The effective quantum yield of photosystems [Y (I) and Y (II)] of <i>Arabidopsis thaliana</i> treated by HCH isomers.

<p>* and ** depict a statistically significant difference as compared to controls (<i>p</i><0.05 or 0.01 respectively, ANOVA’s test). Different letters above the columns of HCH isomer treatments show statistically significant differences between them (<i>p</i> = 0.05).