Photosynthesis acclimation, leaf nitrogen concentration, and growth of four tree species over 3 years in response to elevated carbon dioxide and nitrogen treatment in subtropical China

Long‐term nitrogen addition modifies microbial composition and functions for slow carbon cycling and increased sequestration in tropical forest soil

“…China has become the largest N creator and emitter globally (Liu, Zhang, Han, et al, ). Modeled predictions of N deposition are for 105 Tg N/year across Asia by 2030 (Mo et al, ; Zheng et al, ), and deposition rates of up to 73 kg N ha −1 year −1 have been already recorded in tropical old‐growth forests in southern China (Liu et al, ). While experimental data on the responses of temperate and boreal forests to elevated N deposition are relatively extensive, similar investigations in Chinese tropical forest ecosystems are sparse, and of a much shorter timescale, with the most well‐established starting in the 2000s (Liu et al, ).…”

The effects of rising atmospheric carbon dioxide on shoot-root nitrogen and water signaling

“…Leaf N concentration declines under prolonged growth at elevated CO 2 (Oren et al, 2001) unless plants are heavily fertilized with NH 4 NO 3 (Crous et al, 2010; Liu et al, 2011). This suggests that mechanisms for long distance root–shoot communication of root N availability and shoot N status, which evolved under low CO 2 , may lack plasticity to maintain root–shoot coordination under elevated CO 2 .…”

“…Photosynthetic acclimation can account for some of this decrease (Long et al, 2004), but fertilization with NH 4 NO 3 eliminates it (Crous et al, 2010; Liu et al, 2011), showing that increased N supply can compensate for the effects of elevated CO 2 through enhanced root N uptake and plant N assimilation. This suggests that elevated CO 2 interrupts shoot to root N signaling.…”

Impact of global climate change and fire on the occurrence and function of understorey legumes in forest ecosystems

“…Although a large amount of information has been published on the influence of global environmental changes on forest ecosystems (e.g., Sitch et al 2008;Allen et al 2010;Liu et al 2011a), most of it deals with the aboveground ecosystem components (Xu and Chen 2006;Liu et al 2011b). There is increasing evidence that aboveand belowground processes are intimately linked (Heimann and Reichstein 2008) and it is therefore critical to adopt a change of framework in order to unravel the impacts of environmental alterations on plant-soil-microbe interactions and ultimately on ecosystem functioning.…”

“…Because increased CO 2 did not occur in isolation but was accompanied by elevated N deposition and altered cycles of elements due to anthropogenic activities, the outcomes of global climate change are even more difficult to predict (Xu et al 2009;Owens and Xu 2011). Most studies conclude that elevated CO 2 concentration should increase photosynthesis by stimulating the carboxylation rate of Rubisco and reducing photorespiration (Schimel 1995;Atkin et al 1999), provided that available N and water are present in sufficient amounts (Liu et al 2010(Liu et al , 2011a. As shown in Table 1, greater stimulation of photosynthesis and growth of legumes and actinorhizal plants, compared to non-N 2 -fixers, is expected under elevated CO 2 concentration (Soussana and Hartwig 1996;Zanetti et al 1996;Rogers et al 2006;Tobita et al 2010).…”