Differences in Fine Root Traits of <i>Quercus rehderiana</i> Between Rocky and Nonrock Desertification Forests in Southwest China

Fine roots (diameter < 2 mm) play a crucial role in plants' acquisition of soil water and nutrients. Their morphological and chemical traits, which reflect resource utilization strategies, have garnered significant global research attention. However, the extent to which these traits are influenced by environmental conditions remains unclear. In this study, we measured 14 morphological and chemical traits from nine <i>Quercus rehderiana</i> individuals in both rocky and nonrocky desertification forest habitats. Our objectives were to identify the key factors shaping fine root traits and elucidate their adaptive strategies in the arid, nutrient-poor conditions of rocky desertification forest ecosystems. The results revealed that <i>Quercus rehderiana</i> fine roots in rocky desertification forests exhibited higher root length (RL), root volume (RV), nitrogen (N), calcium (Ca), and magnesium (Mg) concentrations, along with an elevated nitrogen-to-phosphorus ratio (N:P ratio), compared to those in nonrocky desertification forests. Conversely, fine roots in nonrocky desertification forests showed greater phosphorus (P) and potassium (K) concentrations. Correlation analysis indicated that in rocky desertification forests, specific root length (SRL) and specific root area (SRA) were positively correlated with root P concentration, while root N concentration exhibited synergistic relationships with P and K. In contrast, nonrocky desertification forests displayed trade-offs: SRL and SRA were negatively correlated with RV, root diameter (RD), and root tissue density (RTD), and root carbon (C) concentration was inversely related to Ca and Mg. Principal component analysis further demonstrated that rocky desertification forests favored a resource-acquisition strategy, characterized by enhanced morphological traits and nutrient concentrations, whereas nonrocky desertification forests leaned toward a resource-conserving strategy, prioritizing P and K accumulation. These findings highlight that <i>Quercus rehderiana</i> adapts to divergent environments through distinct resource allocation mechanisms, with its unique traits in rocky desertification forests underscoring its suitability for ecological restoration efforts.