Biodegradable nanoparticles such as chitosan nanoparticles (CSNPs) are used in sustainable agriculture since theyavoid damage to the environment;CSNPs have positive effects such as the accumulation of bioactive compou...Biodegradable nanoparticles such as chitosan nanoparticles (CSNPs) are used in sustainable agriculture since theyavoid damage to the environment;CSNPs have positive effects such as the accumulation of bioactive compoundsand increased productivity in plants. This study aimed to investigate the impact of applying CSNPs on lettuce,specifically focusing on enzymatic activity, bioactive compounds, and yield. The trial was conducted using a completelyrandomized design, incorporating CSNPs: 0, 0.05, 0.1, 0.2, 0.4, and 0.8 mg mL−1. The doses of 0.4 mg mL−1improve yields up to 24.6% increases and 0.1 mg mL−1 of CSNPs increases total phenols by 31.2% and antioxidantcapacity by 34.6%. In addition, when low concentrations of CSNPs (0.05 and 0.1 mg L−1) were applied, anincrease in catalase was determined. The CSNPs represent a good alternative to be used as a biostimulant in sustainableagriculture because they improve the yield and quality of lettuce by increasing the bioactive compounds.展开更多
The use of nanomaterials has spread and has been applied in different industries,including agriculture.Here,the possibilities presented by NMs are very varied,from the biostimulation of favorable responses,or the cont...The use of nanomaterials has spread and has been applied in different industries,including agriculture.Here,the possibilities presented by NMs are very varied,from the biostimulation of favorable responses,or the control of pests and diseases,to the monitoring of characteristics of interest with the use of nanosensors.Particularly the biostimulation of agricultural crops with the use of nanomaterials is very relevant,since from this process stress tolerance,higher content of biocompounds,etc.,can be induced.Although the positive impacts on crops are clear,there is not enough information to determine the long-term impacts,both on ecosystems and on human health.展开更多
In the last two decades, unprecedented changes have taken place in the frequency and severity of wildfires;in different regions of the world, some fires were even classified as megafires. Although there are studies ab...In the last two decades, unprecedented changes have taken place in the frequency and severity of wildfires;in different regions of the world, some fires were even classified as megafires. Although there are studies about the diverse effects of fire, which have made significant theoretical contributions, a comprehensive review of the changes in fire research is required to understand worldwide patterns, particularly in those countries where fire activity is on the rise, such is the case of Mexico. The objective of this study was to analyze the trends in the research on wildfires published in Mexico and worldwide over a 40-year timescale. For this purpose, the Web of Science database, bibliometric tools, and the keywords TI = Forest fire* OR TI = Wildfire* were used to extract as many articles as possible related to fires from 1980 to 2020, without being restricted to those studies whose title included any of the variants of the keywords. There were 8458 publications about fires in the vegetation cover, with a notable increase in the frequency of studies in the previous decade;52% of the studies were concentrated in five countries and 20% of the articles focused on the study of different aspects of the soil. Mexico ranks thirteenth in volume of scientific production and studies in the country have focused mainly on the description of the quantitative relationship between the size of the affected area and the number of occurrences in the landscape, meanwhile, studies on fires and the consequences on the biotic interactions have been little explored.展开更多
Micronutrient nanoparticles(NPs)are currently an option for chemical fertilization and biostimulation in crops.However,there is little information on the phytotoxic or biostimulatory effects of NPs at low concentratio...Micronutrient nanoparticles(NPs)are currently an option for chemical fertilization and biostimulation in crops.However,there is little information on the phytotoxic or biostimulatory effects of NPs at low concentrations of some elements,such as Zn.In this study,the effect of low concentrations of Zn oxide(ZnO)NPs on germination,growth variables,and nutritional attributes of lettuce(Lactuca sativa L.)was evaluated in comparison to Zn sulfate.Romaine lettuce seeds were treated with ZnSO_(4)^(-)×7H_(2)O and ZnO NPs at Zn molar concentrations of 1×10^(−3),5×10^(−3),1×10^(−4),5×10^(−4),1×10^(−5),5×10^(−5),1×10^(−6),and 5×10^(−6).The seeds treated with ZnSO4−at 5×10^(−6)registered the highest radicle length,73%more than the control treatment.The seeds treated with ZnSO4−at 5×10^(−3)registered the lowest values,with 50%less than the control treatment.ZnO NPs at 5×10^(−6)significantly increased content of chlorophyll A and B and total phenolics.These results indicate the possible existence of a mechanism related to the intrinsic nanoparticle properties,especially at low concentrations.展开更多
Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some ag...Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 10<sup>8</sup> spores mL<sup>-1</sup>, using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4<sup><sup>®</sup></sup>. H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg);T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m<sup>2</sup> of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.展开更多
