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Carbon and nitrogen balance in Acorus calamus, a wetland species colonising littoral zones with a high trophic status, was studied under experimental conditions using water or sand culture with a defined composition of the nutrient solution. Influence of graded level of N (1.86, 7.5 and 18.6 mM) and/or forms of N (NH þ 4 versus NO À 3 ) on the content of non-structural carbohydrates, free amino acids, total C, and total N was studied in Acorus rhizomes and roots to find possible connection with a reduced growth of Acorus plants under high N and NH þ 4 -N nutrition described in our previous study [Vojtı´sˇkova´et al., 2004. Hydrobiologia 518: 9-22]. High N availability and pure NH þ 4 -N nutrition affected the C/N balance of rhizome and root systems of Acorus in a similar way. NH þ 4 -N was the only form of N elevated under the high N treatment. The major proportion of the total non-structural carbohydrates (TNC) was starch (91-93% and 51-64% in rhizomes and roots, respectively). The content of starch was significantly and negatively affected by high N availability (P=0.000), as well as by NH þ 4 -N nutrition (P=0.001). Amounts of simple soluble carbohydrates (sucrose, glucose, and fructose) were negligible in comparison to starch in rhizomes and branched roots (up to 5% of TNC), while roots without developed lateral roots (unbranched) contained up to 33% of TNC in the form of simple soluble sugars. Moreover, high hexoses/sucrose ratio, low starch/soluble sugars ratio, high content of N, and low C/N ratio support the notion that unbranched roots are metabolically active young roots with tissue differentiation in progress. A high content of free amino acids, typically with dominance of N-rich amino acids (Arg-46%, Gln-8%, Asn-7%), was found simultaneously with a low carbohydrate content under high N supply, which indicates that NH þ 4 received is effectively incorporated into the organic form by this species. Since the decrease in carbohydrate content was not accompanied by luxurious growth, other possible carbon consuming processes were discussed in relation to NH þ 4 nutrition. More dramatic changes in total N than C were found under high N availability resulting a shift in C/N ratio in favour of N. Although the shift towards N metabolism was obvious, no serious carbohydrate depletion occurred, which could explain the reduced growth of Acorus plants under high N and sole NH þ 4 -N nutrition described previously.

In her work, Julia Kristeva uses two disparate concepts: revolution and revolt. In this article we will try to outline these concepts as different approaches to the relations between power, art and psychoanalysis. By placing the concepts of revolt and revolution in dialogue with each other, and by pointing out that the dialogue departs from the notion of experience, we will attempt to reconstruct the important contribution that Kristeva's work offers. Her perspective reveals that artistic expression is linked to a specific kind of politics (dissolved politics). Kristeva's view of literary and psychoanalytic practice is then, we argue, something that can contribute to its realisation, albeit in a limited way.