Salt addition over short and long durations does not prime
plants for an increased-induced PPO and TPI response to insect
herbivory
There was no significant interaction between salt and herbivory on PPO
and TPI levels at all time intervals (all P > 0.05).
Furthermore, salt application had no effect on PPO and TPI levels,
regardless of insect herbivory (all P > 0.05).
Herbivory, however, led to a significant increase in the PPO activity
and TPI levels, regardless of salt application (Figure 8A : PPO;Figure 8B : TPI; all P < 0.05). There were no
significant increases in PPO levels after herbivory at 7 days of salt
treatment (P > 0.05). Salt addition over short and
long durations did not prime tomato plants for a faster-induced response
in terms of PPO and TPI levels to insect herbivory.
Na+ ions
accumulate in tomato plants upon salt treatment
Salt treatment of leaves led to increased leaf Na+content in a dose-dependent manner (Figure 9; F(2, 15) = 262.2, P < 0.0001). The
Na+ content in leaves was 786.8 ± 63.83 mg/kg in 0 mM
treated leaves, 6575 ± 358.3 mg/kg in 100 mM leaves, and 10497 ± 374.8
mg/kg in 200 mM treated leaves.