sio2

Astaxanthin is a precious material and has many favorites for human; it is extracted from some creatures such as Haematococcus lacustris. Researchers try to maximize the production of this material. In this research effects of linoleic acid (LA), TiO2 and SiO2 Nanoparticles (NPs) were investigated on astaxanthin production, and expression of two astaxanthin metabolic pathway genes (CRTO and CRTR). The microalgae was cultured in BBM medium for 19 days autographically. In 3rd day, treatments were added to the cultures and astaxanthin measured in 3 days respectively in logarithmic and stationary phases, also RNA was extracted, Real-time PCR applied and Gene expression investigated in 11th. 30 µM LA and TiO2 NPs (40 mg L-1) induced 3.4 and 1.5 times astaxanthin production compared to the control, furthermore, CRTO and CRTR under 30 µM LA and SiO2 NPs (40 mg L-1) treatments displayed the highest gene expression. It was demonstrated that special concentration of Linoleic acid and TiO2 NPs, as inducers, could be used for astaxanthin production; also, Linoleic acid has a direct relationship with astaxanthin production and CRTO´s gene expression in the microalgae.

The use of nanotechnology as a diverse and applied discipline is ongoing in almost all areas of science. Fertilizers and nano-nutrients have the effective properties which help the production of plants depending on their needs to regulate the plant growth. Plants under stress conditions are willing to produce natural nanoparticles to continue their growth. Nano TiO2 has a high photocatalytic effect and as a catalyst, it is mainly used in water, electronic devices, conversion and storage equipment of Energy as suspension. Sources of SiO2 are very diverse, including natural nanoparticles, anthropogenic particles and engineering nanoparticles. Although, silicon in many crops is not an essential element for growth, it has beneficial effects on plants growth and development. Today, carbon nanotubes are one of the most important materials in industrial programs. These materials, with different methods and specific properties, can play an important role in the production of composite materials, application in medicine, electronic and energy storage. The Niger plant, with the scientific name of Goizotia abyssinica (L.F) Cass, belongs to the Asteraceae family. Its seed, are used in pharmacy, food industry, green manure and for feeding birds and cows. Therefore, the purpose of this experiment was to investigate the effect of type and concentration of three nanoparticles on some of germination characteristics and anthocyanins content in Niger medicinal-oily plant.   In order to evaluate the effect of three nanoparticles on seed germination of Niger, an experiment was conducted as factorial in a completely randomized design with four replications. The treatments of TiO2, SiO2, and CNT were as the first factor while their concentrations in four levels (zero, 10, 30 and 60 mg/l) were as the second factor. In this study the traits of germination percentage, germination rate and mean of daily germination, germination and vigour index, length, fresh and dry weight of radicle and plumule, anthocyanin content and radicle resistance percentage were measured.    The germination percentage, germination rate and mean of daily germination decreased by increasing of nanoparticles concentration. The favorable effect of TiO2 on germination index at the concentration of 30 mg/l and radicle dry weight at the concentration of 10 mg/l, was gained compared to control. The positive effect SiO2 on germination index and radicle dry weight at the concentrations of 10 and 60 mg/l, the anthocyanin content and the fresh and dry weight of plumule at the concentration of 60 mg/l was obtained compared to control. Also, the appropriate effect of CNT on germination index at the concentration of 10 and 30 mg/l, the anthocyanin content and radicle dry weight at the concentration of 60 mg/l and plumule fresh weight at the concentration of 30 mg/l, was observed. According to the results of this study, it seems that the effect of nanoparticles in plants, in addition to the plant, species, type and concentration of nanoparticles, varies depending on the growth stage and physiology of the plant. It seems that nanoparticles at some concentrations can increase the water absorption of seeds and increase seedling growth with their positive effects. Anthocyanins are produced by exposure to stress due to their antioxidant activity. In general, it can be stated that increasing the concentration of nanoparticles caused and increased the oxidative stress in plant. Therefore, it is recommended by investigating the bad effects of nanoparticles on plants, if necessary, use nanoparticles at low concentrations (less than 60 mg/l) to increase the plant's efficiency.   Highlights: The effect of nanoparticles kind and concentration on seed germination indices and anthocyanin content of Niger seedling. Investigating the interaction of nanoparticle type and concentration as the physical priming factor of seeds on seed germination of multi-purpose Niger plant.

Effect of SiO2 nanoparticles on rangeland plant of Bromus kopetdaghensis Drobov organs is accomplished through factorial test in a completely randomized design with four replications at Ferdowsi University of Mashhad, in 2014. Treatments included two levels of application (spray and impregnated with seeds), 5 concentrations level of SiO2 nanoparticles (1, 2, 10, 50, and 80 mg/l), and control (no SiO2 nanoparticles). Results showed that increase in concentration of nanoparticles, the plant organs such as height and weight parameters were decreased. However, SiO2 nanoparticles at low concentrations at the application of SiO2 nanoparticles method impregnated with the seed at a concentration of 10 mg/l and spraying nanoparticles at a concentration of 2 mg/l were increased plant height and weight, compared to treatment the control. Application of SiO2 nanoparticles are coated with seed treatments with a concentration of 10 mg/l was shown 24, 66 and 34 percent incensement, respectively for shoot dry weight, root dry weight and height compared to the control treatment. Application of spraying nanoparticles treated with 2 mg was shown 27, 68 and 35 percent incensement respectively for shoot dry weight, root dry weight and height compared to the control treatment. According to Bromus kopetdaghensis D. yield, it is suggested the method of SiO2 nanoparticles application impregnated with seed at a concentration of 10 mg/l due to lower consumption of nanoparticles, ease of nanoparticles use and being economical at natural lands.

In this study، the effect of nano-SiO2 in four levels of 0، 1، 2، and 3 percent (weight of cement) and the type of lignocellulosic materials on physical and mechanical properties of woodcement boards manufactured by old corrugated container (OCC) and rice husk have been investigated. Totally 8 treatments were taken that each one had three repetitions. Samples were provided according to DIN EN 634 and physical and mechanical properties، including modulus of rupture، modulus of elasticity، shear strength parallel to surface، hardness، water absorption and thickness swelling after 2 & 24 hours immersion in water، have been measured. The Results indicated that in case of using nano-SiO2، OCC-cement boards incorporating 1 percent and rice husk-cement boards incorporating 2 percent nano-SiO2 had the highest bending strength and modulus of elasticity. Shear strength parallel to surface and hardness were further in boards incorporating 2 percent nano-SiO2. Also، using rice husk in board manufacturing has decreased the water absorption compared to OCC.