Table 3. Herbicides toxicity effects on the PSII electron transport efficiency (1-V_J) of IL and selected D1 random mutants, and corresponding R/S values.

Strains	Atrazine		Terbuthylazine		Linuron
	I50×10−7 M	R/S	I50×10−7 M	R/S	I50×10−7 M	R/S
	(±SE)		(±SE)		(±SE)
IL	2.4±0.11	/	1.0±0.08	/	1.1±0.05	/
P162S/F211S	19.7±1.57	8.2	5.9±0.26	6.2	2.0±0.17	1.9
M172L	2.2±0.03*	0.9	1.1±0.02*	1.1	1.1±0.06*	1.0
L200I	1.8±0.06	0.7	0.6±0.04	0.6	0.9±0.06	0.8
G207S	2.1±0.09*	0.9	4.3±0.18	4.4	1.3±0.09	1.2
I281T	2.0±0.07	0.8	0.7±0.02	0.8	1.3±0.05	1.2

The I₅₀ is the molar herbicide concentration, which induces 50% inhibition of the parameter 1-V_J. The R/S were calculated as ratios of mutant I₅₀ and I₅₀ of the reference strain; the asterisks indicate values that do not differ significantly from the IL strain at p≤0.05 (Mann-Whitney U Test). We considered that R/S<0.9 values define increased herbicide sensitivity, R/S>1.1 – increased herbicide resistance and 0.9≤R/S≤1.1 – no significant alterations in the mutants herbicide sensitivity relative to the reference strain.