Foliar Application of Selenium under Nano Silicon on Artemisia annua: Effects on Yield, Antioxidant Status, Essential Oil, Artemisinin Content and Mineral Composition

Abstract

The unique biological properties of A. annua have stimulated the research on its cultivation in different regions of the world. In this study, the effect of the Se and nano-Si supply on the yield, biochemical characteristics and mineral content of A. annua was investigated. Growth stimulation and a significant increase in the antioxidant status were recorded under Se and nano-Si foliar application. A decrease in the number of essential oil components and significant changes in the essential oil amount and composition led to significant phenophase shifts: nano-Si significantly stimulated eucalyptol and artemisia ketone accumulation and decreased germacrene D production, whereas Se demonstrated the opposite effect. A joint Se and nano-Si supply significantly decreased the camphor content and increased artemisia ketone and artemisinin levels by 1.3–1.5 times. Se/Si supplementation affected the macro- and microelements content, causing either a redistribution of leaves/stems elements (Al, Li and Zn) or a significant decrease in Ca, Mg, K, B, Cu, Fe and Mn concentrations in leaves, with no signs in growth inhibition or a decrease in the photosynthetic pigments content. The biofortification of A. annua with Se singly or in combination with nano-Si resulted in the synthesis of products with a Se content of as much as approximately 16% of the daily adequate Se consumption level (ACL) when using 5 g day-1 as a spice, or 36% of ACL when using 50 mL of tea infusion (1:2, v/w). The results indicated a high possibility of Se and nano-Si application toward the regulation of A. annua growth, biochemical characteristics (including essential oil and artemisinin) and mineral content.

Effect of Foliar Sodium Selenate and Nano Selenium Supply on Biochemical Characteristics, Essential Oil Accumulation and Mineral Composition of Artemisia annua L.

“…Indeed, this phenomenon suggests the predominant role of polyphenols (TP) in the antioxidant status of A. annua roots, but the remarkable participation of the essential oil in the corresponding activity of leaves [ 15 ]. The high correlation coefficient of 0.974 detected between TP and AOA in our research ( Figure 2 ) is close to that recorded in A. annua plants grown in the Moscow region [ 14 ].…”

“…In most cases, yield increase, essential oil improvement and polyphenol accumulation were recorded. Artemisia annua plants grown in the Moscow region under sodium selenate treatment revealed an antioxidant activity increase; although an insignificant increase in photosynthetic pigments accumulation and a low accumulation of essential oil [ 14 ].…”

Exogenous application of selenium and nano-selenium alleviates salt stress and improves secondary metabolites in lemon verbena under salinity stress

“…The results showed that the application of Se and N-Se improved lemon verbena leaf phenolic and flavonoid compounds under salinity stress conditions and thus increased its antioxidant capacity. The use of Se treatments in Ocimum basilicum L. 49 , Artemisia annua 17 and Brassica Juncea (Handa et a, 2019) plants has increased the phenolic compounds, flavonoids, and anthocyanins, which is consistent with the results of the present research. These results may be related to the phenylalanine ammonia-lyase (PAL) activity, a key enzyme in the biosynthesis of phenolic compounds in plants 18 .…”

“…In another study, the application of 2 µM in nutrient solution and 5 µM Se foliar application significantly increased the production of the essential oil, hydroxycinnamic acids, phenolic compounds, and antioxidant activity of basil leaves 49 . Moreover, it is reported that Se treatments stimulated the biosynthesis of secondary metabolites in some species under environmental stress conditions 17 , 18 . Although the mechanism of selenium's action on plants' secondary metabolites is not well known, Se treatment may changes the expression of some specific genes related to the biosynthesis of secondary metabolites in plants 46 .…”

Effect of Foliar Application of Sodium Selenate on Mineral Relationships in Brassicaceae Crops

“…In this respect, a previous investigation of the Se-Si-Cd relationship in Chinese cabbage revealed the importance of Si/Se antioxidant defense improvement for alleviating Cd stress, with a Taking into account the relative stability of the Si levels under Se supply (Table 5), it may be assumed that the differences in the ability of Brassica oleracea plants to accumulate Se depend on the initial content of Si. The previously recorded increase of Se content in the chervil, fortified with Se under Si inorganic forms and nano Si supply [21,51,52], may be attributed to Si-micro-dose growth stimulation, which did not affect plant Si concentrations. However, the possible connection of this phenomenon with the well-known protective effect of Si against environmental stresses [53] needs further investigation.…”