Abstract: The effects of different nitrogen and phosphorus levels on the nutritive organ phenotypic plasticity of invasive Chromolaena odorata were studied by a greenhouse pot experiment. The results showed that branch number, branch length, total leaf number, total leaf area, total biomass, stem biomass and leaf biomass of C. odorata increased significantly with the increase of nitrogen and phosphorus levels. The ratio of root biomass to aboveground biomass decreased significantly with the increasing nitrogen and phosphorus levels, while the stem biomass fraction increased notably at 0.05 g·kg^-1 of nitrogen or phosphorus treatments and remained stable thereafter. Leaf mass fraction reduced first and then increased remarkably with the increasing nitrogen level, but it was less affected by the phosphorus levels. Leaf area ratio, the ratio of leaf area to root mass, specific leaf area and relative growth rate of C. odorata increased significantly with the increasing nitrogen and phosphorus levels, but had no differences when the phosphorus levels were ≥0.05 g·kg^-1 except the relative growth rate. Phenotypic plasticity indexes of branch number, branch length, total leaf number, total leaf area, total biomass, stem biomass, leaf biomass, root mass fraction, the ratios of root biomass to aboveground biomass and leaf area to root biomass of C. odorata were higher than that of other parameters, and the phenotypic response to nitrogen nutrient was also stronger than that to phosphorus. The results indicated that nitrogen and phosphorus levels had significant effects on the growth of C. odorata. C. odorata could modify its morphology, structure, biomass accumulation and allocation to adapt to the changing nutrient conditions, and thus demonstrated a strong phenotypic plasticity in response to different nitrogen and phosphorus nutrient levels.

Key words: Quercus aliena var. acuteserrata, water, spectral reflectance, throughfall elimination, photosynthetic pigment