The distribution of tested cultivars in PCA plot created on the basis of Chl <i>a</i> fluorescence data.

<p>The first two components, accounted about 86% of total variation: 1^st was related to measured values (FM, FV, F1-F5), 2^nd was highly correlated with calculated parameters (RC/ABS, (1-Vj)/Vj and PI. Cultivars tested in unpolluted site- green boxes; polluted site- red boxes.