| The sustainable development and quality improvement of artificial forests are not only crucial to achieving China’s carbon peaking and carbon neutrality goals but also a national strategic requirement for ecological civilization construction.However,there are widespread issues of soil degradation and nutrient imbalance in current plantation.Therefore,improving forest quality and enhancing carbon sequestration benefits are urgent issues that need to be addressed.Ecological stoichiometry is a tool for studying the coupling relationships between elements such as carbon,nitrogen,and phosphorus in ecosystems,which can indicate the self-organizing principles and adaptive laws of ecosystems.Changes in forest structure and soil biochemical processes during the growth and development of artificial forests may affect the ecological stoichiometry characteristics of the plant-litter-soil continuum,but there is currently insufficient understanding in this regard.Therefore,this study used a space-for-time substitution approach and selected different-aged Cryptomeria japonica plantations in rainy area of west China as the research object,including young forests(6 a),middle aged forests(12 a),near mature forests(23 a),mature forests(27,32 a),and over mature forests(46,52 a).Plants(mature leaves,twigs,and roots),litters(leave and twig litters),and soil(0-20cm)samples were collected,and indicators such as carbon(C),nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),sodium(Na),and magnesium(Mg)content were measured.The study explored the ecological stoichiometry characteristics,nutrient resorption efficiency and homoeostasis of different components(plants,litters,and soil)in different-aged Cryptomeria japonica plantations and analyzed the potential influencing factors..The research conclusions are as follows:(1)The average content of C,N,P,K,Ca,Na,and Mg in mature leaves of Cryptomeria japonica was 439.36 g/kg,12.57 g/kg,1.14 g/kg,4.35 g/kg,11.01 g/kg,0.09 g/kg and 1.39g/kg,respectively.There were significant patterns of changes in the content of different elements with increasing stand age,but there were some differences among different organs and components.With increasing stand age of Cryptomeria japonica,the N content of mature branches,leaves and roots,P content of mature twigs,N,P,Ca,and Mg content of twig litters,Ca and Mg content of leaf litters all showed an increasing trend overall,while C,N,and P content of leaf litters showed a decreasing trend.The P and Mg content in mature leaves,Mg content in mature twigs,P and Ca content in roots,and soil C,N,P,and Ca content increased first and then decreased overall with stand age.However,the Mg content in roots,K content in leaf litters and twig litters,and soil K and Mg content decreased first and then increased.The K,Ca,and Na content in mature leaves and twigs,and K and Na content in roots all showed an overall"N"-shaped increasing trend with stand age.(2)The ecological stoichiometry ratios of different elements showed distinct trends with increasing stand age,but there were variations among different plant organs and components.N:Ca ratio in mature leaves,N:P and N:Ca ratios in mature twigs,N:P,N:Ca,N:Na and N:Mg ratios in roots,and soil C:N and C:P ratios all increased with stand age.N:Na and N:Mg ratios in mature leaves,C:N,N:Na,and N:Mg ratios in mature twigs,C:N ratio in roots,and C:N,C:P,and N:P ratios in twig litters all decreased with stand age.N:K ratios in mature twigs,leaves and roots,N:K,N:Ca,N:Na,N:Mg ratios in leaf and twig litters,soil N:P,N:Ca,N:Na,and N:Mg ratios increased first and then decreased with stand age,while C:N and C:P ratios in mature leaves and C:P ratio in roots decreased first and then increased with stand age.(3)The N resorption efficiency of the twigs,and the N resorption efficiency,P resorption efficiency of leaves of Cryptomeria japonica increased with stand age,but the P resorption efficiency of the twigs showed a decreasing trend.The K resorption efficiency,Ca resorption efficiency and Mg resorption efficiency of twigs and leaves increased first and then decreased with stand age.The nutrient reabsorption efficiency in twigs and leaves of Cryptomeria japonica positively correlated with the nutrient content and ecological stoichiometric ratio of plants,and negatively correlated with litters.The relationship with soil varies due to element differences.In addition,the relationship(R~2)between nutrient status of plants and litter and nutrient reabsorption efficiency of Cryptomeria japonica were closer than soil.(4)The content of P and K in mature leaves were weakly homeostatic and plastic type,while the content of N,N:P,N:Ca showed homeostatic type,and the content of N,Mg in roots were weakly plastic type.The P contents,N:P,N:Na were plastic type,the N:Mg was weakly homeostatic type.Overall,the homoeostasis of K,Ca,Na,and Mg in plants>N homoeostasis>P homoeostasis,moreover,the homoeostasis of N content,N:P,N:K,N:Ca,N:Na,and N:Mg in mature leaves were higher than mature twigs and roots of Cryptomeria japonica.These results cloud verify the the content of K,Ca,Na,and Mg of plants in this area showed a strong stability,and consisted with"stable leaf nutrient concentration hypothesis"of plants.(5)Tree height,diameter at breast height and soil physical and chemical properties(such as soil C,N,P,etc.)were closely correlated with the element ecological stoichiometric characteristics of plant,litter,and soil.In general,the elements ecological stoichiometry characteristics of plants were mainly influenced by soil P and its labile components,while the elements ecological stoichiometry characteristics of litter were mainly regulated by soil bulk density,C,P,and active inorganic phosphorus(P).The elements ecological stoichiometry characteristics of soil e are mainly controlled by soil N and P.In summary,the ecological stoichiometric characteristics of the seven elements in the plant-litter-soil continuum of Cryptomeria japonica plantation in rainy area of west China showed significant stand age effects,and their variation patterns are influenced by their organs and components.The nutrient reabsorption efficiency of Cryptomeria japonica was closely related to the nutrient content and ecological stoichiometric ratio of plants,litters and soil,but was mainly regulated by the nutrient status of plants and litters.The leaves showed stronger stability than twigs and root with the change of soil nutrients.Soil physical and chemical properties(such as soil C,P and labile P components)were important indicators for regulating the ecological stoichiometric characteristics of plants,litter,and soil.These research results are helpful to deeply understand the nutrient variations in the plant-litter-soil continuum with the growth and development of Cryptomeria japonica plantation,and provide a theoretical basis for fertilizer management of Cryptomeria japonica plantation. 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