Fig. 1.

Degree of arbuscular mycorrhizal fungi colonization of roots and arbuscules formation. Values are means ± SE. (n = 4). Lower case letters (a, b, c) denote significant difference between means according to Fisher LSD test at P ≤ 0.05. G, soil from Gliwice site (HM_low); B, soil from Bytom site (HM_mod); P, soil from Piekary Śląskie site (HM_high); NS, nonsterilized soil; S, sterilized soil; F%, percentage of segments showing internal colonization; M%, average percentage of colonization of root segments; A%, percentage of arbuscules in the whole root system