Table 2.
SPAD values and plamochromic pigments in tobacco leaves inside and outside the greenhouse at various stages of flue-curing
| Treatment | Sampling temperature (°C) |
Continuous curing time (h) | SPAD | Chlorophyll a (μg g− 1) |
Chlorophyll b (μg g− 1) | Lutein (μg g− 1) | β-carotene (μg g− 1) |
|---|---|---|---|---|---|---|---|
| Inside the greenhouse | Fresh tobacco leaves | – | 36.2Aa | 286.06Aa | 202.99Aa | 150.30Ab | 1940.38Ab |
| 38 | 23.5 | 14.9Ab | 105.95Ab | 42.72Ab | 248.59Aa | 3657.98Aa | |
| 42 | 16.5 | 9.8Abc | 64.20Ab | 26.80Ab | 297.14Aa | 4127.06Aa | |
| 48 | 15 | 8.0Abc | 45.77Ab | 17.01Ab | 245.15Aab | 4489.59Aa | |
| 54 | 22.5 | 6.2Ac | 13.33Ab | 4.40Ab | 206.64Aab | 3524.01Aa | |
| Initially flue-cured tobacco leaves | – | – | 43.75Ab | 17.42Ab | 249.00Aa | 3794.68Aa | |
| Outside the greenhouse | Fresh tobacco leaves | – | 30.6Ba | 114.91Ba | 87.18Ba | 93.28Aa | 1207.53Aa |
| 38 | 23.5 | 13.4Ab | 13.37Aa | 7.94Ab | 118.40Ba | 1573.64Ba | |
| 42 | 16.5 | 9.5Abc | 5.12Aa | 3.68Ab | 112.31Ba | 1669.27Ba | |
| 48 | 15 | 7.8Abc | 4.83Aa | 3.50Ab | 115.36Ba | 1800.61Ba | |
| 54 | 22.5 | 3.0Ac | 3.88Aa | 2.53Ab | 139.42Aa | 1888.94Ba | |
| Initially flue-cured tobacco leaves | – | – | 6.74Aa | 4.83Ab | 122.23Ba | 1783.31Ba |
Different capital letters indicate that there were significant differences among different treatments at the same sampling temperature point. Different lowercase letters indicate that there were significant differences among different sampling temperature at the same treatments (P < 0.05). The values were the mean of three biological replicates