Table 3. Results of stepwise multiple regression using physiological and morphological characteristics. The analysis determined the best combination of variables related with NO₂, SO₂ reduction ability.

Gas types	Explanatory variables	R2	P
NO2	Chl b	0.671**	0.003
SO2	SLA	0.456*	0.032
	Chl b, MLleaf	0.648	0.081

The significance level represented by the abbreviations. *, P < 0.05; **, P < 0.01.