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Scientia Silvae Sinicae ›› 2016, Vol. 52 ›› Issue (4): 100-109.doi: 10.11707/j.1001-7488.20160412

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Interaction of Litter Decomposition and Fine-Root Growth

Wang Wei1,2, Hu Kai2, Dang Chengqiang1, Tao Jianping1   

  1. 1. Key Laboratory of Eco-Environments in Three Gorges Reservoir Region(Ministry of Education) Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region School of Life Science, Southwest University Chongqing 400715;
    2. College of Forestry and Life Science, Chongqing University of Arts and Sciences Chongqing 402168
  • Received:2015-03-21 Revised:2016-02-25 Online:2016-04-25 Published:2016-05-05

Abstract: In different forest ecosystems, fine roots commonly proliferate into litter layers, especially into those with favorable conditions for root growth. Our aim is to provide a basis for better understanding the role and mechanism of action in litter decomposition by fine roots and the influence of litter decomposition on fine root growth.We reviewed the advances of recent studies, including how roots forage into litter, the factors influencing this foraging, and the influence and possible mechanisms of fine root growth on litter decomposition. We put forward a conceptual module that enhances understanding of the interaction between fine-root growth and litter decomposition.Litter quantity on the soil surface affects the foraging behavior of fine-roots and drives their growth dynamics. Litter quality can also affect fine-root growth. Fine-root growth enhancement or inhibition could be the result of a positive or negative balance between nutrient and polyphenols concentrations generated during the decomposition of litter with different properties. By proliferating in litter, fine roots potentially influence litter decomposition through priming effects, N uptake, and symbiotic mycorrhizal fungi. The priming effects of live fine-roots on litter decomposition are mainly manifested by root exudate C inputs, which can regulate decomposition of litter by controlling the activity and composition of the microbial community. Nitrogen availability is critically important to litter decomposition, and low N availability can increase decomposition as microbes use labile substrates to acquire N from recalcitrant organic matter. Fine-roots grow into a decomposed litter layer, which avoid the adverse effects of excess N on microorganisms by absorbing a large amount of inorganic N during litter mineralization. In addition, root symbiotic partners, i.e., mycorrhizal fungi, have an important impact on litter decomposition through the types of fungi and enzymes and organic acids secretion.Key scientific issues for future research include the mechanism of combined effect of fine root growth on litter decomposition in the context of global climate change, as well as the connection of the fine root branching structure and function of nutrient acquisition in the litter layer.

Key words: litter, decomposition, fine root growth, root foraging, mycorrhizal fungi, underground processes

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