Maternal effects allow offspring to cope with changing environments. While the immediate effects of climate warming and nitrogen (N) deposition are well documented, their maternal effects have been little studied. We conducted a 6-year maternal experiment with Solidago canadensis, native to North America and invasive in China, and two offspring experiments to address how maternal warming, maternal N-addition and population source interacted to influence offspring performance. Maternal effects of warming and N-addition on seed traits, leaf dry matter content, and whole-plant biomass were stronger in S. canadensis offspring from China than in offspring from North America. Matched maternal-offspring environments allowed offspring to perform better compared to mismatched environments; offspring grown under warming flowered and produced seeds within a growing season only when their maternal plants were previously exposed to warming. Offspring environments influenced its performance and also modulated maternal effects. We suggest that the maternal effects of simulated climate warming and N deposition could vary ranges, and our findings imply that maternal warming could advance the reproductive phenology of offspring.

(1) Seed mass: we collected the seeds from maternal plants and air-dried them, selected 100 seeds from five mesocosms per maternal environment, and determined their air-dried mass (mg); the thousand-seed mass (mg) was calculated as follows: hundred-seed mass × 10. (2) Seed germination: seed germination was checked daily; the seed germination rate (%) was calculated as follows: (the number of germinated seeds/the initial number of seeds) × 100%. (3) Chlorophyll content: we selected three leaves from each individual and recorded three readings with a portable chlorophyll meter (SPAD-502, Konica Minolta, Japan) per leaf, and then all readings per individual were averaged. (4) Leaf dry matter content (LDMC): we determined the mass of a water-saturated fresh leaf after rehydrating it at room temperature for 24 h, and then determined its dry mass after oven-drying at 85 °C for 24 h; LDMC (mg g^-1) was calculated as the ratio of leaf oven-dry mass to leaf water-saturated fresh mass. (5) Flowering and seed-setting date: the onset of the first flowering and seed-setting was observed every 1–3 days; from the observations, we could determine the number of days from 1 April (i.e., day of year, DOY) for flowering and seed-setting phases. (6) Whole-plant biomass: at the end of the experiment, we harvested all plants and separated them into shoots and roots; all harvested plants were oven-dried at 65 °C for 48 h and then weighed; the whole-plant biomass (g) was defined as the sum of dry shoot biomass and dry root biomass. (7) Shoot/root ratio: we calculated a shoot/root ratio based on shoot biomass and root biomass.

README_ZhouFunctEcol2021.xlsx contains metadata for each of the following datasheets:

Zhou_FE2021_biomass.csv file contains the shoot biomass, root biomass, and whole-plant biomass of offspring individuals grown under different conditions.

Zhou_FE2021_chlorophyll.csv file contains the leaf chlorophyll content of offspring individuals grown under different conditions.

Zhou_FE2021_flowering date.csv file contains the flowering date of offspring individuals grown under different conditions.

Zhou_FE2021_leaf dry matter content.csv file contains the leaf dry matter content of offspring individuals grown under different conditions.

Zhou_FE2021_seed germination.csv file contains the seed germination rate of maternal individuals grown under different conditions.

Zhou_FE2021_seed mass.csv file contains the seed mass of maternal individuals grown under different conditions.

Zhou_FE2021_seed-setting date.csv file contains the seed-setting date of offspring individuals grown under different conditions.

Zhou_FE2021_shoot root ratio.csv file contains the shoot/root ratio of offspring individuals grown under different conditions.