The Relationship Between Leaf Traits And Photosynthetic Efficiency Of Phragmites Australis In Different Soil Salinity In Qinwangchuan Salt Marsh Wetland

Plant leaf functional traits is the important indicators to measure plant growth condition,the chlorophyll fluorescence can directly reflect the strength of the plant photosynthesis under the stress condition,leaf traits and chlorophyll fluorescence parameters of relevance is the direct embodiment of tightness.The study of the correlation about leaf traits and the chlorophyll fluorescence parameters can help understand the balance mechanism between plant leaves photosynthetic product distribution and energy distribution.The correlation analysis of leaf traits(leaf blade size,specific leaf area)-photosynthetic efficiency is helpful to the understanding of the accumulation and dissipation of photosynthetic products in heterogeneous environment,and to explore the influence about the carbon assimilation product distribution on photosynthesis under the condition of limited resources.This provides a theoretical basis to understand physical build and photosynthetic,fluorescence characteristics of plant leaves under the stress habitat conditions.In this paper,the correlation analysis between leaf characters and chlorophyll fluorescence characteristics of Phragmites australis in Qinwangchuan salt marsh wetland was studied by using correlation and standardized spindle estimation method(SMA),according to the study area soil salt content,the reeds population were set three samples(I,II and III),the correlation of the leaf traits and photosynthetic,fluorescence parameter,and leaf traits(leaf size,specific leaf area)and photosynthetic efficiency correlation were analyzed,the allocation mechanism between energy and photosynthetic product of the wetland plants under heterogeneous habitats were analyzed,showed special blade configurations and survival mechanism of the salt marsh wetland plant in special habitat conditions.The results show that:(1)There were significant differences in wetland community characteristics under different soil salt conditions(p < 0.05).With the decrease of the soil salt content,the height,and aboveground biomass of the population of Phragmites australis increased gradually,the density and PAR(photosynthetically active radiation)showed decressed changging trends,and no obvious change in soil moisture content.(2)With the decrease of soil salt content,there were significant differences inleaf trats and photosynthetic parameters of reeds population(p < 0.05).Leaf area,chlorophyll content,plant height,the net photosynthetic rate(Pn),water use efficiency(WUE),saturated vapor pressure difference(VPD)and transpiration rate(Tr)have a trend of gradual increase,the leaf thickness and the intercellular CO2concentration(Ci)was decreased gradually,the specific leaf area was presented increases-decreases changing trends,but leaf dry weight and the stomatal conductance(Gs)exhibited were showed opposite changing trends.(3)The fluorescence chlorophyll parameters of Phragmites australis were significantly different in different plots(p < 0.05).With the decreasing of the soil salt content,the effective quantum yield of PSII photochemistry(Y(II)),the photochemical quenching(QP)and the electron transport rate(ETR)presented firstly reduced then increased changing trends.The non-photochemical quenching(NPQ),the quantum yield of regulatory energy dissipation(Y(NPQ))and the maximum efficiency of photosystem(PS)II photochemistry(Fv/Fm)displayed increased-decreased changing trends.The quantum yield of non regulatory energy dissipation(Y(NO))showed a trend of increase gradually change trend.(4)There were significant differences in the correlation between leaf characters and photosynthetic parameters of Phragmites australis in different plots(p < 0.05).The correlation between leaf characters and chlorophyll fluorescence parameters was found significantly different in different plots(p < 0.05),and the correlation between photosynthetic parameters and chlorophyll fluorescence parameters(p < 0.05)were significantly different in different wetland populatuion significant difference.(5)The relationship between the size and the photosynthetic efficiency of Phragmites australis showed significant difference in the different soil salt content(p< 0.05).There was a significant positive correlation between leaf area and Y(NO)in three plots(p < 0.05).SMA slope was presented firstly decreased and then increased trend.Leaf thickness and Y(NO)showed a significant negative correlation in three middle habitat conditions(p < 0.05),the slope of SMA displayed decreased-increased changing trend.(6)The relationship showed significant different between specific leaf area and the photosynthetic efficiency of Phragmites australis in three samples(p < 0.05).There were significant negative correlation(p < 0.01)between specific leaf area and the effective quantum yield of PSII photochemistry(Y(II)),specific leaf area and the electron transport rate(ETR),the absolute value of SMA slope presented firstly increased after decreased changing trends.The correlation analysis of leaf character construction pattern and the photosynthetic efficiency of plants can reflect the photosynthetic mechanism and special survival mechanism formed under long-term stress habitat.Phragmites australi in the high salt content of soil sample,because of the intense sunlight,high soil salt content and so on the stress habitat forced it to choose small blade-low specific leaf area of the leaves of building model,it is advantageous to achieve the optimal allocation of carbon assimilation product under heterogeneous habitat and implement the dissipation of excess light energy,so as to maintain plant normal growth and achieve the purpose of self-protection;Growth under low soil salt content habitat of reed plants,with the improvement of the living environment as the loss of water and salt stress along,as larger plants shading,forcing its choose large blade –high specific leaf area blade build model not only can improve the problem of shortage of the plants absorb light energy under shade environment,and realizing the maximization of photosynthetic yield and the reasonable distribution of the limited energy plant leaves.