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Nanotechnology (NT) can modernize agriculture with new tools that allow better nourished and protected crops. Graphene oxide (GO) is a new kind of carbon-based nanomaterial with unique structural and physicochemical properties, which is very useful for many agricultural applications. GO, the two-dimensional carbon nanoparticles, have attracted increasing attention in the last few years because these contain large amounts of functional oxygen groups; therefore, they could be used as a fertilizer carrier to slow the release rate and improve the nutrients use efficiency, which makes this material suitable for developing new slow-release fertilizers. In this study, the application of GO nanoparticles (NPs) and graphite microparticles were compared as potential promoters of tomato seed germination and seedlings growth. Concentrations of 0, 50, 100, 200, and 500 mg L–1 were applied, using distilled water and micro-size graphite as controls. GO treatments improved root growth dose-dependently by increasing the seed vigor and showing significant differences (P ≤ 0.05) between treatments applied, increasing antioxidant enzymes activities. When using the dose of 200 mg L–1 GONPs, the radicle length was stimulated (31%) compared to the control seedlings. The graphite NPs performed better than the control in all variables; however, they were surpassed by the treatments with GONPs.

La nanotecnología agrícola y ambiental tiene cientos de aplicaciones para solucionar problemas que aquejan a la sociedad día con día. No obstante, los países de América Latina han participado relativamente poco en estos avances tecnológicos, al compararlos con sus contrapartes de América del Norte, Europa o Asia. Dado lo anterior, es importante destacar que países como México, Chile y Brasil tienen avances nanotecnológicos significativos y han logrado la formación de grupos de especialistas consolidados, a pesar de las limitaciones económicas y de acceso a equipo científico que aqueja a estas naciones. En consecuencia y con base en las múltiples aplicaciones potenciales, algunas ya en comercialización, es necesario que el Estado, la industria y la comunidad científica fortalezcan e impulsen la innovación, el equipamiento y la formación de recursos humanos, así como una adecuada inversión en nanotecnología agrícola y ambiental. Asimismo, se deben considerar aspectos de normalización y regulación, tanto como estudios in silico e in vivo (en laboratorio, invernadero y campo) que valoren y evidencien los efectos nulos, secundarios o tóxicos de los nanomateriales sobre los organismos vivos y los ecosistemas.

Lippia graveolens u orégano mexicano, es una planta de importancia económica y la recolección del follaje se realiza principalmente de poblaciones naturales. La micropropagación propone una alternativa para la producción de material, con alta calidad fitosanitaria y propagación en menor tiempo de individuos seleccionados por sus características de valor comercial. El objetivo de este trabajo fue establecer un protocolo para la propagación in vitro de Lippia graveolens. La investigación se realizó en el año 2018-2019. El establecimiento se logró con segmentos nodales en medio basal MS, en esta etapa se recuperó 57.32% de explantes axénicos. Para la etapa de propagación se adicionó al medio MS cuatro concentraciones (0, 1, 2 y 3 mg L-1) de bencilaminopurina (6-BAP), se evaluó número de brotes y altura de plántula, los mejores resultados en la multiplicación se lograron con 3 mg L-1 de 6-BAP, obteniéndose 40.35 brotes por explante. La longitud de brote fue mayor en los tratamientos sin reguladores de crecimiento. Para el enraizamiento, se ensayó con tres concentraciones (0, 0.1, 0.3 y 0.5 mg L-1) de auxinas (ácido indol acético y ácido indol butírico) y se evaluó el porcentaje de enraizamiento y la longitud de la raíz obteniéndose igual resultado con y sin reguladores auxínicos. En la fase de aclimatación se evaluó el fotoperiodo (16 h y 24 h) con y sin micorrizas (Glomus intraradicens). El mejor tratamiento se obtuvo con 24 h luz y con adición de micorrizas con un 86.11% de supervivencia.

