4.4 Summarizes and Perspectives
Gradients of environmental stress and disturbance are important drivers of morphological and physiological variability for P. australisin the Yellow River Delta. The response of functional traits to the environment could be summarized as follows: (1) The relationships between functional traits and electrical conductivity were generally linear and logarithmic, indicating that soil salinity was the main factor that influenced the functional traits of P. australis in the Yellow River Delta. (2) The plant morphological traits had higher plasticity based on the coefficients of variation, which were much higher than 20%. However, compared with the morphological traits, the coefficients of variation for physiological leaf traits were lower than 20%. This indicated that physiological traits are more stable than morphological traits in response to environmental variables. (3) The variability of strategies for P. australis indicated that in the high-salinity area, competition (C) and stress tolerator (CS) were the main strategies that affected the growth and distribution for P. australis. With the decrease of environmental stress, the mainly strategy gradually moved from S to C. Further studies, including studies focused on underground traits and genetics, are needed to clearly understand different responses to related ecotypes.