The First Evidence of the Beneficial Effects of Se-Supplementation on In Vitro Cultivated Olive Tree Explants

Abstract

Selenium is an essential micronutrient that provides important benefits to plants and humans. At proper concentrations, selenium increases plant growth, pollen vitality, the shelf life of fresh products, and seems to improve stress resistance; these effects can certainly be attributed to its direct and indirect antioxidant capacity. For these reasons, in the present work, the effects of selenium at different dosages on in vitro cultivated olive explants were investigated to observe possible positive effects (in terms of growth and vigor) on the proliferation phase. The work was carried out on four different olive cultivars: “San Felice”, “Canino”, “Frantoio”, and “Moraiolo”. The explants were cultured in aseptic conditions on olive medium (OM), with the addition of 4 mg·L−1 of zeatin, 30 g·L−1 of sucrose, and 7 g·L−1 of agar. The experimental scheme included a comparison between explants grown with five different concentrations of Na2SeO4 (0, 10, 20, 40, and 80 mg L−1) added to the medium during three successive subcultures. Interesting information has emerged from the results and all varieties responded to different concentrations of Selenium. The optimal Se dosages varied for each cultivar, but in general, Se concentration between 10 and 40 mg L−1 increased fresh and dry weight of the explants and shoot lengths. Se treatment induced in all cultivars and for all dosages used an increase in total Se content in proliferated explants. Furthermore, as the subcultures proceeded, the ability of the explants to absorb Se did not diminish. The Se content ranged from 8.55 to 114.21 µg kg−1 plant DW in ‘Frantoio’, from 9.83 to 94.85 µg kg−1 plant DW in ‘Moraiolo’, from 19.84 to 114.21 µg kg−1 plant DW in ‘Canino’, and from 20.97 to 95.54 µg kg−1 plant DW in ‘San Felice’. In general, the effect of selenium tends to decrease with the progress of subcultures and this suggests a sort of “adaptation” effect of the explants to its presence. The present study highlights for the first time the possibility of using in vitro cultures as biotechnological support to study supplementation with selenium and its effects on in vitro olive plant growth.

Effect of Selenium Application and Growth Stage at Harvest on Hydrophilic and Lipophilic Antioxidants in Lamb’s Lettuce (Valerianella locusta L. Laterr.)

“…The result of the positive effect of low concentrations of selenium on the growth of lamb's lettuce is consistent with previously published results for the study of different species of plants, such as spinach [23], lettuce [24], Indian mustard [25], and faba bean [26]. The phenomenon that a low concentration of selenium stimulates plant growth whereas a high concentration of selenium has a toxic effect is regarded as hormesis and was proven for selenium in many previous studies [27,28]. The toxic effect of high concentrations of selenium is well studied and is usually associated with the inclusion of selenium instead of sulfur in amino acids and peptides and with the induction of oxidative and nitrosative stresses by selenium, which leads to metabolic disorders and damage to cellular structures [29].…”

Pomegranate trees quality under drought conditions using potassium silicate, nanosilver, and selenium spray with valorization of peels as fungicide extracts

“…The application of selenium at five different concentrations at 0, 10, 20, 40, and 80 mg L −1 on four different olive cultivars: “San Felice”, “Canino”, “Frantoio”, and “Moraiolo”. It was noticed that Se concentration between 10 and 40 mg L −1 increased fresh and dry weight of the explants and shoot lengths 71 .…”

Zinc Oxide Nanoparticles and Fe-Modified Activated Carbon Affecting the In Vitro Growth of Date Palm Plantlets cv. Medjool

“…Thus, it is clear that the addition of zinc oxide, specifically ZnO-NPs and AC or Fe-AC, accelerates the growth of more robust palm plantlets. Since more vigorous plantlets generate more efficient roots and have stronger growth potential, these factors are crucial for adaptation and transplanting processes under ex vitro circumstances [65].…”

“…The increase in chlorophylls is attributed to the capacity of ZnO-NPs to enhance photosynthetic efficiency by increasing chlorophyll's ability to absorb light. In particular, the mechanism causing this effect was the transfer of energy from ZnO-NPs to chlorophyll a, which in turn caused the pigment contents to increase [65].…”