Browsing by Author "Morales-Tapia, Pablo"

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    Control of shoot-tip necrosis during Argylia radiata in vitro multiplication
    (2022) Morales-Tapia, Pablo; Gambardella, Marina
    Argylia radiata is an herbaceous perennial plant native to northern Chile and a representative species of the "Blooming Desert". Due to its showy flowers and other morphological characteristics, A. radiata has great ornamental potential. In earlier work, a deep morpho-anatomical description was made, but the micropropagation protocols, which could be used for commercial purposes, are not known. Previous assays showed that cytokinin supplementation improves the multiplication rate but produces shoot-tip necrosis in the microplants. To avoid it, different modifications of the growth medium were tested, including calcium nitrate supplementation; increasing in agar concentration; indole-3-butyric acid enrichment; and change of the basal medium formulation. The effect of these changes over the damage level, number of shoots, multiplication rate, plant height (cm), fresh weight and dry weight (g), and water content (%) of the microplants were evaluated. The use of McCown Woody Plant formulation as basal medium showed the best effect, reducing the damage level and improving the multiplication rate. Additionally, IBA supplementation was effective in reducing necrotic damage. However, 0.1 mg L-1 of IBA significantly decreased the multiplication rate, while 0.01 mg L-1 led to a higher multiplication rate than that of plants grown in the control medium. In conclusion, the use of McCown Woody Plant medium and IBA supplementation should be considered in commercial A. radiata micropropagation.
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    Micropropagation of Nolana intonsa as a tool for its domestication and conservation
    (2024) Morales-Tapia, Pablo; Hepp, Josefina; Nassar, Daniel Alvaro Villegas; Takasaki, Alexis Kooichi Vidal
    A complete protocol of Nolana intonsa I. M. Johnst, micropropagation was developed. The culture media used were WPM, DKW, and MS as control. DKW medium produced the best results over in vitro development of N. intonsa , generating a significant increase in the multiplication rate, lateral shoots formation, height, and general quality of the plantlets. In the case of fresh weight, dry weight, and water content, no differences were observed between MS and DKW, but a significant decrease in these parameters was produced when the WPM medium was used. Subsequently, when DKW was defined as basal medium, the effect of auxin supplementation was also evaluated. The addition of IBA generated a desirable effect over the in vitro plantlets. The addition of 0.05 mg L -1 of IBA improve the multiplication rate, the shoot's development, plant's height, and reduced in a significant way the damage to the plantlets. Fresh weight, dry weight, and water contents also showed a significant increase when IBA supplementation was added to the DKW medium. The plants where acclimatization of the plantlets was possible, obtaining finished pot plants capable of growth under greenhouse conditions. The development of a micropropagation protocol of N. intonsa could help the conservation and sustainable utilization of this endemic Chilean species.
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    Polyphenolic Composition and Antioxidant Activity (ORAC, EPR and Cellular) of Different Extracts of Argylia radiata Vitroplants and Natural Roots
    (2022) Giordano, Ady; Morales-Tapia, Pablo; Moncada-Basualto, Mauricio; Pozo-Martinez, Josue; Olea-Azar, Claudio; Nesic, Aleksandra; Cabrera-Barjas, Gustavo
    Plant biochemistry studies have increased in recent years due to their potential to improve human health. Argylia radiata is an extremophile plant with an interesting polyphenolic profile. However, its biomass is scarce and occasionally available. Argylia in vitro biomass was obtained from tissue culture and compared with in vivo roots regarding its polyphenolic and flavonoid content. Different solvents were used to prepare extracts from the in vitro tissue of callus and aerial plant organs and in vivo roots. UPLC-MS/MS was used to assess the chemical composition of each extract. ORAC-FL and scavenging of free radicals (DPPH and OH) methods were used to determine the antioxidant capacity of extracts. Furthermore, the biological activity of the extracts was established using the cellular antioxidant activity method. The vitroplants were a good source of polyphenols (25-68 mg GAE/100 g tissue FW), and methanol was the most efficient solvent. Eight polyphenolic compounds were identified, and their antioxidant properties were investigated by different chemical methods with EPR demonstrating its specific scavenging activity against free radicals. All extracts showed cellular dose-dependent antioxidant activity. The methanolic extract of vitroplants showed the highest cellular antioxidant activity (44.6% and 51%) at 1 and 10 mu g/mL of extract, respectively. Vitroplants of A. radiata are proposed as a biotechnological product as a source of antioxidant compounds with multiple applications.