| Vitamin contents (mg/100g dry weight) | |||
| Organic soil culture | Hydroponic culture | ||
Natural sun light | Artificial sun light | 1% collagen water solution | Liquid fertilizer | |
Total ascorbic acid | 367.5 | 262.5 | 450.0 | 434.0 |
α-tocopherols | 12.8 | 27.5 | 20.2 | 12.1 |
γ-tocopherols | 3.4 | 5.0 | 4.6 | 3.0 |