Table 10.
The effect of the nitrogen level on the boll shell protease and peptidase activities of the two Bt cotton cultivars in 2016.
| Cultivar | N rate (kg/ha) | Protease activity (mg g−1 FW h−1) | Peptidase activity (μmol g−1 FW h−1) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| 10 DAF | 20 DAF | 30 DAF | 40 DAF | 10DAF | 20DAF | 30DAF | 40DAF | ||
| SK-1 | 0(CK) | 1.36f | 1.68de | 1.78f | 1.81e | 0.49f | 0.58de | 0.61f | 0.62e |
| 75 | 1.72e | 1.57e | 2.07e | 2.31d | 0.59e | 0.55e | 0.69e | 0.76d | |
| 150 | 2.09cd | 2.13cd | 2.41cd | 2.73bc | 0.70cd | 0.71cd | 0.79cd | 0.88bc | |
| 225 | 2.22c | 2.30bc | 2.89ab | 3.01ab | 0.73c | 0.75bc | 0.92ab | 0.96ab | |
| 300 | 2.78a | 2.74ab | 3.04a | 3.24a | 0.90a | 0.88ab | 0.96a | 1.02a | |
| SK-3 | 0(CK) | 1.44f | 1.49e | 1.57f | 1.83e | 0.51f | 0.52e | 0.55f | 0.62e |
| 75 | 1.47f | 1.74de | 2.32de | 2.41d | 0.52f | 0.60de | 0.76de | 0.79d | |
| 150 | 1.95de | 2.33bc | 2.36cd | 2.53cd | 0.66d | 0.76bc | 0.77de | 0.82cd | |
| 225 | 2.51b | 2.45abc | 2.64bc | 3.06a | 0.82b | 0.79abc | 0.85bc | 0.97a | |
| 300 | 2.90a | 2.95a | 3.02a | 3.25a | 0.92a | 0.94a | 0.96a | 1.03a | |
Symbol SK-1 and SK-3 are cultivar Sikang1 and Sikang3 respectively, CK is Control. DAF is acronym of “days after flowering.” Same letter among treatments within each sampling date represent non-significant difference (LSD test at 0.05 significance level).