UV-B affects within-seed biomass allocation and chemical provisioning

• Here we investigated the accuracy of measurements at the whole seed level in estimating seed and seedling quality. Specifically, we asked: 'Do measurements at the whole seed level mask important differences in testa or embryo quality?' and 'Are chemicals provisioned to seeds present in seedlings post-germination?' • We measured the allocation of biomass and distribution of UV-absorbing compounds to testas and embryos of Brassica rapa seeds derived from plants grown in the presence and absence of UV-B. The concentration of UV-absorbing compounds in cotyledons was also quantified. • Differences in seed quality were only detected when testas were analyzed separately from embryos. UV-B decreased testa mass by 18% and increased the concentration of UV-absorbing compounds in the testa by 158%. The increased chemical provisioning to testas was not evident post-germination, as the concentration of UV-absorbing compounds in cotyledons was independent of parental environment. • Our results suggest that measurements at the whole seed level conceal significant differences in testa quality, and chemicals provisioned to testas do not affect progeny chemistry during establishment.