Foliar application of silicon has little effect on hydroponically grown barley (Hordeum vulgare L.) / Foliarno dodajanje silicija ima malo učinka na hidroponsko gojen ječmen (Hordeum vulgare L.)

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.