| Light gradient | Logistic equation parameters | ||||||
| Growth limitation (k) | Undetermined coefficient (a) | Undetermined coefficient (b) | Determination coefficient (R2) | Levene (F) | Significant level (P) | ||
| CK | 7.029 | 3.115 | 0.034 | 0.993 | 6799.026 | 8.65 × 10−8 | |
| 2 Needle | 15.8 | 4.526 | 0.042 | 0.990 | 2704.86 | 5.46 × 10−7 | |
| 3 Needle | 23.725 | 5.034 | 0.046 | 0.989 | 2224.663 | 8.07 × 10−7 | |
| 4 Needle | 16.355 | 3.761 | 0.038 | 0.982 | 1970.999 | 1.03 × 10−6 | |
| 6 Needle | 18.865 | 4.089 | 0.040 | 0.977 | 1338.513 | 2.23 × 10−6 | |