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Abstract In this study, we investigated the composition of free amino acids and lactate (Lac) in polychaetes in river estuaries and inner bays using chromatographic techniques. Both l-amino acids and d-amino acids (d-asparagine, d-alanine (d-Ala), d-serine, d-aspartic acid, and d-proline (d-Pro)) were detected, indicating that polychaetes contain some d-amino acids. Some polychaete species exhibited notable amino acid levels, such as glycine in Capitellidae sp. and Thelepus sp., d-Pro in Glycera sp., and β-Ala in Scoletoma nipponica and Scoletoma sp.. High d-Lac levels were detected in Tylorrhynchus osawai and Hediste diadroma, (691 and 797 μmol/100 g-wet, respectively), with the d-form exceeding 98%. T. osawai was dominant in the upper tidal-sensitive zone, wherein other organisms were less abundant because of low salinity (3–8 PSU). Seasonal differences in the concentrations of components in T. osawai were observed, particularly a significant increase in d-Lac in the reproductive period. Notably, the d-Lac concentrations of T. osawai were higher upstream than downstream. Thus, d-Lac might be involved in strategies underlying adaptations to low salinity and reproductive activity. These results suggest that both the d-form of Lac and amino acids may play certain physiological roles in the life of polychaetes.

Abstract Premise The great variation of genome size (C‐value) across land plants is linked to various adaptative features. Flow cytometry (FCM), the standard approach to estimating C‐values, relies mostly on fresh materials, performing poorly when used with herbarium materials. No fern C‐value reports have been derived from herbarium specimens; however, the herbarium spores of some ferns remain highly viable for decades and are thus promising for further investigation. To explore this possibility, we evaluated herbarium spore collections of Ophioglossaceae ferns using FCM. Methods Flow cytometry was conducted on 24 spore samples, representing eight of the 12 genera of the Ophioglossaceae, using specimens ranging in age from 2.6 to 111 years obtained from five herbaria. Results Regardless of the genus or the source herbarium, high‐quality C‐value data were generated from 17 samples, with the oldest being 26 years old. Estimates of the C‐values from sporophytic tissues of known ploidy did not reveal any evidence of apomixis for the species surveyed here. We also detected a pronounced genome downsizing in Sceptridium polyploids. Discussion The recent success of FCM for C‐value estimation using spores provides a much more convenient method of utilizing “dry” refrigerated materials. We demonstrate here that herbarium spores of some ferns are also promising for this use, even for older specimens.