The effect of experimental warming on fine root functional traits of woody plants: Data synthesis

Contrasting depth‐related fine root plastic responses to soil warming in a subtropical Chinese fir plantation

“…Soil warming had no significant effect on total FRB (Figure 3c), which supported our second hypothesis. This result was consistent with the conclusion that the promoting effect of warming on FRB decreased with increasing temperature (Keuper et al, 2017;Wang et al, 2017Wang et al, , 2021Zhao et al, 2023). There might be two reasons for the lack of a warming effect on total FRB.…”

“…Decreased fine root P concentration and increased fine root N:P ratios under warming agree with some previous studies (Wang et al, 2021;Xiong et al, 2018;Zhao et al, 2023), suggesting that climate warming alters the relative supply of plant N and P (Yuan & Chen, 2015) and which would further aggravate P limitations. This might result from reduced soil P availability and weakened root P uptake capacity.…”

“…across different studies. For example, two recent meta-analyses both showed that the effect size of climate warming on FRB decreased with mean annual temperature (MAT) and was minor at low latitude (Wang et al, 2021;Zhao et al, 2023). Deeper rooting for water uptake from subsoil is also common under warming (Keuper et al, 2017;Wang et al, 2017), which was confirmed in the metaanalysis of Wang et al (2021) who found a stronger warming response of FRB in deeper soil layers.…”

“…Consequently, N can be more readily available at depth than P. N uptake and tissue N concentrations may then be less sensitive to surface soil dryness because there is a greater possibility for N to be taken up from subsoil (Salazar-Tortosa et al, 2018). Indeed, two recent meta-analyses have revealed that warming increased fine root N concentration but decreased fine root P concentration of terrestrial plants (Wang et al, 2021;Zhao et al, 2023). Some coordination in the acquisition of soil water and nutrients down the soil profile is expected if for plants are to cope with the vertical mismatch among these resources under global warming (Weemstra et al, 2016).…”

“…On that basis, we hypothesized that: (1) warming increases fine root N concentration but decreases fine root P concentration. Secondly, because a warming stimulation on FRB decreases with increasing mean annual temperature (approaching a minor effect at low latitude) and is more pronounced in deeper soil (Wang et al, 2021;Zhao et al, 2023), we hypothesized that: (2) soil warming will have a relatively minor effect on total FRB at our site (with a MAT of 19.1°C), but will result in deeper rooting to sustain water uptake from subsoil.…”