石油烃对鳗草(Zostera marina)幼苗光合作用的毒性效应研究OA北大核心

To evaluate the effects of water-accommodated fractions(WAFs)on photosynthesis in Zostera marina seedlings,0,2.5,5,10,20,and 40 mg/L WAFs were applied for 8 days.The changes in photosynthetic pigment content(chlorophyll a and b),maximum photochemical quantum yield(Fv/Fm),fluorescence quenching parameters(QNP and qL),and photosynthetic electron transfer rate of the seedlings were studied.It was combined with the transcriptomics of 0(Group CG),5(Group A),10(Group B),20(Group C),and 40 mg/L(Group D)treatment groups to observe the differential expression of genes associated with the photosynthetic pathways.The toxic ef-fects on the photosynthetic system and underlying mechanisms under WAF stress were explored.The results showed that during the 8-day experimental period,a WAF concentration of less than 5 mg/L did not significantly impact chlorophyll a,chlorophyll b,and Fv/Fm in the seedlings.At concentrations greater than 5 mg/L,these pa-rameters were markedly reduced by 12.47%,16.65%,and 6.01%,respectively in the 40 mg/L group.A WAF con-centration of less than 10 mg/L had no remarkable effects on the qL and rETR.However,at concentrations greater than 10 mg/L,these parameters were significantly suppressed by 59.82%and 58.12%in the 40 mg/L group.At a WAF concentration of greater than 2.5 mg/L,the QNP increased markedly by 6.6%,9.03%,13.11%,11.92%,and 10.72%,respectively,in each treatment group on the 8th day.These findings indicate that low concentrations(2.5 and 5 mg/L)of WAF had a relatively small impact on the photosynthetic system of Z.marina seedlings;however,the photosynthetic system was damaged under medium-high concentrations(10,20,and 40 mg/L).Transcriptomics indicated that the number of differentially expressed genes in Groups B and C were 4 272 and 3 254 genes,respec-tively,compared to Group CG.The maximum number of differentially upregulated genes in Group B was 3 219,and that of downregulated genes in Group D was 1 135.Transcriptomics revealed that the photosynthesis pathway was significantly affected by WAF stress.