Figure 3.

Cluster analysis of the Av-spectra of the cultivar 2 of Zea mays (Zm2, maize) and the cultivar 5 of Echinochloa crus-galli (Ec5, barnyard grass) for the experiment 2-2 with all 10 Av-spectra (A) and with the omission of the 100% Av-spectra (root tip) of barnyard grass (Av_Ec5_100%) (B). Cluster analysis was evaluated with the first derivation and vector normalization of the reduced frequency range (3,751–2,749 cm⁻¹ and 1,801–599 cm⁻¹), Ward's algorithm and Euclidian distance. The Av-spectra are averages (Av) of FTIR-ATR spectra of the different root segments (100% root tip, 0% root basis etc.; see Figure 1 for scheme, Table 2 for n, Table 1 for names of cultivars and proveniences).