Effects Of Nitrogen-Water Combined Disturbance On Resource Trade-off Strategies For Different Functional Plant Seedlings

Plants allocate limited available resources to build different functional traits.The optimal allocation is called the plant resource trade-off strategy.By assessing the different functional plant resource balance strategies under nitrogen-water combined disturbance,it is possible to explore how the resource plants can adjust the ecological strategy to adapt to the environment,to understand the resource trade balance between different organs of plants,and to obtain the trade-off relationship between resources and resources.The coniferous species Pinus massoniana,broadleaf deciduous tree Zenia insignis and broad-leaved evergreen tree Machilus pauhoi were studied.The experiments were performed with different gradients of nitrogen addition and drought stress.The changes of leaf,stem,root and whole plant functional characters and soil microbial community structure were determined by morphological observation,physiological and biochemical experiments,plant anatomical structure microstructure and stable isotope.The response status of plants under disturbance was systematically analyzed.The main results are as follows:(1)The effect of nitrogen addition on the growth rate of three plants was only in 0-4 weeks.The effect of water regulation on the growth rate was adaptable with the increase of drought stress time.(2)The response of different functional plants to nitrogen-water complex interference was different due to the difference of biological characteristics such as leaf configuration,transport water system structure and root absorption efficiency,but the correlation of core functional traits was consistent.(3)The core functional traits between different functional plant organs converge on the same axis,which shows a high degree of convergence of resource balance strategies among organs.(4)Under the resource imbalance configuration,P.massoniana can effectively utilize a resource,while improving the uses efficiency of the other resources to accelerate the growth;and M.pauhoi in the resource imbalance configuration,once a resource is difficult to obtain,it will lead to other resources to reduce the amount of access to ensure their own survival and security.Z.insignis could be not easily affected by the change of resources and environment.(6)The composition characteristics of soil microbial community were related to the root functional traits of different functional plants,but the correlation with the aboveground traits was not significant.(7)Nitrogen and water resources can not only have a direct effect on growth through their own processes,but also indirectly affect plant growth through plant carbon assimilation.The results showed that the functional trade-offs of different functional plants and plants were highly acclimatized under nitrogen-water combined disturbance.Under the unbalanced allocation of nitrogen and water resources,different plants showed a resource trade-off strategy with their own characteristics.The results could provide a theoretical basis for the adaptation of various functional plants to environmental change in the background of climate change.