Amino acids and carbohydrates in a metaboliccorrelation network. The correlation network of A. thaliana displays other distance relations of amino acids and carbohydrates compared to the reaction network in Fig. 5a. This representative example from sampling point 4 h light shows the color-coded pair distances of all metabolites belonging to the biochemical classes of the amino acids and of the carbohydrates. The typical separation of compounds according to their biochemical classes as found in the metabolic reaction network (see Fig. 5a) is not seen in the correlation networks independently of the sampling point and the parameter ω(data not shown). A distinct intra-class correlation which has been observed in most of the sampling points exists for Isoleucine(7), Tyrosine(11), and Valine(12). Some sampling points, however, exhibit correlations which hint to inter-class specific relations (e.g. serine(9) and sucrose(21)).