Morphological mechanism of growth response in treeline species Minjiang fir to elevated CO2 and temperature

Abstract

To test whether and how morphological traits are linked with growth responses of plants to temperature and CO 2 is important for understanding the mechanism underlying how plant growth will respond to global warming. In this study, using closed-top chambers to mimic future elevated CO 2 and temperature, the growth response, morphological traits of Minjiang fir (Abies faxoniana Rehd.et Wils.) and the relationship of the two were investigated after two years of exposure to the single and combined elevation of CO 2 and temperature. The results showed that biomass of Minjiang fir was 21%, 31%, and 35% greater than the control in elevated CO 2 , elevated temperature and the combination of elevated CO 2 and temperature treatments, respectively. Elevated CO 2 and temperature significantly affected the morphology of Minjiang fir, and a few morphological traits were highly correlated with growth responses. Larger branch angles at the upper layer, crown volume, and relative crown length contributed to positive growth responses to elevated CO 2 , while decreased specific leaf area (SLA) constricted any further growth response. Leaf morphological traits were more closely correlated with the response ratio than crown did in the elevated temperature, while in the combination of elevated CO 2 and temperature, crown was more correlated with the response ratio than the leaf morphological traits. Thus, our results indicate that morphological traits may contribute differently to growth responses under different experimental conditions.

Effects of experimental warming on growth, biomass allocation, and needle chemistry of Abies faxoniana in even-aged monospecific stands

“…In A. faxoniana seedlings, short-term warming increased height growth but had no effect on diameter (Hou et al 2011). Yet, these findings were obtained from experiments with young seedlings grown without competition.…”

“…A. faxoniana is widely distributed in those regions and it is particularly sensitive to warming (Wang 2004). There have been a few studies on morphological and physiological responses of single Picea asperata, Pinus tabulaeformis, and A. faxoniana seedling to short-term warming (about 5-12 months) in climate control growth chambers (Zhao and Liu 2009a, b;Hou et al 2011). Additional longterm experiments on the effects of warming are definitely needed.…”

Positive effects of night warming on physiology of coniferous trees in late growing season: Leaf and root

“…A few studies have focused on plant growth and physiological response of P. asperata and A. faxoniana seedlings to short-term continuous warming Zhao and Liu, 2009;Hou et al, 2011). However, long-term experiments to investigate the effects of artificial warming are definitely needed .…”

Climate constraints on growth and recruitment patterns of Abies faxoniana over altitudinal gradients in the Wanglang Natural Reserve, eastern Tibetan Plateau

“…Abies faxoniana is distributed over its entire altitudinal range in the Wanglang Natural Reserve, thereby allowing for an exploration of how fir growth and recruitment varies with elevation. Abies faxoniana has been considered an ideal tree species to explore the influence of global change, including responses to enhanced UV-B radiation (Liu et al 2011) and nitrogen supply (Yao and Liu 2009;Liu et al 2011), elevated atmospheric CO 2 concentration and elevated temperature (Hou et al 2010(Hou et al , 2011Wang et al 2012). However, our knowledge of the effects of long-term climate variability on A. faxoniana in these subalpine forests is limited.…”