Stevia rebaudiana Bertoni (Asteraceae; 2n=2x=22) es una especie de valor económico que se reproduce por semillas y esquejes. Tiene flores hermafroditas de 7 mm de longitud y, alto porcentaje de ...alogamia debido a un sistema de autoincompatibilidad esporofítica. En 2013, y con fines de mejoramiento genético, se formó una colección de trabajo en la EEA INTA Famaillá, con introducciones provenientes de campos de productores de cuatro provincias: Tucumán, Jujuy, Misiones y Formosa. Dada la escasa y controvertida información disponible sobre la biología reproductiva de esta especie -y como parte de un proyecto mayoren 56 plantas individuales se determinó la ploidía mediante el recuento de cromosomas en células de ápices radicales o de cloroplastos en células oclusivas de estomas; todas ellas fueron diploides. En tres años consecutivos se realizaron cruzamientos manuales en forma aleatoria entre 30 plantas con alta viabilidad de polen y se estudiaron, por microscopía de fluorescencia, las relaciones polen-estigma/estilo en pistilos polinizados. En 156 de 168 combinaciones genotípicas se observaron granos de polen germinados sobre el estigma que no penetraban en el mismo (incompatibles) y en 12 se observaron algunos tubos polínicos que llegaban al ovario (compatibles). La incompatibilidad observada puede deberse a la expresión de autoincompatibilidad esporofítica o de incompatibilidad cruzada. A pesar de la fuerte incompatibilidad detectada, es posible planificar cruzamientos dirigidos con fines de mejoramiento genético dentro de la colección.
Stevia rebaudiana Bertoni (2n=2x=22) (Asteraceae) es una especie herbácea, alógama, originaria de Paraguay, con reproducción sexual por semillas y asexual por estacas. Su valor económico se debe a ...glucósidos de esteviol que la industria alimenticia emplea como alternativa a los azúcares convencionales. A su vez se vislumbra como una alternativa productiva para pequeños y medianos agricultores. En 2013 se implantó en la EEA INTA Famaillá, Tucumán, una colección a campo formada por plantas provenientes de campos de productores y de la EEA INTA Cerro Azul, de la variedad "criolla", de los orígenes: Tucumán (T), Jujuy (J), Misiones (M) y Formosa (F), para evaluar su comportamiento como potenciales materiales para la obtención de cultivares comerciales. En base a cinco descriptores cuantitativos y nueve cualitativos, en 2014 y 2015 se caracterizaron morfológicamente 20 plantas de T, 20 de J, 20 de M y 15 de F. Los datos obtenidos en ambos años, se sometieron a análisis estadístico multivariado, análisis de Procrustes Generalizados y Agrupamiento Jerárquico UPGMA. En los dos años se observó una baja discriminación entre plantas de Tucumán, Jujuy y Misiones, mientras que las plantas de Formosa se separaron distintivamente del resto, lo que estaría revelando un grupo genético diferente por su origen. Esta caracterización constituye una primera aproximación al conocimiento de la colección, que deberá complementarse mediante la caracterización genética con marcadores moleculares con el fin de determinar diferentes genotipos que forman el germoplasma de la colección.
Khuluq AD, Widaryanto E, Ariffin, Nihayati E. 2022. Adaptive strategy of Stevia rebaudiana to environmental change in tropical climate based on anatomy and physiology characteristics. Biodiversitas ...23: 5710-5717. High solar radiation and air temperature are the main influencing factors for plant growth and development in tropical climates. This study's objective was to understand stevia adaptation to microclimate changes at several altitudes in tropical climates. The study was conducted in a completely randomized design with altitude differences consisting of highlands, medium lands, and lowlands with ten replicates. The results showed that stevia was exposed to temperatures above 20oC during growth in the highlands by 36.46%, and in the medium lands to lowlands by 92.85%-93.96%. Meanwhile, the temperature above 30oC in the lowlands is 17.98% highest of the others. Stevia adapts to a high temperatures by increasing stomatal density, trichomes, and photosynthesis rate. Moreover, decreasing stomata (width, aperture, open percentage), leaf thickness, palisade length, xylem diameter, conductance, and transpiration rate. Stevia in the medium lands shows good adaptability with a high photosynthesis rate, percentage of open stomata 93.15%, leaf thickness 382.56 µm, and xylem diameter 30.97 µm, which is no different from the highlands. Thus, the medium lands have the potential as a new area of stevia development in a tropical climate, considering the increasingly competitive use of agricultural land in the highlands.
