Table 3.
The effect of exogenous kinetin on maximum and effective quantum efficiency, expressed as ratios of variable to maximum and variable to initial PSII quantum efficiency in the light and in the dark-adapted states in the leaves of coffee seedlings under optimum and cold stress conditions.
| Parameter | Optimum Conditions | Cold Stress Conditions | ||
|---|---|---|---|---|
| Control | Kinetin | Cold | Cold + Kinetin | |
| Fv’/Fm’ | 0.52 ± 0.02 Aa | 0.56 ± 0.06 Aa | 0.42 ± 0.05 Ba | 0.40 ± 0.05 Ba |
| Fv/Fm | 0.75 ± 0.04 Aa | 0.75 ± 0.02 Aa | 0.57 ± 0.14 Aa | 0.58 ± 0.05 Aa |
| Fv’/Fo’ | 1.08 ± 0.10 Aa | 1.30 ± 0.33 Aa | 0.72 ± 0.15 Aa | 0.69 ± 0.14 Ba |
| Fv/Fo | 3.02 ± 0.71 Aa | 3.00 ± 0.25 Aa | 1.46 ± 0.75 Ba | 1.43 ± 0.31 Ba |
Within a row, different capital letters, (A, B) denote statistically significant differences between the parameter means within temperature treatments, whereas treatment means followed by the same small letter, (a) are not statistically significantly different between the kinetin treatments (p < 0.05, Newman Keuls’ test). Data are expressed as means ± S.D (n = 3).