Common Euhydrophyte Functional Traits Variability And Environmental Adaptation

The plant traits that could respond to the ecology process intensely,indicate vegetation and ecosystem environmental change are been called plant functional traits.The research on plant functional traits variability and its environmental adaptation was greatly meaningful in clarifying the adaptation mechanism of plants to the environment.Terrestrial ecosystems such as subtropical forests,tropical rain forests,grasslands,shrubs are used as the main research objects in the intraspecies and interspecies variation of plant functional traits and environmental adaptation researching at present.The report on the aquatic ecosystem researching was rare at the same time.Euhydrophyte was been defined as the hydrophyte whose roots were fixed to the bottom substrate and leaves were immersed in water or floated on the water surface.It was related to the water environment closely with a wide range of distribution and has high adaptation to environmental changes.The survey of euhydrophyte communities and the collection of plant samples were carried out in 10 wetland plots in the middle and lower reaches of the Yangtze River.15common euhydrophyte species were collected.The intraspecies and interspecies variation of 13 functional traits(including leaf,root,and whole plant functional traits)were been analyzed.The relationship between plant functional traits and the environment was been analyzed based on combined environmental factors.The conclusions were mainly included in the following.1.The larger differences in the interspecific and intraspecific variation of the whole plant functional traits(Height,Branch,H/S),SLA,and SRL of euhydrophyte were shown in the coefficient of variation analysis.The functional traits of LN,RN,LC,RC,LS,RS,LCN,and RCN had smaller differences in the same time.The interspecies variations of each functional trait were larger than the intraspecies variations.Interspecies variation and intraspecies variation had the high explanatory power for 11 functional traits,which were shown by the results of Variance Partitioning Analysis,excluding LN and RN.In the traits as SLA,LCN,SRL,RN,RS,Height,Branch,and H/S,the interspecies variation had the higher explanatory power.In traits as LS and RCN,intraspecific variation had the higher explanatory power.But the co-explanatory power of intraspecific and interspecific variation for most functional traits was low,excluding the traits of LC and RC.These indicate that interspecies variation was the main source of euhydrophyte functional trait variation,and it was been strongly influenced by genes.2.The significant differences between floating-leaves plants and submerged plants in SLA,LN,LC,LCN,SRL,RS,Height,and Branch were been indicated by the results of the Mann-Whitney U test.The differences in LS,RN,RC,RCN,and H/S were not significant.Lower SLA,higher LN,LC,and LCN were been possessed by floating-leaves plants,while higher SLA,SRL,RS,Height,and Branch were been possessed by submerged plants.The research results showed that different photosynthesis strategies might have been adopted by different life-type euhydrophyte,but similar strategies for obtaining mineral nutrients might have been adopted by euhydrophyte.3.Significant or extremely significant correlations were been found in 47 pairs of plant functional traits among the 13 plant functional traits of euhydrophyte in the results of correlation analysis.The positive correlations were been observed in SLA and LN,SRL and RN,but the negative correlations in LC and LS,SRL and RC,were been observed.That showed close connections may exist among the functional traits of euhydrophyte,and there might be had inherent synergy and trade-offs among plant functional traits.4.Redundancy analysis was been performed between the euhydrophyte functional traits and the principal components of environmental factors.The positive correlation between SLA,SRL,LN,LS and ALT,TEM,EC,WT,and LLF were been shown,and the negative correlation between LON,NH₃-N,DEP,and PAN were been shown in the results.Height and LCN were negatively correlated with ALT,TEM,EC,TEM,and LLF.LON,NH₃-H,DEP,and PAN were positively correlated.LAT,TN,NO₃-N,WV were negatively correlated with Branch and RCN.And they were positively correlated with H/S.But the explanatory power to the euhydrophyte functional traits distribution of environmental factors was limited(35.20%).The euhydrophyte functional traits of leaf and root were shown a different pattern from the terrestrial plant by reference to the results of others'research.The euhydrophyte SLA had been enlarged,the efficiency of light utilization and carbon fixation had been improved to adapt to aquatic habitats.