Investigating the germination characteristics of Chickpea (Cicer arietinum) in response to titanium dioxide nanoparticles priming and drought stress

Extended Abstract Introduction: Drought stress, as abiotic and multidimensional stress, has severe effects on plant growth. One of the new approaches in the management of drought stress is the use of nanoparticles. Nanoparticles infilterate the seeds and increase nutrient and water uptake and ultimately, improve germination. The present research was conducted to evaluate the effects of titanium dioxide nanoparticles on chickpea plant germination factors to modify the negative effects of drought stress. Materials and Methods: A factorial experiment was conducted in a completely randomized design with four replications on chickpea seeds of Arman cultivar in the Plant Sciences Research Institute of the Ferdowsi University of Mashhad in 2019. Seeds were primed with concentrations of 0, 5, 10, 15, and 20 mg L-1 titanium dioxide for 24 hours. The seeds were cultured in sterilized Petri dishes. Drought stress was applied using polyethylene glycol 6000 with 0, -2, -4 and -8 bar osmotic potentials. Results: The analysis of variance results showed that the interaction effect of drought stress and titanium dioxide nanoparticles was significant on germination rate, the number of normal seedlings, seed vigor index, germination index, length of seedling, radicle length, and radicle dry weight. All germination traits were inhibited as a result of drought stress. On the other hand, the presence of titanium dioxide nanoparticles partially decreased this inhibition in some traits. Germination percentage, germination rate, normal seedling percentage, seed vigor index, germination index, epicotyl length, radicle length and radicle dry weight decreased as a result of stress. Conclusion: At all drought stress levels, the concentration of titanium dioxide nanoparticles up to 20 mg L-1 significantly improved traits such as germination percentage, seed vigor index, epicotyl length, and epicotyl dry weight. It seems that nanoparticles can stimulate cell activity and increase the transformation of reserves to translocatable material and consequently, improve germination characteristics. Thus, the application of titanium dioxide nanoparticles up to a concentration of 20 mg L-1 can partially reduce the negative effects of drought stress on the germination characteristics of chickpeas. Highlights: 1- Germination percentage and seed vigor index of chickpea increased with the application of titanium dioxide nanoparticles up to 20 mg l-1 at all drought stress levels. 2- The radicle length and dry weight of chickpea increased by titanium dioxide nanoparticles. 3- The negative effects of drought stress on chickpea seed germination decreased by titanium dioxide nanoparticles.