Plant origin and maternal warming mediate seed germination responses of Solidago canadensis to microplastic stress

Experimental sources: The experimental subjects were Canadian goldenrod seeds from North America (SNA-A), Canadian goldenrod seeds from North America subjected to warming treatment (SNA-W), Canadian goldenrod seeds from China (SCN-A), and Canadian goldenrod seeds from China subjected to warming treatment (SCN-W). Microplastic concentration: Five mass fraction gradients were set at 0%, 1%, 2%, 4%, and 6%. Experimental period: From April 2025 to May 2025. The seed germination indicators mainly measured the bud length(mm), 7-day germination percentage(%),final germination rate(%), germination index, vigor index,first day of germination(d), Timson index and mean germination time（d）. Thousand-seed weight: In this experiment, the thousand-seed weight was determined by the hundred-seed weight method. One hundred seeds were randomly selected and weighed using a precision electronic balance with an accuracy of 0.0001g, and this process was repeated five times.