Tomato production under greenhouse conditions needs vigorous seedlings to reduce the loss of plants after the transplant. Different local substrates such as agave bagasse, pine bark and coconut fiber complemented with peat, expanded clay, vermiculite and pure peat for tomato seedlings production were tested. The seed germination, root ball compaction, height of the seedling, stem diameter, and total dry weight were quantified. The stem diameter observed in Agave - bagasse + peat + expanded - clay + vermiculite (30:60:5:5 v/v) (BMTAEV3), Agave - bagasse + pine - bark + peat + expanded - clay + vermiculite (30:30:30:5:5) (BMCPTAEV4), Agave - bagasse + peat + expanded - clay + vermiculite (50:30:10:10) (BMTAEV5), Sphagnum peat (SUNSHINE® 3) 100% (M3SC), and Agave - bagasse + peat + expanded - clay + vermiculite (40:40:10:10) (BMTAEV6) treatments were in acceptable parameter range to commercial use, but BMTAEV3, BMTAEV5, and BMTAEV6 treatments show better germination, root ball compaction, a bigger height and diameter, getting tomato seedlings with vigor to the transplant. The local substrata overcome the commercial growth medium parameters in seedlings evaluation. It is shown that mixtures of agave-bagasse with expanded clay, and vermiculite are a substrate alternative for tomato seedlings production, reducing the use of expensive and scarce material such as peat by up to between 40 and 60% (v/v). Key words: Agave by-product, parameters, substrate, transplant, tomato seedlings.

The establishment of green root cultures of Stevia rebaudiana Bertoni, and the effect of elicitors such as hydrogen peroxide (H2O2) and methyl jasmonate (MeJA), is shown in the present study. Stevioside, rebaudioside A, and the isomers steviol/isosteviol were identified through DFI-ESI-IT-MSn and UPLC-TOFMS spectrometric systems, in combination with solid-phase extraction. The accumulation of steviol glycosides increased by 2.4 times (compared to the control value of 22.35 μgSG per gDW), with the addition of 250 μM H2O2. The non-enzymatic antioxidant response, which resulted from production of phenolic and flavonoid compounds, was modified based on the elicitor and the dose used. The maximum accumulation of flavonoids was induced on the third day with the addition of H2O2 (250 or 500 μM), and with MeJA (250 or 500 μM); the increase was observed on the fifth day. The enzymatic antioxidant response of the catalase and peroxidase from the roots under elicitation confirmed the stress conditions.

Polyphenols may be an effective therapy for both the prevention and treatment of cancer. Previous studies have found that these compounds may inactive Hela cells, which may even be converted into a normal cells post-treatment. The present study extracted phenolic compounds from pomegranate peel, with the polyphenols then purified using different solvents and identified by means of high-performance liquid chromatography-tandem mass spectrometry (HPLC/MS). Once the phenolic compounds had been purified, we evaluated their cytotoxic effects on both the Hela and NIH-3T3 cell lines, on which an apoptosis assay was also carried out. Additionally, apoptosis assay was carried out on Hela and NIH-3T3. Lastly, the proteome profile was analysed via two-dimensional gel electrophoresis (2-DE) and liquid chromatography-tandem mass spectrometry (LC/MS/MS). We isolated and then purified punicalagin and ellagic acid (EA) from pomegranate peel, with both compounds likely to have a cytotoxic effect on Hela and NIH-3T3. However, this effect depends on both concentration and exposure time. Results obtained using a Cayman commercial assay kit suggests that punicalin and EA regulate the apoptosis on the Hela and NIH-3T3 cell lines. Finally, we observed that polyphenols compounds regulate the expression of proteins related to apoptosis. In conclusion, punicalin and EA have a cytotoxic effect on Hela and, furthermore, reactive the apoptotic pathway in this cell.

Zeolita clinoptilolita es un aluminosilicato hidratado que pertenece a un grupo de minerales de origen volcánico y posee propiedades agrícolas interesantes. El objetivo de este trabajo fue determinar el efecto causado por la zeolita en plántulas de tomate (Solanum lycopersicum Mill.) cultivadas en macetas. Por lo tanto, se evaluaron las propiedades físicas de tres sustratos: peat moss (pm), perlita (per) y zeolita (zeo), y sus diferentes mezclas (pm:per:zeo) en los siguientes tratamientos: (T1 o Control) = 100:0:0; T2 = 70:30:0; T3 = 70:20:10; T4 = 70:10:20 y T5 = 70:0:30 (v/v). Comparado con el tratamiento control, los sustratos conteniendo 30% de zeolita incrementaron su capacidad de retención de agua (260%), porosidad total (8.47%), densidad aparente (212%) y la densidad de partículas (230%). En comparación con las plantas desarrolladas en el sustrato control (100% peat moss), las que fueron cultivadas con 30% de zeolita incorporada al sustrato, exhibieron valores estadísticamente superiores en altura (24.2%), área foliar (64.5%), longitud de raíz (63.2%), biomasa seca aérea (62.5%), biomasa seca de raíz (208.9%), diámetro de tallo (28.5%) y número de hojas (92%); sin embargo, el índice de clorofila no mostró efectos significativos. Los resultados claramente indican que la incorporación de zeolita en los sustratos puede promover el crecimiento de las plantas de tomate.

