Induction of salt tolerance in tomato (Lycopersicon esculentum Mill.) seeds through sand priming.

Effect of sand priming on vigour and biochemical changes of two tomato varieties, 205 and 206, at various salinity levels (0, 50, 100 and 150 mM NaCl) were studied. Both varieties differ in their salt tolerance capability and are commonly raised in Zhejiang province. Seeds were mixed with sand particles diameter ranged between 0.5 mm to 2 mm containing 4 % (v/w) water, sealed in plastic box, and then were primed at 25 degreesC for 72 h. Final germination percentage (FGP), germination index (GI), vigour index (VI), root length, shoot length, fresh weight and dry weight were studied as tomato seed vigour markers in relation to malondialdehyde (MDA) contents, catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. Sand priming significantly improved FGP, GI, VI and seedling vigour attributes of both tomato varieties under salinity stress. Moreover sand priming treatments significantly enhanced the activities of CAT, POD, SOD and APX whereas reduced the accumulation of MDA contents under salt stress condition. Our results suggested that sand priming can serve as a promising method to enhance tomato seed vigour under salt stress condition probably through augmentation of antioxidant enzymes activities. Generally, var 206 responded better compared with var 205 at higher salinity stress.