Study On Leaf Functional Traits Of Caragana Korshinskii With Different Planting Years

Plants have formed different trait combinations to adapt to environmental changes during longterm evolution.The mean value of plant functional traits can reveal the adaptation strategies of plants to the current environment.In this paper,9 different planting years(3a,5a,10a,20a,30a,40a,50a,60a,70a)of Caragana korshinskii plantation were taken as the research object,and 9 typical plots were set up.The data of leaf economic,hydraulic traits and soil physical and chemical properties were measured.The relationship between the two groups of traits(trade-off synergy)and the relationship with soil factors were analyzed.Redundancy analysis(RDA)was used to reveal the driving factors of leaf ecological adaptation of Caragana korshinskii in different years.To clarify the carbon-water coupling mechanism of Caragana korshinskii leaves and the adaptation strategy under arid environmental conditions,and provide a theoretical basis for vegetation restoration and management in desert areas.The main results are as follows:(1)The economic and hydraulic traits of different planting years were significantly different(P<0.05).With the change of planting years,the acquisition strategy of Caragana korshinskii leaves changed from "rapid investment-consumption" to "slow investment-income".(2)There were significant differences in crown width,plant height and ground diameter of Caragana korshinskii among 9 different planting years(P<0.05).These three growth indexes significantly affected the economic and hydraulic traits of Caragana korshinskii leaves,and were negatively correlated with leaf economic and hydraulic traits except leaf thickness,leaf tissue density,stomatal density and maximum stomatal conductance(P<0.05).(3)There was no correlation between leaf hydraulic conductivity and hydraulic vulnerability(P>0.05),indicating that there was no trade-off between hydraulic efficiency and hydraulic safety.(4)With the increase of years,leaf economic traits and hydraulic traits are coupled to adapt to the harsh desert environment.(5)RDA(Redundancy analysis)analysis showed that soil factors explained 72.05%of the variance of leaf economic traits of Caragana korshinskii.The water content of 20-40 cm soil layer,total nitrogen of 0-10 cm soil layer and bulk density of 20-40 cm soil layer were the driving factors affecting leaf economic traits;Soil factors explained 76.63%of the variance of leaf hydraulic traits,The driving factors affecting leaf hydraulic traits were 10-20 cm soil water content 0-10 cm and 20-40 cm soil organic matter;Soil water content is the main influencing factor of Caragana korshinskii functional traits.In summary,the economic traits and hydraulic traits are coupled with each other.The combination of the two sets of traits is helpful to understand the carbon-water balance of plants more comprehensively,analyze the driving factors of soil factors on plant growth,and further understand the environmental adaptation strategies of plants.It is of great significance to the vegetation restoration in this area and has a certain guiding role in the scientific management of Baijitan Nature Reserve.