The inhibiting effects of competition of Helianthus turberosus on photosynthesis with Ambrosia trifida increased along with the density increase of Helianthus turberosus in the mixed population.

• 可见，菊芋竞争对三裂叶豚草的光合作用具有一定抑制作用，且抑制作用随着混种种群中菊芋密度的增加有增强的趋势。