Fig 1. Experimental design and methods used in individual experimental variants.

Lemna trisulca plants incubated in darkness for 24 h in control medium (a), with 15 μM Pb²⁺ (b), with 10^–3M H₂O₂ added for the last 3 h of incubation (c), with 100 U catalase (d), or with Pb and catalase simultaneously (e); plants pre-incubated in darkness for 24 h and then exposed to white light for 1 h (weak 50 μE m^-2s^-1 or strong 1000 μEm^-2s^-1) in control medium (f-g) or with Pb (h-i); plants pre-incubated in darkness for 24 h and then exposed to blue light (for 45 min weak 2 μE m^-2s^-1 and next for 45 min strong 113 μE m^-2s^-1) in control medium (j-k) or with Pb (l-m).