Nanoparticles (NPs) interact with living organisms through different pathways. These interactions depend on chemical nature of NPs, capping, and size, among others. In the last years, the use of different NPs for agricultural purposes has increased. Their applications mainly involve dosing though soil or foliar spraying. Different studies have indicated that NPs can be absorbed by plant roots or through foliar exposure, and may reach all plant organs including fruits, affecting their quality. In addition, they provide a route of exposure for humans and animals. Due to their physicochemical properties and high reactivity, NPs may influence basic cellular processes such as proliferation, metabolism, and death. In recent years, several studies have evaluated the effects of NPs applications, highlighting their capability to induce oxidative stress, interrupt the transport activity of the cell membrane of electrons/ions, cause oxidative damage, or modulating gene regulation. Given that risk assessment for conventional materials may not be applicable to nanomaterials (NMs), it is of great practical and scientific importance to study the safety of NMs for sustainable food production and consumer health protection. The present review intends to consolidate current knowledge on cellular and related interactions of NPs with plants. With this information we propose what we consider are relevant gaps to be filled in order to provide a more systemic picture of the above-mentioned interactions.

La nanotecnología (NT) estudia los materiales cuyo tamaño corresponde a la escala atómica y molecular (1-100 nm), destacando como los más estudiados a las nanopartículas (NPs) metálicas y las derivadas del carbono. En lo que respecta a la agricultura moderna, los estudios relacionados a este tipo de materiales han ido avanzando y se prevé un importante crecimiento en los reportes de resultados de investigación en el área, debido a la posibilidad de incrementar con su uso, la producción de alimentos. En este sentido, la NT brinda la posibilidad de generar nanofertilizantes y promotores del crecimiento. No obstante, actualmente existen imprecisiones sobre los resultados obtenidos, por una parte, algunas investigaciones muestran que la aplicación de los nanotubos de carbono y las NPs metálicas tienen un efecto benéfico en el crecimiento de las plantas, mientras que otros trabajos reportan inhibición y fitotoxicidad. Actualmente, la demanda de alimentos básicos a nivel mundial aumenta, pero las investigaciones y productos para incrementar el rendimiento de los cultivos son aún insuficientes. Por lo tanto, una opción para el desarrollo de una agricultura sustentable pudiese ser la generación de nanoproductos. Debido a lo antes señalado, este artículo analiza recientes investigaciones relacionadas con la utilización de las NPs en la agricultura y sus usos potenciales como nanofertilizantes y promotores de crecimiento de las plantas.

La aplicación de la nanotecnología (NT) en el sector agroalimentario es uno de los campos de más rápido crecimiento en la nano-investigación. Innovar y generar tecnología para producir la cantidad y la calidad de alimentos suficientes para alimentar a una población mundial en rápido crecimiento de los tiempos modernos, siempre será el mayor desafío. El uso excesivo e indiscriminado de agroquímicos sintéticos para incrementar el rendimiento de los cultivos agrícolas conduce al deterioro de la salud del suelo, a la degra-dación de agroecosistemas, causa problemas relacionados con la contaminación del ambiente y genera resistencia a los pesticidas por insectos y microorganismos fitopatógenos. En este contexto, la NT ha surgido como un avance tecnológico que puede transformar sectores de la agricultura, proporcionando herramientas para la detección rápida de enfermedades en los cultivos, así como mejorar la capacidad de las plantas para absorber los nutrientes y crecer con mayor velocidad. Con la NT se abre un amplio abani-co de oportunidades en la agricultura para producir agroproductos como nanofertilizantes, nanopestici-das, nanoherbicidas y nanosensores, que permitirán incrementar el rendimiento de alimentos de manera sustentable y reduciendo el impacto ambiental. Se espera que esta revisión crítica pueda proporcionar la información básica sobre los antecedentes en la investigación agronano tecnológica, que permita avan-zar con la experimentación en las aplicaciones de las nanopartículas en la agricultura ecológica

