Phragmites australis is the dominant species in the Yellow River Delta
and plays an important role in wetland ecosystems. Ecological responses
of the P. australis community to soil properties were investigated in 96
areas along the coastal-inland regions in the Yellow River Delta of
China. The aim was to evaluate the relationship between phenotypic
variation and environmental factors, reveal which functional traits
could well respond to changes in electrical conductivity and soil water
content, and the ecological strategies of P. australis. Within the range
of soil water content (9.39–36.92%) and electrical conductivity
(0.14–13.29 ms/cm), the results showed that the effects of soil water
content and salinity were not equally important for the characterization
of the morphological and physiological variability, and that plant
functional traits including leaf traits and stem traits responded more
strongly to soil salinity than soil water content. Our results suggested
that salinity leads to reduced average height, specific leaf area, leaf
area, and base stem diameter, but increased leaf water content and leaf
thickness. The relationships between functional traits and electrical
conductivity were generally linear and logarithmic. The coefficients of
variation of morphological traits showed more phenotypic plasticity than
the physiological traits. Salinity also led to the stress
tolerator/competitor-stress tolerator (S/CS) strategies of P. australis;
with the decrease of environmental stress, the main strategy gradually
moved to the competitor (C) strategy, making P. australis the dominant
species in the Yellow River Delta. KEYWORDS: Soil water content,
Electrical conductivity, Functional traits, Plasticity, Life strategies.
Effects of Soil Water Gradient on Stress-resistant Enzyme Activities in Phragmites australis from Yellow River Delta