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The concentrations of avenanthramides (AVAs), hydroxycinnamic acids (HCAs), a sucrose-linked truxinic acid (TASE), and certain agronomic parameters were analyzed in organically and conventionally grown oats. Three cultivars of oats (i.e. Freja, Sang, and Matilda) were grown according to standards for both conventional and organic farming in Sweden, from 1998 to 2000. Two levels of nitrogen (N) and three replicates were included. Overall, there were significant differences between years, cultivars, and N rate for AVA concentration in the grains, but there were no differences in concentration as a consequence of the conventional or organic cropping system used. The AVA content was higher in the samples grown in 2000, particularly in the cultivar Matilda, and was negatively affected by higher N rates. The HCAs showed cultivar and year differences, but were not influenced by N rates or the cropping system. The HCA content was highest in Matilda, and was significantly lower in samples grown in 1999. The concentration of TASE differed only between years, and was about 100% higher in samples from 1999, compared with samples from 1998 and 2000. The AVA and HCA concentrations were negatively correlated to the yield and specific weight of the grains and positively correlated to the protein content. Conversely, the concentration of TASE was positively correlated to the yield. The specific parameters responsible for the variation in the phenolic compounds are not known, but it seems that factors affecting the yield and/or the specific weight also affect the concentrations of AVAs, HCAs, and TASE in oat grains.

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The physiological basis for ecological processes is in many cases little understood. The purpose of this work was to link 3 important physiological processes in algae -photosynthesis, carbon uptake and antioxidant defence -to life form. The organisms used were the morphologically similar filamentous green algal species Cladophora glomerata and Ulva procera, which seemingly occupy the same niche when they co-occur in dense belts in the upper littoral zone of the brackish Baltic Sea in summer. Their life strategies are different: the annual C. glomerata usually stays attached throughout summer, while the ephemeral U. procera can appear and disappear from the same site from week to week. The algae were growing in the field under exactly the same conditions (mixed stands) and were immediately used in experiments at a field station. Fundamental ecophysiological differences were found between the 2 species. (1) Higher photosynthetic activity was detected in U. procera. (2) More shade-adaptations were found in U. procera, and more sun-adaptations in C. glomerata. (3) C. glomerata uses a proton pump for HCO 3 -transport, and carbon uptake does not depend on periplasmic carbonic anhydrase. This is an advantage in dense algal belts with longer periods of carbon limitation. (4) C. glomerata invests more in carotenoid protection against oxidative stress, including high carotenoid/chlorophyll ratios and a functional violaxanthin xanthophyll cycle. (5) U. procera was more sensitive to oxidative stress created by UV-B radiation than C. glomerata, which correlates with a more effective intracellular (carotenoid and enzymatic) defence against oxidative stress in C. glomerata. (6) H 2 O 2 in the seawater medium had a negative effect on photosynthesis in C. glomerata, but not in U. procera. This suggests that a high release of H 2 O 2 by U. procera under oxidative stress may damage C. glomerata. While the ecophysiological traits of C. glomerata seem to be directed toward persistence, those of U. procera seem to be more engaged with large but short-term gains. This is in accordance with their different life strategies.

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