“…It was reported that the substrates for plant growth respiration (R g ) (Amthor, 2000;Piao et al, 2010;Mahecha et al, 2010;Chapin et al, 2011) and rhizomicrobial respiration (R rhi ) Cheng, 2001, 2004;Dilkes et al, 2004;Heinemeyer et al, 2006Heinemeyer et al, , 2007Moyano et al, 2007Moyano et al, , 2008Gaumont-Guay et al, 2008;Kuzyakov and Gavrichkova, 2010;Mahecha et al, 2010) are both derived from current photosynthate, and their respiratory rates couple closely with GPP. During the process of plant photosynthesis, growth respiration (R g ) consumes some photosynthate to provide energy for satisfying growth demand.…”