钼与聚苯乙烯微塑料对紫花苜蓿幼苗生长和抗氧化能力的影响

Effects of molybdenum and polystyrene microplastics on growth and antioxidant capacity of alfalfa seedlings

试验旨在探究重金属钼(Mo)、聚苯乙烯微塑料(PS-MPs)单一及复合胁迫对紫花苜蓿幼苗生长和抗氧化能力的影响。以紫花苜蓿为研究对象,检测不同浓度的Mo(0、0.1、1.0、10.0、50.0、100.0 mg/L)与PS-MPs(0、5、10、20、50、100 mg/L)对紫花苜蓿幼苗的生长和抗氧化指标的影响。结果显示,Mo单一胁迫下,低浓度的Mo(0.1、1.0 mg/L)促进了叶绿素的合成,叶绿素A、叶绿素B和总叶绿素的含量上升,高浓度的Mo(50 mg/L)会抑制苜蓿的生长指标、叶绿素含量、抗氧化酶活力,增加丙二醛(MDA)含量。PS-MPs单一胁迫下,PS20组紫花苜蓿幼苗的生长指标及叶绿素含量均低于PS0组,MDA含量高于其他组,PS100组抗氧化酶活力均受到抑制。在复合胁迫下,Mo-PS5组紫花苜蓿的过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)活性及MDA含量均显著低于Mo-PS0组;与Mo-PS0组相比,Mo-PS20组紫花苜蓿的生长指标均降低,MDA含量最高,Mo-PS100组抗氧化酶活力均显著降低(P<0.05)。研究表明,Mo与PS-MPs的单一胁迫以及复合胁迫均能够抑制紫花苜蓿幼苗的生长,复合胁迫时低浓度的PS-MPs可以缓解Mo胁迫造成的氧化损伤,而高浓度的PS-MPs会加剧Mo胁迫所造成的生长抑制及氧化损伤。

The experiment aimed to investigate the effects of single and combined stress of heavy metal molybdenum(Mo)and polystyrene microplastics(PS-MPs)on the growth and antioxidant capacity of alfalfa seedlings.Alfalfa was used as the research subject,and the effects of different concentrations of Mo(0,0.1,1.0,10.0,50.0,100.0 mg/L)and PS-MPs(0,5,10,20,50,100 mg/L)on the growth and antioxidant indicators of alfalfa seedlings were detected.The results showed that under single Mo stress,low concentrations of Mo(0.1,1.0 mg/L)promoted the synthesis of chlorophyll,and the content of chlorophyll A,chlorophyll B,and total chlorophyll increased.High concentrations of Mo(50 mg/L)inhibited the growth indicators,chlorophyll content,and antioxidant enzyme activity of alfalfa,and increased the content of malondialdehyde(MDA).Under single PS-MPs stress,the growth indicators and chlorophyll content of alfalfa seedlings in the PS20 group were lower than those in the PS0 group,and the MDA content was higher than other groups.The antioxidant enzyme activity in the PS100 group was inhibited.Under combined stress,the activities of catalase(CAT),peroxidase(POD),superoxide dismutase(SOD),and the content MDA in the Mo-PS5 group of alfalfa were significantly lower than that in the Mo-PS0 group.Compared with the Mo-PS0 group,the growth indicators of alfalfa in the Mo-PS20 group were all reduced,and the MDA content was the highest,and the antioxidant enzyme activity in the Mo-PS100 group was significantly reduced(P<0.05).The study showed that both single stress of Mo and PS-MPs,as well as their combined stress,could inhibit the growth of alfalfa seedlings.Under combined stress,low concentrations of PS-MPs could alleviate the oxidative damage caused by Mo stress,while high concentrations of PS-MPs would exacerbate the growth inhibition and oxidative damage caused by Mo stress.