Figure3. Biplot of environmental factors (soil water content and
electrical conductivity) with community characteristics and functional
trait variables by redundancy analysis (RDA). Hollow black arrows are
soil water content and electrical conductivity; solid blue arrows are
functional traits of P. australis . Abbreviations: EC, electrical
conductivity; SWC, soil water content; H, average height; Nu, number of
plants; SPAD, SPAD values; LWC, leaf water content; SLA, specific leaf
area; LA, leaf area; LT, leaf thickness; Lpnu, pitch number; Lpih;
internode height; and BSD, base stem diameter. Green indicates plant
traits including H and Nu; red indicates leaf traits including SPAD, LT,
LA, SLA, and LWC; black indicates stem traits including Lpih, Lph, Lpnu,
and BSD.
3.4 P. australis adaptability and plasticity
Environmental factors and selected functional traits of P.
australis varied greatly (Table 3), indicating the strong phenotypic
plasticity and environmental tolerance of P. australis . The
coefficient of variation of soil water content was larger than 25%,
while the electrical conductivity was up to 87%. The amplitude of soil
water content (9.39–36.92%) and electrical conductivity (0.14–13.29
ms/cm) indicated the high tolerance of P. australis to
environmental variables in the Yellow River Delta. The coefficients of
variation of leaf traits were lower than 20%, except for the leaf area,
while the stem traits were higher than 20%.
Table 3. Statistical characteristics of environmental variables
and functional traits for P. australis.