Due to climate change, plants are being more adversely affected by heatwaves, floods, droughts, and increased temperatures and UV radiation. This review focuses on enhanced UV-B radiation and drought, and mitigation of their adverse effects through silicon addition. Studies on UV-B stress and addition of silicon or silicon nanoparticles have been reported for crop plants including rice, wheat, and soybean. These have shown that addition of silicon to plants under UV-B radiation stress increases the contents of chlorophyll, soluble sugars, anthocyanins, flavonoids, and UV-absorbing and antioxidant compounds. Silicon also affects photosynthesis rate, proline content, metal toxicity, and lipid peroxidation. Drought is a stress factor that affects normal plant growth and development. It has been frequently reported that silicon can reduce stress caused by different abiotic factors, including drought. For example, under drought stress, silicon increases ascorbate peroxidase activity, total soluble sugars content, relative water content, and photosynthetic rate. Silicon also decreases peroxidase, catalase, and superoxide dismutase activities, and malondialdehyde content. The effects of silicon on drought and concurrently UV-B stressed plants has not yet been studied in detail, but initial studies show some stress mitigation by silicon.

This study was undertaken to determine the effect of potassium silicate (K₂SiO₃) on the physiological and growth characteristics and elemental composition of barley plants. Hydroponically grown barley (Hordeum vulgare L.) var. Wilma was exposed to four different levels of Si in the form of K₂SiO₃ at concentrations of 0 (Si₀), 0.5 (Si_0.5), 1 (Si₁) or 1.5 (Si_1.5) mM Si. Plants were analyzed for root length, number of dry leaves, number of trichomes, electron transport system activity in mitochondria (ETS), leaf pigment content and elemental composition of roots and leaves. Treatment with Si_0.5 significantly increased the concentration of total chlorophylls, root length and ETS activity in barley. Plants with no Si added to the nutrient solution had significantly more dry leaves than plants from all Si-treated groups. Necrosis was observed in Si₀ plants, while leaf damage was not visible in treated plants. According to the results of the study, we evidenced that plants were stressed due to Si deficiency. The addition of K₂SiO₃ significantly affected the concentration of Si, K, Ca, Cl, S, Mn, Fe and Zn in roots and leaves of barley. In barley treated with Si_0.5, plants showed the best performance in terms of their physiological characteristics and growth.

Common buckwheat and Tartary buckwheat are pseudocereals and grow worldwide. Due to the high concentration of flavonoids, buckwheats are potential sources of smart food. Tartary and common buckwheat are traditionally grown in mountain regions of China, Korea, the northern parts of India, Bhutan, and Nepal. Plants that grow in high elevations are exposed to intense UV radiation, which can harm susceptible sites in the plants. Plants defend themselves against intense radiation by synthesising UV-absorbing compounds. Drought will probably become more frequent and intense due to climate change. UV radiation and drought are environmental parameters that present stress to the plants. These impacts can be synergistic or antagonistic. Selenium (Se) and silicon (Si) can protect plants exposed to UV radiation or drought since Se acts as an antioxidant. Silicon is an abundant element in Earth’s crust. It is present as a liquid or an amorphous or crystalline solid phase in the soil. Selenium and silicon are not essential elements for vascular plants, but they may positively affect plants. Thus, they can be added to the growth media to improve crop yield and quality, enhance resistance to biotic and biotic stress and improve plant growth.

Silicon is an element widely distributed on the earth’s crust. It can ameliorate stress in plants grown in unfavorable conditions. Barley is an important cereal used as a staple food. In our experiment, barley was grown on a floating hydroponics system in a greenhouse. Plants were stabilized in pots containing rockwool. Half of the plants were sprayed with potassium silicate (0.25 ml 6% K2SiO3 L-1) every ten days for 35 days. The vitality of plants during their growth was monitored by measuring the potential photochemical efficiency of photosystem II. After 16 and 35 days of silicon application, shoot length, root length, and fresh and dry biomass were measured. At the end of the experiment, the number of leaves and shoots, specific leaf area, leaf optical properties, and lipid peroxidation were determined as well. The potential photochemical efficiency of photosystem II was close to 0.8 and unaffected by the addition of silicon, indicating a good condition of the plants. Results showed lower leaf reflectance for silicon-treated plants in UVA, UVB, and blue light wavelengths, possibly due to a layer of potassium silicate on leaves. After 16 days, silicon-treated plants’ fresh shoot weight and root length were higher than in control plants. Results showed that additional foliar application of silicon does not cause stress in the barley plant. Izvleček Silicij je pogost element v zemljini skorji in lahko znižuje stres rastlin, ki rastejo v neugodnih razmerah. Ječmen je za ljudi pomembno žito, saj spada med osnovna živila. Poskus smo izvedli na plavajočem hidroponskem sistemu v rastlinjaku na Biotehniški fakulteti. Rastline so bile ukoreninjene v lončkih s kameno volno. Polovico rastlin smo škropili s kalijevim silikatom (0,25 ml 6% K2SiO3 L-1) vsakih deset dni. Med rastjo smo spremljali vitalnost rastlin z merjenjem potencialne fotokemične učinkovitosti fotosistema II. Po 16 in 35 dneh nanašanja Si, smo izmerili velikost poganjkov, dolžino korenin ter svežo in suho biomaso. Na koncu poskusa smo prešteli število listov in poganjkov, določili specifično listno površino, optične lastnosti listov in stopnjo lipidne peroksidacije. Potencialna fotokemična učinkovitost fotosistema II je bila v vseh tretmajih blizu 0,8, kar je nakazovalo na dobro stanje rastlin. Rezultati so pokazali nižjo odbojnost listov pri rastlinah, škropljenih s Si v UVA, UVB in modrem spektru valovnih dolžin, najverjetneje zaradi nastale plasti kalijevega silikata na listih. Po 16 dneh so imele s Si tretirane rastline večjo svežo maso poganjkov in daljše korenine kot rastline brez dodanega Si. Rezultati so pokazali, da škropljenje s silicijem ne povzroča stresa v ječmenu.