Ecdysteroid content and distribution in plants of genus Potamogeton

Species of the genus Potamogeton L. growing in European North-East Russia were studied for the presence of ecdysteroids. Coupled HPLC/RIA showed that all Potamogeton species studied (P. alpinus Balb., P. berchtoldii Fieb., P. compressus L., P. gramineus L., P. lucens L., P. natans L., P. pectinatus L. and P. perfoliatus L.) contain 20-hydroxyecdysone, ecdysone and some unidentified minor compounds in the concentration range 0.2–4.0 μg ecdysone equivalents/g dry wt, depending on the species, growth stage and plant part studied. Detailed study of 20-hydroxyecdysone distribution in individual plants of P. pectinatus L. revealed that highest content of ecdysteroids is associated with points of active growth (170–250 μg/g dry wt in apical leaves of main and side-shoots). The presence of ecdysteroids in pondweeds and the pattern of their distribution within individual plants indicate a possible role in the interaction between plants and herbivorous arthropods in aquatic ecosystems.