Ecophysiological responses of two dominant subalpine tree species Betula albo-sinensis and Abies faxoniana to intra- and interspecific competition under elevated temperature

Species-specific competition and N fertilization regulate non-structural carbohydrate contents in two Larix species

“…N fertilization significantly enhanced leaf d 13 C under inter-and intraspecific competition (Fig. 3b), which indicated a higher water use efficiency in a long term (Farquhar et al, 1982;Duan et al, 2014;Dong et al, 2015) and the sink regulation of photosynthesis changes. Changes in the photosynthetic parameters of leaves caused by competition or N fertilization would influence the carbon supply and probably C allocation.…”

“…Neighbors can affect N absorption ability or N form (ammonium vs nitrate). Duan et al (2014) found that A. faxoniana exhibits a better performance when competing with Betula albosinensis compared with intraspecific competition under elevated temperature; also the soluble sugar concentration of roots increased. In our study, interspecific competition showed positive impacts on the leaf N concentration and negative influences on the leaf C:N ratio, while the latter parameter was primarily driven by the former one because of the relative constant C concentration (Fig.…”

“…Previous studies have confirmed that inter-or intraspecific competition may lead to substantial changes in photosynthetic capacity , nitrogen absorption (Miller et al, 2007;Ashton et al, 2008;Duan et al, 2014) and root exudates (reviewed by Schenk, 2006;Pierik et al, 2013), which enable the optimization of plants' performance in varied environments. Duan et al (2014) observed that Abies faxoniana changes its nitrogen uptake and has a better performance under interspecific competition with Betula albo-sinensis compared with monocultures under elevated temperature. Respectively, Liu et al (2004) discovered that European beech (Fagus sylvatica) has high sensitivity to elevated CO 2 and O 3 when in monoculture but that largely disappears under interspecific competition with Norway spruce (Picea abies).…”

“…The starch concentration has been found to increase under stressful conditions and decline in favorable environments (Zhang et al, 2008;Duan et al, 2014). C remobilization from a stored C pool has been demonstrated to be an important process during bud burst (Maurel et al, 2004) and root formation (Maillard et al, 2001).…”

Long-term responses of plant growth, soil microbial communities and soil enzyme activities to elevated CO2 and neighbouring plants

“…In subalpine regions, climate change may alter plant growth and plant litter quality, and these alterations may subsequently affect microbial biomass, community structure, and soil microbial activities. In a recent study, we showed that tree neighbours affect the growth and sensitivity of A. faxoniana to climate change (Duan et al, 2014). Further investigations into the role of neighbours in determining plant growth under elevated CO 2 via microbial responses are needed to improve the current understanding of the effects of climate change on long-term C and N storage and the productivity of the subalpine conifer ecosystem in the Qinghai-Tibet Plateau of China.…”