The ability to synthesize Indole-3-acetic acid (IAA) is widely associated with the plant growth promoting rhizobacteria (PGPR). The present work deals with isolation and characterization of such ...bacteria from the rhizosphere of medicinal plant Stevia rebaudiana and optimization of IAA production from its isolates. The optimization of IAA production was carried out at different pH and temperature with varied carbon and nitrogen sources of culture media. Out of different isolates obtained, three of them were screened as efficient PGPRs on the basis of different plant growth promoting attributes. Isolates CA1001 and CA2004 showed better production of IAA at pH 9 (91.7 µg ml−1) and at temperature 37 °C (81.7 µg ml−1). Dextrose (1%) was found to be the best carbon source for isolate CA1001 with 104 µg ml−1 IAA production. Isolate CA 2004 showed best production of IAA 36 µg ml−1 and 34 µg ml−1 at 1.5% and 1% Beef extract as nitrogen source respectively. Isolate CA 1001 showed 32 µg ml−1 IAA production at 0.5% nicotinic acid concentration. From the current study, CA1001 and CA2004 emerged as noble alternatives for IAA production further which also resulted in root and shoot biomass generation in crop plants, hence can be further used as bio-inoculants for plant growth promotion.
Las hojas de Stevia rebaudiana contienen esteviolglicósidos, endulzantes sin calorías, empleados como edulcorante natural. Por esto se busca incrementar la productividad en términos de masa foliar ...como el contenido en los principios edulcorantes. El objetivo del trabajo fue promover la obtención de ejemplares con mayor número cromosómico y mejores características fenotípicas. Se indujo la poliploidía en plantas de S. rebaudiana mediante el tratamiento de ápices caulinares en soluciones de colchicina; éstos incluyeron seis concentraciones distintas (0,1; 0,05; 0,01; 0,005; 0,001 y 0,0005%) y tres tiempos de exposición por cada uno (1, 2 y 3 hs). Se evaluó la estabilidad de los poliploides durante tres fases diferentes de multiplicación vegetativa, se analizó el tamaño de las hojas superiores e inferiores y la altura de las plantas en los individuos diploides, triploides y tetraploides. La ploidía de estacas apicales de S. rebaudiana estuvo influenciada por la concentración de colchicina y el tiempo de exposición. Se obtuvieron plantas triploides al exponer las estacas a concentraciones de 0,01% durante 2 y 3 horas, ó 0,001% durante 1, 2 y 3 horas ó 0,0005% por 3 horas. Se obtuvieron tetraploides a concentraciones de 0,005% y exposiciones de 1, 2 y 3 horas. Las plantas triploides y tetraploides mostraron pérdida de la estabilidad de la poliploidía en sucesivos estaqueos (periodos de 30 días). El tamaño de las hojas superiores, inferiores y la altura de plantas de S. rebaudiana también fueron influenciados por la ploidía.
