Effect of Silver Nanoparticles on Seed Germination and Seedling Growth in Thymus vulgaris L. and Thymus daenensis Celak under Salinity Stress

Germination represents a fundamental stage of plant life highly responsive to change of environmental conditions. Low germination percent and seedling establishment are basic problems in saline regions. One of the sensitive stages of plants to salinity is the germination stage. This study was conducted using a factorial experiment with three factors such as species with two levels (Thymus vulgaris L. and Thymus daenensis Celak), nanosilver in 4 levels (0, 10, 20 and 30 ml) and salinity in 4 levels (0, 100, 200 and 300 mM NaCl) using a completely randomized design in four replications in University of Kashan, Iran in 2016. Results showed that the interaction among species, salinity and nanoparticles was significant only for germination rate (P≤0.01). Silver nanoparticles increased germination percent, germination rate and root length up to 200 mM sanity, but they enhanced seed vigor and shoot length up to 100 mM salinity as compared to the control treatment. In 100 mM salt concentration, the 20 and 30 mL nano-silvers were effective, but for 200 mM salinity, the application of 10 mL nano-silver was effective.