| Light gradient | Logistic equation parameters | ||||||
| Growth limitation (k) | Undetermined coefficient (a) | Undetermined coefficient (b) | Determination coefficient (R2) | Levene (F) | Significant level (P) | ||
| CK | 4.54 | 2.34 | 0.023 | 0.991 | 8679.578 | 2.27 × 10−6 | |
| 2 Needle | 5.704 | 2.8 | 0.027 | 0.988 | 5312.808 | 4.74 × 10−6 | |
| 3 Needle | 6.108 | 4.469 | 0.039 | 0.986 | 3631.549 | 8.39 × 10−6 | |
| 4 Needle | 3.296 | 3.712 | 0.028 | 0.998 | 23,730.768 | 5.02 × 10−7 | |
| 6 Needle | 3.699 | 2.86 | 0.024 | 0.996 | 11,918.374 | 1.41 × 10−6 | |