广泛学者的关注。

北方森林(boreal forest)只占陆地土壤面积的15% 却拥有约33%的净初级生产力(NPP),对环境的变化最为敏感[2]。细根通常< 2mm,寿命远远小于粗根,从几个月到几年不等。为了准确估计细根寿命,目前研究通常用直径 < 1mm的细根[3]

研究方法主要有土钻法、内生长法/纱网法、微根管法(Minirhizotron)和同位素法,目前最准确的方法是微根管法,但每种方法仍有各自的利弊[1]。研究表明根系寿命和根系直径、土壤深度呈正相关,与土壤温度、肥性及含水量呈负相关[4]。不同树种的根系寿命也不同,通常落叶性树种与针叶树种相比具有更短的根系寿命[5]

參考資料

  1. ^ 1.0 1.1 Lukac, Martin. Fine Root Turnover. Mancuso, Stefano (编). Measuring Roots. Springer Berlin Heidelberg. 2012-01-01: 363–373 [2017-03-22]. ISBN 9783642220661. doi:10.1007/978-3-642-22067-8_18. (原始内容存档于2017-04-12) (英语). 
  2. ^ Persson, Hans Å. The distribution and productivity of fine roots in boreal forests. Atkinson, D. (编). Tree Root Systems and Their Mycorrhizas. Developments in Plant and Soil Sciences. Springer Netherlands. 1983-01-01: 87–101 [2017-03-22]. ISBN 9789400968356. doi:10.1007/978-94-009-6833-2_9#page-1. (原始内容存档于2018-06-12) (英语). 
  3. ^ Fine root biomass in relation to site and stand characteristics in Norway spruce and Scots pine stands (PDF). web.b.ebscohost.com. [2017-03-22]. (原始内容 (PDF)存档于2017-03-22) (英语). 
  4. ^ Leppälammi-Kujansuu, Jaana; Salemaa, Maija; Kleja, Dan Berggren; Linder, Sune; Helmisaari, Heljä-Sisko. Fine root turnover and litter production of Norway spruce in a long-term temperature and nutrient manipulation experiment. Plant and Soil. 2014-01-01, 374 (1-2): 73–88 [2017-03-22]. ISSN 0032-079X. doi:10.1007/s11104-013-1853-3. (原始内容存档于2018-06-10) (英语). 
  5. ^ Hansson, Karna; Helmisaari, Heljä-Sisko; Sah, Shambhu P.; Lange, Holger. Fine root production and turnover of tree and understorey vegetation in Scots pine, silver birch and Norway spruce stands in SW Sweden. Forest Ecology and Management. Influence of tree species on forest soils: New evidence from field studies. 2013-12-01, 309: 58–65. doi:10.1016/j.foreco.2013.01.022.