Figure 2.

Cluster analysis of the Av-spectra of the 1:1 comparision of (A) Pisum sativum (Ps, pea) and Avena sativa (As, oat) as well as (B) Zea mays (Zm, maize) and Echinochloa crus-galli (Ec, barnyard grass). Here exemplarily represented Ps3 and As3 of experiment 1-2 (A) as well as Zm3 and Ec1 of experiment 2-2. Entire results are shown in Supplementary Tables 1, 2. 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).