A Biostimulant Based on Silicon Chelates Enhances Growth and Modulates Physiological Responses of In-Vitro-Derived Strawberry Plants to In Vivo Conditions.

The purpose was to assess the effects of a biostimulant based on silicon chelates in terms of alleviation of the impact of in vivo conditions on strawberry (Fragaria × ananassa cv. 'Solnechnaya polyanka') in-vitro-derived plants. As a source of silicon chelates, a mechanocomposite (MC) obtained through mechanochemical processing of rice husks and green tea was used. Root treatment of plants with 0.3 g L-1 of MC dissolved in tap water was performed at 2 weeks after planting. Control plants were watered with tap water. The greatest shoot height, number of roots per plant, root length, number of stolons per plant, daughter ramets per stolon, relative water content, cuticle thickness, and root and shoot biomasses were achieved with the MC supplementation. The improved parameters were associated with a higher silicon content of roots and shoots of the MC-treated plants. Leaf concentrations of hydrogen peroxide and abscisic acid were reduced by the MC. This effect was accompanied by enhanced activity of superoxide dismutase and catalase. The phenolic profile showed upregulation of p-hydroxybenzoic acid, vanillic acid, gallic acid, syringic acid, and ellagic acid derivative 2, while kaempferol rutinoside and catechins were downregulated. Thus, silicon chelates improve growth and trigger the physiological processes that enhance free-radical-scavenging activity in strawberry plants in vivo.

The effect of mild heat stress of different frequencies on the adaptability of Drosophila melanogaster females.

In natural populations, insects regularly face an adverse impact of different natures: harsh weather swings, lack of food resources, the insecticidal treatment. We studied the effect of repeated episodes of mild heat stress of different frequencies on stress resistance of Drosophila melanogaster females. We found out that the mild heat stress (38°Ð¡, 1 hr) repeated daily within 2 weeks resulted in (a) an increased activity of the dopamine (DA) metabolism enzymes, DA-dependent arylalkylamine N-acetyltransferase and alkaline phosphatase, which suggested a decrease in DA level, and (b) an increased survival rate under acute heat stress (38°Ð¡, 4 hr). The same mild heat stress repeated weekly had no effect on these parameters.

Identification of phenolic compounds in Myricaria bracteata leaves by high-performance liquid chromatography with a diode array detector and liquid chromatography with tandem mass spectrometry

Abstract Myricaria bracteata Royle, Tamaricaceae, is a species with a wide geographic range that encompasses Eastern Europe, Western and Central Siberia, Central Asia, and the Himalayas. This plant is used in traditional folk medicine in Russia (Siberia) and in China typically as an analgesic and for the treatment of some infections and certain types of intoxication. The aim of this study was to identify phenolic constituents of the leaves of M. bracteata from two considerably distant populations. Chromatographic profiles of the leaves of M. bracteata were analyzed for the first time. Seventeen compounds, mainly methyl ethers of quercetin (isorhamnetin, rhamnazin), kaempferol (kaempferide, rhamnocitrin), and ellagic acid as well as quercetin, quercetin 3-glucoside, kaempferol, luteolin, chrysoeriol, citric acid, gallic acid, methyl gallate, ethyl gallate, and ferulic acid were identified in hydrolyzed aqueous ethanol extracts of the leaves. Flavonols and ellagic acid were the major compounds in both samples. Isorhamnetin was the main flavonoid constituent. Kaempferide and rhamnazin were also abundant in the flavonoid complex of the leaves of M. bracteata from the Altai. This study shows that M. bracteata leaves are a source of flavonoids with possible biological activities.