Ecological Stoichiometric Characteristics Of Typical Halophytes Under Different Salinity Gradients In The Yellow River Delta

The Yellow River Delta is one of the three major estuary deltas in my country,and the coastal saline-alkali land is widely distributed.The vegetation structure in this area is simple and there are few types.The natural vegetation is mostly halophytes,but the saline-alkali wasteland is widely distributed and it is very difficult to improve.Ecological stoichiometry has been a hot research topic in recent years.Therefore,this experiment is to explore the ecological stoichiometric characteristics of typical halophytes under different salinity gradients in the Yellow River Delta.The dominant species of three types of halophytes under different salinity gradients in the Yellow River Delta.The salt-repellent plant Phragmites australis,the polysalt plant Suaeda glauca,the salt-secreting plant Aeluropus littoralis and Tamarix chinensis are the research objects,and traditional methods such as field observation and indoor measurement and analysis are used.In combination,analysis and determination of the ecological stoichiometric characteristics,salt and nutrient content of soil and plant samples.It is expected to provide a certain theoretical basis for ecological protection and ecological restoration,and to ensure the orderly reproduction and reproduction of various plant species in the ecosystem.The main research conclusions show that:1.The C content of the three different types of halophytes is lower than the global average.The C content of the roots,stems and leaves of polysalt plants is significantly lower than that of salt secreting plants and salt-repellent plants.The C content of the leaves of polysalt plants is significantly lower than that of roots and stems There is no significant difference in C content between salt-secreting plants and salt-repellent plants;the N content of the three different types of halophytes is the highest in leaves and significantly higher than that of roots and stems.Under the three salt gradients,the P content is represented by salt-repellent plants and The leaves of salt-secreting plants are significantly higher than roots and stems.The content of roots in polysalt plants is higher than that of stems and leaves under mild and severe salinity.The content of N and P in polysalt plants is the highest under mild and moderate salinity,and the content of N and P is the highest under heavy salinity.,The salt-secreting plants have the strongest N and P accumulation ability.The three types of plants all showed the lowest leaf C/N and C/P.There were no significant differences in C/N and C/P between the leaves of different plant types under different salt gradients.Under mild and moderate salt soils,salt accumulation.The C/N and C/P content of plant roots,stems and leaves are lower than those of salt-repellent plants and salt-secreting plants.Under heavy salinity,the C/P of roots and stems of salt-repellent plants are significantly higher than that of polysalt plants and salt-secreting plants.The C/N of plant roots and stems is significantly higher than that of salt-secreting plants and salt-repellent plants.Under mild and severe salinity,the N/P of polyhalogenous plants is significantly higher than that of roots and stems.Under moderate salinity,the N/P of the three plants P did not show a significant difference.2.All the cations of the three types of halophytes show the salt island effect,and the content distribution satisfies the root<stem<leaf.Under the three salt gradients,salt-repellent plants have the highest total potassium content,and polysalt plants show total sodium.With the highest content,under mild salinity,the salt-secreting plants have the highest total potassium content,and under moderate and severe salinity,the salt-secreting plants have the highest total calcium content.The salt-repellent plant TK has a very significant positive correlation with plant N and P(P<0.01),the total amount of cations of polyhalide plants has a very significant negative correlation with plant C,C/N(P<0.01),and the salt-secreting plant TNa has a very significant negative correlation with N and N.There was a very significant positive correlation(P<0.01).3.The soil C and N contents of the three types of halophyte communities clearly show that the 0-20cm content of the surface layer is significantly higher than that of 20-40cm and40-60cm.The soil P content of the three types of halophyte communities increases with the depth of the soil profile.The content did not change much.The change trend of soil C/P and N/P of each plant community is basically the same as the change trend of soil C and N.Both soil C/P and N/P of the community appear to decrease with the increase of soil salinity gradient.Under moderate salinity,the soil C/N of salt-repellent plant and polyhalogenous plant communities increases with the increase of soil depth,while the soil C/N of salt-secreting plant community first increases and then decreases with soil depth.The soil C/N of the plant and salt-secreting plant communities increases with the increase of the soil depth.The soil C/N of the salt-repellent plant community first increases and then decreases with the soil depth.The soil C/N of the salt-accumulating plant and salt-secreting plant communities increases with the salt content.The increase in the gradient first increased and then decreased,showing that the C/N was the highest under moderate salinity,and the soil C/N of the salt-repellent plant community increased with the increase in the salinity gradient.4.The soil anions and cations of the three types of halophyte communities are mainly Na~+and Cl~-.The soils of the three types of plant communities under mild salinity do not show obvious differences in different soil layers.In saline soil,the content of anion and cation in the 0-20cm surface layer of polyhalophyte and salt-secreting plant communities is significantly higher than that of 20-40cm and 40-60cm.The content of anion and cation in the soil of salt-repellent plant community is under different soil layers under heavy salinity.The difference is not significant,the content of 0-20cm under moderate salinity is significantly higher than that of 20-40cm and 40-60cm.The soil of salt-repellent plant community showed a significant positive correlation with soil cations under mild and severe salinity(P<0.05),and a significant negative correlation with soil cations under moderate salinity(P<0.05);the soil of polyhalophyte community showed a significant positive correlation with soil cations(P<0.05);,Under heavy salinity,TC,TN,C/P,N/P are extremely significantly positively correlated with soil anions and cations(P<0.01);under mild salinity,TN,N/P and soil p H,C/N was significantly correlated(P<0.05),and TC and C/P were significantly correlated with soil anions and cations under moderate and severe salinity(P<0.05).5.Under different salinity gradients,the three types of plant ecological stoichiometry and soil factors show certain correlations and differences.Under mild and moderate salinity,the ecological stoichiometric characteristics of salt-repellent plants and the ecological stoichiometric characteristics of community soil showed a significant correlation(P<0.05).Under mild and moderate salinity,the TC of polyhalophytes and soil TN,C/P,N/P showed a significant positive correlation(P<0.05).Under heavy salinity,polyhalogenes TP and soil TC showed a very significant positive correlation(P<0.01),soil C/N,C/P and Plant ecological stoichiometry showed a significant correlation(P>0.05);under mild salinity,the N/P of salt-secreting plants was significantly positively correlated with soil TC(P<0.05).Under moderate and severe salinity,the ecological stoichiometry of salt-secreting plants was extremely significantly correlated with soil TN and N/P(P<0.01).Salt-repellent plants were significantly correlated with soil salinity under mild salinity(P<0.05),and polyhalophytes were significantly correlated with soil salinity under moderate and severe salinity(P<0.05).