Analysis of Eco-physiological Strategies of Fern Species Based on Leaf Traits

Abstract:

To clarify the adaptability of ferns to environmental changes, thirty typical terrestrial fern species were selected from tropical and subtropical regions, measured their leaf (pinna) morphological structure, mechanical resistance and water relationship traits, and used the corresponding traits of 54 woody angiosperms in the same region as a reference. Combined with phylogenetic and trait network analysis, the correlations of leaf traits in ferns were analyzed. The results showed that compared with woody angiosperms, ferns had lower puncture force (F_p), weaker embolism resistance (P50_leaf), and higher turgor loss point (Ψ_tlp), indicating that ferns had lower resistance to mechanical damage and water stress. The saturated water content (SWC) of fern leaves was significantly positively correlated with Ψ_tlp and P50_leaf, suggesting that ferns balanced their relatively weak drought tolerance by increasing leaf water storage capacity; the SWC of angiosperm leaves was not correlated with P50_leaf. The F_p of angiosperm leaves was significantly positively correlated with leaf mass per area, leaf thickness and maximum leaf hydraulic conductance; the F_p of ferns was only significantly positively correlated with leaf thickness, and the two evolved in concert. Therefore, different plant groups have diverse strategies for adapting to the environment.