Stevia (Stevia rebaudiana Bertoni) is an important medicinal crop grown worldwide. Leaves of stevia contain a non-caloric sweetener, stevioside, which is used as a substitute to artificial ...sweeteners. In August 2022, symptoms of chlorosis, wilting, and root rot were observed in about 30 % of stevia plants growing at the Agricultural Station at Yuma Agricultural Center, Yuma, AZ, USA (32.7125° N, 114.7067° W). Infected plants initially showed chlorosis and wilting, and the plants eventually died with foliage remaining intact to the plant. Cross sections of the crown tissue of affected stevia plants showed necrotic tissue and a dark brown discoloration in areas of the vascular and cortical tissues. Dark brown microsclerotia were observed on stem bases and necrotic roots of the infected plants. Five symptomatic plants were sampled to isolate the pathogen. Root and crown tissues (0.5 to 1 cm) were surface disinfested with 1% sodium hypochlorite for 2 min, rinsed three times with sterile water, and plated onto potato dextrose agar (PDA). All the five isolates displayed rapid mycelial growth on PDA at 28°C with a 12-h photoperiod. The mycelia were initially hyaline and turned from gray to black after 7 days. Masses of dark spherical to oblong microsclerotia were observed after 3 days on PDA, measuring an average of 75 µm width × 114 µm length (n=30). For molecular identification, genomic DNA was extracted from mycelia and microsclerotia of a representative isolate (Yuma) using the DNeasy Plant Pro kit (Qiagen, Hilden, Germany). The internal transcribed spacer (ITS), translation elongation factor-1α (TEF-1α), calmodulin (CAL), and β-tubulin (β-TUB) regions were amplified using the primer sets, ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999), MpCalF/MpCalR (Santos et al. 2020), and T1/T22 (O'Donnell and Cigelink 1997), respectively. A BLAST search of sequences revealed 98.7 to 100% identity to Macrophomina phaseolina sequences (MK757624, KT261797, MK447823, MK447918). Both morphological and molecular characteristics confirmed the fungus as M. phaseolina (Holliday and Punithaligam 1970). Sequences were submitted in the GenBank under accession numbers OP599770 (ITS), OP690156 (TEF-1α), OP612814 (CAL), and OP690157 (β-TUB). Pathogenicity assay was performed on 9-week-old stevia plants (var. SW2267), grown in 4-inch planters in the greenhouse. The inoculum was made from a 14-day-old culture of M. phaseolina grown in conical flasks (250 ml) in potato dextrose broth at 28°C. Mycelial mats of the fungus were blended in 250 ml of sterile distilled water, filtered through four layers of cheesecloth, and then calibrated to 105 microsclerotia/ml using a hemocytometer. Twenty healthy plants were inoculated by soil drenching 50 ml of the inoculum per pot. Soil drenching using sterile distilled water was done on 5 non-inoculated control plants. Plants were maintained in the greenhouse at 28 ± 3°C with 12 h photoperiod. After 6 weeks, necrosis at the base of petioles and chlorosis of the leaves, followed by wilting were noticed on all 20 inoculated plants, whereas all the 5 control plants remained healthy. The fungus was reisolated and identified as M. phaseolina based on the morphology and sequences of ITS, TEF-1α, CAL and β-TUB regions. Although M. phaseolina has been reported earlier on stevia in NC, USA (Koehler and Shew 2018), this is a first report from AZ, USA. M. phaseolina is known to be favored by high soil temperatures (Zveibil et al. 2011), thus represents a potential threat to stevia production in AZ, USA in coming years.
In recent years, the advanced approach regarding the green synthesis of nanoparticles through biogenic methods and the use of plants secondary metabolites has been quite critical. The rate of ...reduction observed in biological methodologies is much faster compared to chemical and physical methods. Therefore, this technique is an environment-friendly and cost-efficient alternative against conventional methods, and is also suitable for large scale production. In this research, ZnS nanoparticles were synthesized using a natural sweetener glycoside in the aqueous crude extract of Stevia rebaudiana that acted as an excellent bio-reductant. The structure of synthesized ZnS nanoparticles were examined through XRD, EDAX, SEM, TEM, and FTIR. The average size of ZnS nanoparticles was found to be 8.35 nm while being highly stable and predominantly spherical. The peaks at 3414.82 cm−1, which were dedicated to the OH groups from the glucose aqueous crude extract of Stevia, were observed to be very broad and thus, the FTIR spectra confirmed the presence of glucose as a capping agent and stabilizer. The cytotoxic effects of the nanoparticles was studied against the MCF-7 cancer cell line. The IC50 values of ZnS nanopartilces and Stevia extract against MCF-7 cell line were 400 and 2000 μg/mL, respectively.
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•Stevia rebaudiana was used for the biosynthesis of ZnS nanoparticles.•The ZnS nanoparticles were characterized by XRD, SEM, TEM, and FTIR.•The average size of ZnS nanoparticles was found to be 8.35 nm.•The IC50 of ZnS nanoparticles against MCF-7 cancer cell line was 400 mg/mL.
Non-English title Reus, Franziska; Zeller, Klaus-Peter; Siehl, Hans-Ullrich ...
