Table 2: Chlorophyll pigments and fluorescence of leaves of cotton seedlings grown under Cd stress.

Cd levelsChlorophyll pigmentsChlorophyll fluorescence
Chl aChl bChl a/b / NPQ
( / )

0 µM0.044 ± 0.00a  
(0.00)
2.72 ± 0.13a  
(0.00)
0.016 ± 0.003a  
(0.00)
0.49 ± 0.05a  
(0.00)
0.49 ± 0.01a  
(0.00)
0.81 ± 0.02a  
(0.00)
0.03 ± 0.08a  
(0.00)
500 µM0.021 ± 0.01b  
(−52.27)
2.22 ± 0.27a  
(−19.12)
0.011 ± 0.005a  
(−33.83)
0.33 ± 0.03b  
(−32.65)
0.34 ± 0.01b  
(−30.61)
0.65 ± 0.02b  
(−19.75)
0.05 ± 0.03a  
(55.17)

Values are the means ± SE of three replications. Variants possessing the same letter are not statistically significant at P < 0.05. Values in parenthesis show percent relative increase (+) or decrease (−) over the related controls.