微塑料对DBP胁迫下生菜光合作用及品质的影响

Effects of microplastics and DBP on photosynthesis and nutritional 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10~15μm)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。

This study explored the effect of microplastics on the photosynthesis and quality of lettuce seedlings under the stress of dibutyl phthalate(DBP).The toxic effects of the compound pollution of polystyrene(PS,100~400 nm and 10~15μm)and DBP on lettuce(Lactuca sativa L.)was investigated using hydroponic culturing.Compared with DBP alone,the presence of PS reduced lettuce photosynthesis under the stress of DBP,including the net photosynthetic rate,stomatal conductance,and transient transpiration rate,while the internal CO2 concentration increased.This indicates that the non-stomatal factor is responsible for decreasing photosynthesis.Compared to the control and DBP only,the combined pollution of PS and DBP decreased optimal PSⅡefficiency and electron transfer efficiency,inhibited ribulose bisphosphate carboxylase oxygenase activity,and reduced chlorophyll content in the lettuce leaves,but significantly increased the ascorbic acid and glutathione content.In addition,the presence of PS with two particle sizes significantly reduced the soluble protein and sugar content in lettuce leaves treated with DBP and increased the nitrite content,indicating that the presence of PS aggravated the negative effects of DBP on lettuce quality.The combined pollution of PS and DBP significantly inhibited photosynthesis and glucose metabolism,which in turn decreased lettuce quality.