College of Resources and Environment Science, Xinjiang University, Urumqi, China.
Xinjiang Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China.
PLoS One. 2021 Feb 17;16(2):e0246672. doi: 10.1371/journal.pone.0246672. eCollection 2021.
Trait-based approaches have been used to demonstrate the responses of plant functional traits to environmental change may manifest both among- and/or within-species. However, how community-level foliar stoichiometric characteristic variations respond to aridity and salinity is still not well-known.
We calculated community weighted means (CWMs) and non-weighted means (CMs) of foliar C, N, and P concentrations (and their ratios) in a dryland plant community respond to high (HSW) and low soil moisture and salinity (LSW). Based on a sum of squares decomposition method, we determined the relative contributions of intraspecific variation and species turnover in both HSW and LSW habitats.
The CWMs of foliar C, C:N and C:P, and CM of N in the HSW habitat were significantly greater than those in the LSW habitat. The trait variations in two habitats were mainly driven by intraspecific variation, and its contribution to trait variation mostly declined with the decrease of soil moisture and salinity. The CWMs of foliar C-related stoichiometric characteristics were mainly dominated by species turnover in both habitats. Moreover, the contribution of species turnover to C and C:P variations showed an increasing trend in the LSW habitat. For CWMs, negative covariations between intraspecific variation and turnover occurred in HSW and positive covariations (except N:P) occurred in LSW; however, CMs were generally positively correlated in both habitats.
The intraspecific variation declined as drought stress intensified, which indicates that the adaptability of desert plants declined when the stress changed from salinity to aridity. The total variation of C-related traits in both habitats were mainly dominated by species turnover. These findings highlight the importance of intraspecific variation in driving desert plant response of community functional composition to salt stress, and the joint role of intraspecific variation and species turnover in resisting drought stress.
基于性状的方法已经被用于证明植物功能性状对环境变化的响应可能在种间和/或种内表现出来。然而，群落水平叶片化学计量特征的变化如何响应干旱和盐度仍然知之甚少。
我们计算了旱地植物群落叶片碳、氮和磷浓度（及其比值）的群落加权平均值（CWMs）和非加权平均值（CMs）对高（HSW）和低土壤水分和盐分（LSW）的响应。基于平方和分解方法，我们确定了种内变异和物种周转率在 HSW 和 LSW 生境中的相对贡献。
HSW 生境中叶片 C、C:N 和 C:P 的 CWMs 以及 N 的 CM 显著大于 LSW 生境。两个生境中的性状变化主要由种内变异驱动，其对性状变化的贡献随着土壤水分和盐分的降低而下降。两个生境中叶片 C 相关化学计量特征的 CWMs 主要由物种周转率主导。此外，物种周转率对 C 和 C:P 变化的贡献在 LSW 生境中呈增加趋势。对于 CWMs，HSW 中种内变异与周转率之间呈负相关，LSW 中呈正相关（除 N:P 外）；然而，CMs 在两个生境中通常呈正相关。
随着干旱胁迫的加剧，种内变异减少，这表明当胁迫从盐度变为干旱时，沙漠植物的适应性下降。两个生境中 C 相关性状的总变异主要由物种周转率主导。这些发现强调了种内变异在驱动荒漠植物对盐胁迫的群落功能组成的响应中的重要性，以及种内变异和物种周转率在抵抗干旱胁迫中的共同作用。
