菊芋对三裂叶豚草叶片光合特性的竞争机理

Mechanism of Photosynthetic Characters of Ambrosia Trifida in Competition with Helianthus turberosus

采用取代试验设计,研究了不同密度比条件下,菊芋对三裂叶豚草光合特性的竞争机理。结果表明:竞争条件下,菊芋具有光竞争优势,对豚草造成弱光胁迫,使豚草叶片叶绿素的含量下降,光合速率降低,蒸腾作用和水分利用效率受到抑制,气孔导度减小,但胞间CO2浓度无明显差异,非气孔限制是竞争条件下豚草光合速率下降的主要因素。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。

The effects of competition with Helianthus turberosus on photosynthesis of Ambrosia trifida were studied under different densities under series replacement experiments. The results showed the advantage of Helianthus turberosus in light competition led to weak light stress on Ambrosia trifida, which decreased leaf chlorophyll content, photosynthetic rate, transpiration rate and water use efficiency and stomatal conductance, but with no effect on internal concentration CO2 , so the nonstomatal limitation was the main restrictive factor of photosynthesis of Ambrosia trifida. 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.