Effects of osmopriming on tomato (Lycopersicon esculentum M.) hybrid seed vigor under aging and salinity stress

Abstract

This study investigates the effects of osmopriming on tomato (Lycopersicon esculentum M.) hybrid seed vigor
under aging and salinity stress. Tomato seeds of the ZZ1 hybrid variety, stored for four years under natural
(aged) or -20°C (unaged) conditions were primed in 10% (w/v) polyethylene glycol (PEG) solution for 2 d at
20±1°C in the dark. The seed vigor was evaluated at 25±1°C for 7 d under normal (water) and 100 mM NaCl
conditions, respectively. Results show that the germination percentage (GP), germination index (GI) and mean
germination rate (MGR) of primed, aged seeds were significantly enhanced with a substantial increase in the
radicle length (RL), shoot length (SL) and total fresh weight (FW) compared with unprimed aged seeds.
Similarly, the GI, MGR and FW significantly increased in primed seeds compared with unprimed seeds under
salinity stress, while GP, RL and SL did not show significant differences. Furthermore, a decline in the relative
electrolyte leakage (REL) and in malondialdehyde (MDA) was detected in primed seeds during the imbibition
stage compared with unprimed seeds under aging and salinity stress. The negative correlations between seed
vigor and REL and MDA were observed which suggests that seed priming improves seed vigor under stress
conditions associated with a decrease in seed lipid peroxidation.