Effects of Microplastics on Seed Germination and Seedling Growth of Tamarix chinensis under Salinity Gradients

Yang Zixuan; Sun Tao

doi:10.14083/j.issn.1001-4942.2025.12.005

Abstract：To explore the effects of microplastics on seed germination and seedling growth of Tamarix chinensis under salt stress,a multifactor stress experiment was conducted to analyze the response relationship of seed germination and seedling growth.The study examined the single or combined effects of different mass frac-tions of microplastics(polyethylene,PE,0.001%,0.01%,0.1%,0.25%,0.5%,0.75%and 1%,7 gradi-ents),NaCl(0.1%,0.5%,1.0%and 1.5%,4 gradients),and ammonium nitrogen(NH4 Cl,0.01%,0.025%,0.05%,0.075%and 0.10%,5 gradients)on indicators including seed germination rate,germina-tion index,vigor index,mean germination time,recovery and final germination rates,as well as seedling traits such as plant height,root length,fresh weight,chlorophyll content,and antioxidant capacity.The results showed that under salinity gradients,low concentrations(0.001%,0.01%and 0.1%)of PE exerted stronger inhibitory effects on seed germination and seedling growth,while moderate-to-high concentrations(0.25%,0.5%,0.75%and 1%)of PE alleviated these inhibitions or even promoted the seed germination and seedling growth.Among which,the germination rate of seeds treated with 0.75%PE was the highest in all salinity lev-els,and with the increase of salinity,the seed germination index and vigor index under 0.75%PE treatment were decreased.Treatments with 0.25%,0.5%,0.75%and 1%PE could alleviate the aboveground growth in-hibition of seedlings under salt stress.With the increase of salinity,chlorophyll content of T.chinensis seed-lings treated with microplastics were declined,while SOD and POD activities,and MDA content exhibited the trend of first increasing and then decreasing.Above all,under salinity gradients,the effects of PE exhibited a trend of low inhibition and moderate-to-high alleviation on seed germination and seedling growth of T.chinen-sis,and as salinity continued to increase to 1.0%and 1.5%,the alleviating effect of PE were weakened.