Chemie in unserer Zeit,
06/2016, Letnik:
50, Številka:
3
Journal Article
Recenzirano
The diterpene glycoside stevioside is the most abundant among a group of sweet steviol glycosides, present in sweetleaf (Stevia rebaudiana), which is naturally occurring in Paraguay. It has already ...been used by the Guarani Indians as a sweetener. Since 2011 such "steviosides" have an EU approval as sweeteners E 960. They taste ca. 250 times sweeter than sucrose. Meanwhile, they have got a significant recognition, not least due to their use in Coca Cola life registered . We describe the isolation of stevioside and rebaudioside A from dried leaves of the sweetleaf plant. The complete set of spectra for stevioside is reported. Based on students' laboratory work this project is a follow up of the book "Classics in Spectroscopy" by S. Berger und D. Sicker (Wiley-VCH 2009).Original Abstract: Das Diterpenglykosid Steviosid ist das haeufigste in einer Gruppe sues schmeckender Steviolglykoside, die im Sueskraut (Stevia rebaudiana) vorkommen. Es stammt aus Paraguay und wurde bereits von den Guarani-Indianern genutzt. 2011 EU-weit als Lebensmittelzusatzstoff E 960 (Suesstoff) zugelassen, schmecken diese Naturstoffe etwa 250mal sueser als Zucker (Saccharose). Sie haben inzwischen betraechtliche Bekanntheit erlangt, nicht zuletzt nach ihren Nutzung in Coca Cola life registered . Wir beschreiben die Isolierung von Steviosid und des verwandten Rebaudiosids A aus getrockneten Blaettern des Sueskrauts und dazu den kompletten Satz Spektren fuer Steviosid. Dieser Artikel gehort zur Reihe ueber die Isolierung und Spektroskopie von Naturstoffen und fust auf einer Bachelorarbeit.
Bertoni is a sweet medicinal herb that is cultivated worldwide. This study aimed to identify the genotypic responses and function of nine cultivars of
(accession numbers 1-9 from the EUSTAS Stevia ...Gene Bank) to low temperature. Plants were grown
and incubated under controlled conditions at 5° or 25°C for 1 month. Cold stress significantly decreased the maximum quantum yield of photosystem II (F
/F
) in all cultivars, which was more pronounced in cultivars 5, 6, 8, and 9. The efficiency of photosystems I and II (PI
) also declined in cold-stressed plants and was accompanied by reductions in net photosynthesis (P
), intercellular CO
(C
), water use efficiency (WUE), and chlorophyll
, chlorophyll
and carotenoid contents, more so in cultivars 5, 6, 8, and 9. Regardless of the downregulation of photosynthetic capacity, the cold stress increased water-soluble carbohydrates in all cultivars, which was accompanied by an increase in fresh leaf mass and area, more so in cultivars 5, 6, 8, and 9. Furthermore, cold stress increased the stomatal index and density, epidermal cell density, stem diameter, xylem vessel width, phloem tissue width, and number of sclerenchyma in all cultivars. Even though the nine cultivars of
had lower PSII efficiencies at low temperatures, the increase in carbohydrates and leaf mass suggests that damage to PSII is not responsible for the reduction in its efficiency.
En México la prevalencia de obesidad en población adulta es superior al 70 %, en particular el estado de Veracruz tiene una de las mayores prevalencias de sobrepeso y obesidad. El consumo de azúcar ...contribuye al desarrollo de estas enfermedades. Como alternativa los edulcorantes de Stevia rebaudiana (estevia), tienen gran aceptación. El diseño y validación de los instrumentos para recabar información sobre la estevia y sus productos es importante para reducir errores de los datos obtenidos. El objetivo de este trabajo fue diseñar y validar un instrumento sobre el uso y consumo de estevia en la zona conurbada Veracruz-Boca del Rio. Se generó una encuesta inicial con 10 preguntas sobre el consumo y el conocimiento general de la población sobre estevia, cuya validación se realizó por 18 expertos que evaluaron la validez y fiabilidad de cada pregunta. Finalmente, se realizó una prueba inicial de desempeño (n=100) de la encuesta. De los encuestados, 88 % conoce de las propiedades atribuidas a estevia, 69 % padece alguna enfermedad relacionada con el consumo de azúcar y la mayoría percibió beneficios con el consumo de la planta. Se probó el desempeño de un instrumento sobre el uso y consumo de estevia que podría aplicarse a otras áreas urbanas. DOI: https://doi.org/10.54167/tch.v18i2.1392
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