The use of nanotechnologies in agricultural systems has been widely promoted. Nanomaterials have been proposed as a useful tool for the improvement of agricultural practices. Some plants have shown diverse effects in terms of morphological and physiological changes, with uptake and translocation into different parts. A relation has been demonstrated between the dose and the plant response in different crops, with variations from plant to plant. However, the use of nanoparticles for crop production still faces some challenges because of possible toxicity and hazardous effects, and especially because of the lack of experimental evidence that nanomaterials are harmless to plants and humans. Some studies have reported both positive and negative effects of nanoparticles on plant growth and development, depending on the nature of the nanomaterials, application, time of exposure, plant species, and soil characteristics. The objective of this chapter is to describe the effects of the application of nanoparticles on plant development, focusing on the physiological and biochemical mechanisms of plants in relation to nanoparticles. It also reviews the behavior of nanoparticles in the soil and water matrix and their effects on microbial communities interacting with plants.

Hamelia patens is a perennial shrub native from Mexico which is used in traditional medicine to treat chronic wounds and tumors. Bioactive monoterpenoid indole alkaloids (MIAs) and monoterpenoid oxindole alkaloids (MOAs) have been isolated from this species, associated with the ethnomedical use. In order to study the biosynthesis and production of these alkaloids, H. patens plants were treated with the stress hormone jasmonic acid. Nuclear magnetic resonance-based metabolic profiles and multivariate data analysis were applied to explore changes or variability in elicited and control plants. According to the partial least square-discriminant analysis from MeOH/H2O fractions, sucrose, tryptophan, glutamic acid, glutamine, strictosidine, p-coumaric acid, chlorogenic acid, and the MOAs isopteropodine, palmirine and pteropodine were predominant in the treated plants, while glucose, aspartic acid, acetic acid, and loganic acid concentrations were higher in control plants. HPLC analysis showed that accumulation of pteropodine, isopteropodine, speciophylline, rumberine, hameline and palmirine in elicited plants was preceded by an increase in the transcription level of 1-deoxy-d-xylulose-5-phosphate synthase (DXS, EC 2.2.1.7) and strictosidine synthase (STR, EC 4.3.3.2), and STR activity during a time course. However, no inductions of transcription and enzyme activity of strictosidine β-glucosidase (SGD, EC 3.2.1.105) were observed in elicited plants. Correlations between primary and secondary metabolism biosynthetic pathways, such as the alkaloid and chlorogenic acid biosynthesis were found. Also, their implications in the plant fitness to stress are proposed. Confirmation of tryptophan as a precursor of MIA and MOA, via shikimate pathway, was done by L-[3′-14C]-tryptophan feeding.

Plants cells sense their environment through oxidative signaling responses and make appropriate adjustments to gene expression, physiology and metabolic defense. Root cultures of Uncaria tomentosa, a native plant of the Amazon rainforest, were exposed to stressful conditions by combined addition of the glutathione inhibitor, buthionine sulfoximine (0.8 mM) and 0.2 mM jasmonic acid. This procedure induced a synchronized two-fold increase of hydrogen peroxide and guaiacol peroxidases, while the glutathione content and glutathione reductase activity were reduced. Likewise in elicited cultures, production of the antioxidant secondary metabolites, monoterpenoid oxindole and glucoindole alkaloids, were 2.1 and 5.5-fold stimulated (704.0 ± 14.9 and 845.5 ± 13.0 µg/g DW, respectively) after 12 h after, while phenols were three times increased. Upon elicitation, the activities and mRNA transcript levels of two enzymes involved in the alkaloid biosynthesis, strictosidine synthase and strictosidine β-glucosidase, were also enhanced. Differential proteome analysis performed by two-dimensional polyacrylamide gel electrophoresis of elicited and control root cultures showed that, after elicitation, several new protein spots appeared. Two of them were identified as thiol-related enzymes, namely cysteine synthase and methionine synthase. Proteins associated with antioxidant and stress responses, including two strictosidine synthase isoforms, were identified as well, together with others as caffeic acid O-methyltransferase. Our results propose that in U. tomentosa roots a signaling network involving hydrogen peroxide and jasmonate derivatives coordinately regulates the antioxidant response and secondary metabolic defense via transcriptional and protein activation.

