Nanopriming of Tomato (Solanum lycopersicum) Seeds Against Heavy Metal Stress During Germination and Seedling Formation

Abiotic stress can have a negative impact on plant growth. Heavy metal is one of the examples. One approach to overcome this issue is to use seed priming. The priming used in this study was nanopriming. We used colloidal silica nanoparticles (size of 10 nm) as the priming agent and copper (Cu) and barium (Ba) as the model heavy metals. This treatment was implemented for tomato (S. lycopersicum var. Momotaro) seed germination. The results showed that the presence of heavy metals during germination may lead to prolonging the germination time. The presence of Cu and Ba at 1 ppm could increase germination time by 28.38% and 26.9%, respectively, compared to control. When primed seeds were subjected to heavy metal stress, the use of silica nanopriming could reduce the germination time by 10.45% for Cu and 11.54% for Ba compared to the unprimed seeds. This evidence demonstrated that nanopriming could make seeds more resilient to heavy metal stress. We also found that heavy metal ions became less detectable in the seedlings when nanopriming was applied. This ion transport alteration essentially allowed seeds to cope with heavy metal stress. This method can be potentially used on various kinds of crops and heavy metals.