Salt stress alleviation by seed priming with silicon in lettuce seedlings: an approach based on enhancing antioxidant responses
Seed germination and seedling growth are the stages most sensitive to salt stress, which can induce ion-specific effects and oxidative stress. Although silicon (Si) has been known to improve plant defense systems against stressful-conditions, little is known about seed priming with Si and mechanisms of Si-mediated alleviation of salt stress in seedlings. To further the modulation of salt-stress responses and their relation with Si, seed priming with calcium silicate (0, 0.05 and 0.1 mM Ca 2 SiO
... and 0.1 mM Ca 2 SiO 4 ) was used in lettuce seeds to improve seed germination and tolerance on subsequent salt-stress exposure (0 and 50 mM NaCl). The effect of Si-priming was assessed on germination, germination rate index and mean germination time and survival of seedlings in salt-stressful conditions supported by biochemical approach involving antioxidant responses. Overall results indicated that Si plays a role in alleviating the negative effects of salt stress by improving germination performance and displayed increased SOD, CAT and GR activities and reduced malondialdehyde and H 2 O 2 contents. Thus, our findings demonstrate that seed-priming with Si is an efficient management technique that can be used to alleviate deleterious effects of salt-stressful on germination of lettuce seeds and enhance salt tolerance of seedlings due the increased activity of ROS-scavenging enzymes.