Simulated climate warming and nitrogen deposition influence leaf traits and leaf trait spectrum in Solidago canadensis from China and North America

Temperature is a key factor that affects plant growth, and nitrogen（N） is an important resource for plant growth and photosynthesis. Changes in temperature and N may strongly influence the functional traits of invasive plants. The aim of this study was to predict the potential invasiveness of invasive plants in response to climate warming and atmospheric N deposition. We conducted a simulated warming and N deposition experiment at Chengdu. In this experiment, we selected Solidago canadensis from China and North America as the focal invader and set up four experimental treatments:（1） ambient,（2） warming（2℃ above the ambient）,（3） N addition(4 g N m-2 a-1 in the form of NH4NO3), and（4） warming plus N addition. We determined three leaf traits, leaf chlorophyll content, leaf area, and leaf dry matter content, as well as three relationships among the traits. Our results showed that Solidago canadensis from China had a lower leaf dry matter content than that from North America. Warming increased the leaf area of Solidago canadensis, and N addition increased its chlorophyll content. Sources and warming had significant effects on leaf area. The leaf area of S. canadensis from China decreased significantly with increasing leaf dry matter content. In the warming treatment, the leaf area of S. canadensis was significantly positively correlated with chlorophyll content; in the N addition treatment, the leaf area was significantly positively correlated with chlorophyll content and significantly negatively correlated with leaf dry matter content. These findings suggest that warming and N addition could enhance the ability of S. canadensis leaves to obtain resources. In addition, our results imply that climate warming and atmospheric N deposition may increase the invasion risk of Solidago canadensis.