Effect of Nano silicone colloid pre-treatment on some germination indices and seedling physiological characteristics of wheat under drought stress

Wheat (Triticumaestivum) is a cereal grain and most important crops that is devoted 17 percent of arable land under cultivation in the world. 32 percent of the wheat-growing areas in developing countries experienced various types of stress during the growing season. Drought stress isone the most important problem that decreases the crop production. Wheat is one of the plants that can absorb a significant amount of silicon. Researchers have reported that silicon have numerous positive effects on the growth and yield of crops as well as the physiology and metabolism of different plants. Silicon reduced the effects of Salinity and drought stress and it seems the beneficial effect is mainly due to the effect of silicon on the growth of leaves, stems and other plantbased mechanisms. In addition, silicon helps plants to overcome the environmental stress. Seed priming technique is one of the ways to increase germination and emergence indices.

This study aimed to evaluate the effect of pre-treatment of silicon Nanocolloid on seed germination and some physiological characteristics of wheat seedling under drought stress was done in environmental stresses laboratory of Sari University of Agricultural Sciences and Natural Resources. A factorial experiment carried out based on randomized completely block design with four replications. Experimental factors were six drought levels including (0, -3, -6, -9, -12, -15 bar) and five Nanosilicon levels including (0, 15, 30, 45, 60 mg/l). Morvarid cultivar was used in this experiment. In order to seed treatment with nano-silicon solution, the seeds casting in containers containing different concentrations of nano-silicon and was kept for 12 hours at room temperature. Drought levels contains, -6, -9, -12 and -15 bar were used to create them using Michel and Kaufmann, respectively from zero, 143.18, 213.64, 267.98, 313.88, 354.36 grams of polyethylene glycol 6000 in 1 liters of distilled water were used. This experiment carried out in two stages. In first stage the morphological and germination indicesincluding germination percentage, germination index, germination rate, germination rate coefficient, mean of daily seed germination, daily germination rate and other indices were studied, and in second step, seedling physiological traits including prolin, concentration of Chl. a, Chl. b, carotenoid and other physiological traits were evaluated.

showed that, Nanosilicon applications increased the daily germination rate (12.5%) and mean of germination time (12.8%), but decreased germination percentage (6.1%) and germination rate (23.3%) and had not significant effect on mean daily germination. Drought stress decreased germination percentage (8.5%), germination rate (41.1%), but encourage the germination index (18.25). By increasing of drought stress to -3 bar, the Chla (45%), Chl b (53.3%) and carotenoide(49.8%) were increased, but with increasing of drought stress to -6 bar, these traits decreased significantly but the proline was increased to (93.3%). With increasing of Nanosilicon levels to 30 mg/lit and more, the traits of Chl b and carotenoid increased but had not significance differences. The interaction effect of drought stress and Nanosilicon particles on germination rate, Chl b and carotenoide concentrations were significant but on the other seed morphological and seedling physiological trait was not significant. Although chlorophyllandcarotenoid decreased with increasing drought stress from 0 to - 6 bar, butthis index was much more than control in the presence of silicon nanoparticles.It seems accumulation of proline and other metabolites in wheat and other plants, is a mechanism for drought tolerance and other stresses. It can also be concluded that the effect of various amounts of nano-silicon under drought stress on seed and seedling traits, are more noticeable than in normal condition and without stress.