微塑料对DBP胁迫下生菜光合作用及品质的影响

In order to explore the effects of the application amount of microplastics on the photosynthesis and quality of lettuce seedlings under the stress of dibutyl phthalate (DBP), taking green leaf lettuce (Lactuca sativa L.) as the research object, a hydroponic experiment was used to study the phytotoxic effects of combined pollution of polystyrene (PS, 100 - 400 nm and 10 - 15 μm) and DBP with two different particle sizes on lettuce seedlings. The results showed that: compared with the single DBP treatment, the presence of PS decreased the photosynthetic parameters of lettuce in the DBP treatment, such as net photosynthetic rate, stomatal conductance and transpiration rate, while the intracellular carbon dioxide concentration increased, indicating that the decrease in photosynthesis was caused by non - stomatal factors. Compared with the control and single DBP pollution, the combined pollution of DBP and PS significantly decreased the maximum light energy conversion efficiency of PSⅡ, electron transfer efficiency and chlorophyll content in lettuce leaves, hindered the synthesis of ribulose - 1,5 - bisphosphate carboxylase, while the contents of ascorbic acid and glutathione in lettuce roots and leaves increased significantly. In addition, the presence of PS with two particle sizes significantly decreased the contents of soluble protein and soluble sugar in lettuce leaves under DBP stress and increased the nitrite content, indicating that the presence of PS aggravated the impact of DBP on the quality of lettuce. The research shows that the combined pollution of PS and DBP inhibits the photosynthesis and sugar metabolism of lettuce, thus reducing the quality of lettuce.

为探索邻苯二甲酸二丁酯(DBP)胁迫作用下微塑料施用量对生菜幼苗光合及品质的影响,以绿叶生菜(Lactuca sativa L.)为研究对象,采用水培试验研究两种不同粒径的聚苯乙烯(PS,100~400 nm和10~15 μm)和DBP复合污染对生菜幼苗的植物毒性效应。结果表明:与单一DBP处理相比,PS的存在降低了DBP处理中生菜的光合作用参数,如净光合速率、气孔导度和蒸腾速率,而胞内二氧化碳浓度增加,表明光合作用的降低由非气孔因素导致。与对照和单一DBP污染相比,DBP和PS复合污染明显降低了生菜叶片中PSⅡ最大光能转换效率、电子传递效率和叶绿素含量,阻碍了二磷酸核酮糖羧化酶的合成,而生菜根系和叶片中抗坏血酸和谷胱甘肽含量显著增加。此外,两种粒径PS的存在均显著降低了DBP胁迫下生菜叶片中可溶性蛋白与可溶性糖的含量,增加了亚硝酸盐含量,表明PS的存在加剧了DBP对生菜品质的影响。研究表明,PS和DBP复合污染抑制了生菜的光合作用和糖代谢,从而降低了生菜的品质。