The usage of silicon fertilisation in order to mitigate the oxidative stress and to improve the resilience of barley subjected to drought

Drought causes huge agricultural and economic losses worldwide. Silicon (Si) is considered abeneficial element for plants. It mitigates stress caused by salinity, drought, and high and low temperaturesby promoting antioxidant production. However, the underlying mechanisms are still notelucidated. We investigated Si fertilisation effect on photosynthetic parameters, trichome number,leaf optical properties, as well as profiles of amino acids and polyphenols in barley exposed towater shortage. Silicon was applied in three growth stages: (i) before the flag leaf emergence;(ii) prior to the grain filling phase; (iii) at the grain filling phase start. Drought negatively impactsphotochemical efficiency, stomatal conductance, photosynthetic pigment content, and leaf reflectiveand transmissive properties. Si application between flag leaf emergence and grain fillinghad the strongest effect on light reflectance. Among all analyzed phenolics, saponarin was themost abundant in all samples, irrespective of water regime and Si supply. Caffeoyl ester was theonly hydroxycinnamic acid showing significant accumulation with the latest applied Si comparedto no added Si upon drought. The major amino acids in barley leaves were glutamate, glutamine,aspartate, asparagine, and serine. Aspartate content was the highest in leaves exposed to droughtwithout Si addition, while lysine was the most accumulated in the leaves supplemented by Si atthe grain filling phase start. Proline was 2.5 times more abundant in the leaves exposed to droughtregardless of Si treatment. Taken together, although Si did not mitigate drought stress effects, itseffect was dependent on the barley growth phase prior to supplementation.Book of Abstracts / 4th International Conference on Plant Biology [and] 23rd SPPS Meeting, 6-8 October 2022, Belgrad

Silicon mitigates negative impacts of drought and UV-B radiation in plants

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

Different Concentrations of Potassium Silicate in Nutrient Solution Affects Selected Growth Characteristics and Mineral Composition of Barley (<i>Hordeum vulgare</i> L.)

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 (Si0.5), 1 (Si1) or 1.5 (Si1.5) 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 Si0.5 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 Si0.5, plants showed the best performance in terms of their physiological characteristics and growth