Carbon,Nitrogen And Phosphorus Ecological Stoichiometry Characteristics Of Herbs In The Coastal Wetland Of Fujian,Zhejiang And Shanghai

Based on the theory of ecological stoichiometry,we colledted the plant samples of 7 plant species communities at 70 sampling sites in the coastal wetlands of Fujian,Zhejiang and Shanghai in southeastern China,The 7 plant species were Spartina alterniflora,Phragmites australis,Cyperus malaccensis var.Brevifolius,Suaeda australis,Scirpus mariqueter,Scirpus triqueter and Juncellus serotinus.The objectives were to explore the variations of C,N and P ecological stoichiometric characteristics in different species and organs with the latitude,mean annual temperature and climate zones in Fujian,Zhejiang and Shanghai.The results showed that:(1)Contents and stoichiometric ratios of C,N and P of different species were significantly different.The order of the contents of C of different species was P.australis>S.alterniflora>S.triqueter>S.mariqueter>J.serotinus>C.malaccensis var.Brevifolius>S.australis;N contents of S.mariqueter and S.triqueter were slightly higher than others,P contents of S.mariqueter and J.serotinus were slightly higher than others.The contents of C,N and P of C3(including:P.australis,S.australis,S.mariqueter,S.triqueter)and C4(including:S.alterniflora,C.malaccensis var.brevifolius,J.serotinus)plants were not significantly different.The contents of C,N and P of monocotyledon(including:S.alterniflora,P.australis,C.malaccensis var.brevifolius,S.mariqueter,S.triqueter,J.serotinus)and dicotyledon(S.australis)were significantly different.(2)C,N and P contents in different organs of herbs were:panicle>leaf>stem or leaf sheath,and were significantly different(p<0.05),because of different differentiation and function of different organs.Except panicle,contents of C in different organs had a certain relationship with dry biomass of the organs.(3)Ecological stoichiometry characteristics of N and P in leaves of herbs changed with latitude and annual temperature consistently in coastal wetland.N and P contents significantly decreased with increasing latitude(p<0.01),and significantly decreased with decreasing mean annual temperature(p<0.001),but the N/P did not show significant change and showed weak correlation with latitude and annual average temperature.(4)Leaf N/P did not show significant changes with variation of latitude and mean annual temperature,and correlated weakly.This may be due to the smaller range of latitude,leaf N and P increasing at the same time with increasing latitude(decreasing mean annual temperature),the same trend weakened N/P change with latitude and annual average temperature.Besides,the large variation of leave N and P,increased variability of N/P,resulting in the variation of N/P with latitude and annual temperature was covered.(5)With the climate zones northward,leaf N,P decreased significantly and N/P relatively small,this may be because a significant consistency in the distribution of temperature,climatic zones and latitude in the southeast coast of China.