The activity and gene expression of strictosidine-related enzymes in Uncaria tomentosa root cultures exposed to oxidative stress were studied. Elicitation with 0.2 mM hydrogen peroxide (H2 O2 ) or a combination of 0.8 mM buthionine sulfoximine and 0.2 mM jasmonic acid (BSO-JA) increased peroxidase activities by twofold at Day 8 and glutathione reductase by 1.4-fold at Day 5 in H2 O2 elicited cultures respect to the control. Production of monoterpenoid oxindole alkaloids (MOA), 3α-dihydrocadambine, and dolichantoside was stimulated after H2 O2 elicitation, reaching levels of 886.4 ± 23.6, 847.7 ± 25.4, and 87.5 ± 7.2 µg/g DW, at Day 8 which were 1.7-, 2.1-, and 2.3-fold higher relative to control. BSO-JA elicited cultures produced about twice alkaloids than H2 O2 -treated cultures, following a biphasic pattern with maxima at 0.5 and 8 days. Alkaloid production was preceded by increase in strictosidine synthase (STR) and strictosidine glucosidase (SGD) activities. After elicitation with H2 O2 or BSO-JA, the STR activity (pKat/mg protein) increased by 1.9-fold (93.8 ± 17.8 at 24 h) or 2.5-fold (102.4 ± 2.2 at 6 h) and the SGD activity (pKat/mg protein) by 2.8-fold (245.2 ± 14.4 at 6 h) or 4.2-fold (421.2 ± 1.8 at 18 h) relative to control. STR and SGD transcripts were upregulated after elicitation. H2 O2 -treated roots showed higher levels of STR at 48-192 h and SGD at 24-48 h, while BSO-JA treatments showed STR increased at 12 h and SGD at 24 h. Also, LC/ESI-MS confirmed the biosynthesis of dolichantoside from N-ω-methyltryptamine and secologanin by U. tomentosa protein extracts.

The applications that nanotechnology (NT) has on agriculture systems are diverse and promising because they have the potential to contribute in maintaining its productivity and efficiency by reducing costs and the quantity of synthetic agrochemicals employed. For instance, it is important to emphasize that by means of NT it is possible to develop encapsulated nanopesticides, stabilization of biopesticides and slow-release fertilizers. Nanoparticles of zinc oxide and silver are studied for their potential as antimicrobial, nanofertilizers and growth promoters of agricultural plants. Therefore, the aim of this study was to evaluate the effect of pure zinc oxide nanoparticles (ZnONPs) and ZnONPs with silver (ZnONPs + Ag) on growth of C. annuum plants. The sol-gel method was used to study the synthesis and characterization of NPs. Foliar application of ZnONPs to pepper plants was done manually once a week. The experimental design was completely at random with four treatments and five repetitions. Data collected were analyzed by ANOVA and Tukey's multiple range tests (p≤ 0.05). Compared to control plants without the application of ZnONPs, treatments exposed to the application of ZnONPs + Ag (2.5%), were those that had a significant higher shoot and root growth, as well greater biomass production, with higher values of height (16.8%), leaf area (30.3%), total biomass production (59.5%), root dry biomass (112.5%), stem dry biomass (76%) and root length (24.4%). As compared to control plants, those treated with ZnONPs + Ag (2.5%) reported a quantitative increase of chlorophyll index (8%) and leave number (32.6%). The biological effect of the applied NPs, could be related to the zinc activity as a precursor in the production of auxins, which in turn could promote cell division and elongation, as well by its influence on the reactivity of indol acetic acid, which acts as hormonal phytoestimulant. Also ZnONPs might be involved in the biosynthesis of cytokinins and gibberellins; as well on the induction of greater activity of antioxidant enzymes.