Objective: To determinate the recovery of total polyphenolic compounds content,in vitro antioxidant activity and HPLC/ESI/MS characterization of extract from Nephelium lappaceum L.(Mexican rambutan).Methods: The rambu...Objective: To determinate the recovery of total polyphenolic compounds content,in vitro antioxidant activity and HPLC/ESI/MS characterization of extract from Nephelium lappaceum L.(Mexican rambutan).Methods: The rambutan husk extract was obtained by aqueous extraction and a polyphenolic fraction was recovered using Amberlite XAD-16. The total polyphenolic compounds content was determined by the Folin Ciocalteu and butanol-HCI methods.In vitro antioxidant activity was performed using ABTS and ferric reducing antioxidant power methods.Results: Mexican rambutan husk showed a total polyphenolic content of 582 mg/g and an evident antioxidant activity by ABTS and ferric reducing antioxidant power analysis.The HPLC/ESI/MS assay allowed the identification of 13 compounds, most of which belong to ellagitannins. Geraniin, corilagin and ellagic acid were present in the sample;the mineral composition was also evaluated.Conclusions: Rambutan husk cultivated in Mexico is a promising source for the recovery of added value bioactive compounds with antioxidant activity, which have potential applications as bioactive antioxidant agents for the treatment of diseases.展开更多
Increased plant tolerance to stress may be chemically induced with applications of salicylic acid (SA). The aim of this study was to determine the change in the SA leaf concentration over time in response to the SA sp...Increased plant tolerance to stress may be chemically induced with applications of salicylic acid (SA). The aim of this study was to determine the change in the SA leaf concentration over time in response to the SA spraying in leaves of greenhouse grown tomato. In sprayed leaves the SA concentration showed changes over time similar to the reported responses to environmental stress. Two days after the first application, the SA foliar concentration reached the maximum of 8 μg·g-1, equivalent to twice the amount observed in the control plants. SA decreased until it reached the level of control plants eight days later. A second application showed actually the same response, but with a faster decline of SA in two days. According to the results of this assay, SA applications on tomato should be performed within a minimum interval of eight days in order to maintain the SA concentration related with the increase in plant tolerance to environmental stress.展开更多
The metabolic activity of the fruits continues even after harvest,which results in the loss of bioactive compounds,a decrease in the quality of the fruits,softening and browning,among other negative effects.The use of...The metabolic activity of the fruits continues even after harvest,which results in the loss of bioactive compounds,a decrease in the quality of the fruits,softening and browning,among other negative effects.The use of certain elements such as silicon can improve postharvest quality,since it is involved in the metabolic,physiological and structural activity of plants,moreover can increase the quality of the fruits.In addition,nanotechnology has had a positive impact on crop yield,nutritional value,fruit quality and can improve antioxidant activity.For these reasons,the use of beneficial elements such as silicon in the form of nanoparticles can be a viable option to improve the characteristics of the fruits.In the present study was evaluated the application of potassium silicate(125,250 and 500 mg L^(−1))and SiO_(2) nanoparticles(125,250 and 500 mg L^(−1))during the development of the crop.The results showed that the application of silicon(potassium silicate and silicon nanoparticles)increased the content of total soluble solids(up to 15.6%higher than control),titratable acidity(up to 38.8%higher than control),vitamin C(up to 78.2%higher than control),phenols(up to 22%higher than control),flavonoids(up to 64.6%higher than control),and antioxidant activity in lipophilic compounds(up to 56.2%higher than control).This study suggests that the use of silicon can be a good option to increase the content of bioactive compounds in cucumber fruits when they are applied during the development of the crop.展开更多
A new, rapid and efficient reverse phase Liquid Chromatography (RP-LC) method was developed for determination of Gibberellin A4 (GA4) in samples of flower stalk of Dasylirion cedrosanum and vegetative tissue of Epithe...A new, rapid and efficient reverse phase Liquid Chromatography (RP-LC) method was developed for determination of Gibberellin A4 (GA4) in samples of flower stalk of Dasylirion cedrosanum and vegetative tissue of Epithelantha micromeris. Purification of GA4 was carried out by solid phase extraction (SPE), in Epithelantha micromeris. In the chromatography method was obtaining a retention time of 2.1 min, using Hypersil GOLD C-18 column (100 × 4.6 mm dim and size particle 5 μ), mobile phase 50/50 acetonitrile/water and a flow 1.0 ml/min. Detection was carried out by a UV detector set at 205 nm, and a quantization limit of 0.4 mg/L. The obtained correlation coefficient was 0.995.展开更多
Euplatypus segnis is an insect pest of economic importance in pecan (Carya illinoensis) trees grown at Parras, General Cepeda and Torreón Coahuila, Mexico. The objectives in this study-were to identify the fungal...Euplatypus segnis is an insect pest of economic importance in pecan (Carya illinoensis) trees grown at Parras, General Cepeda and Torreón Coahuila, Mexico. The objectives in this study-were to identify the fungal strains associated to ambrosia borer body and diseased pecan wood and determine their pathogenicity. The results showed that the associated fungi to Euplatypus segnis and damaging the pecan wood were identified as: Helminthosporium sp., Aspergillus sp., Penicillium sp., Phoma sp., Ascochyta sp., Phaecylomices sp., Umbeliopsis sp., Torula sp., Fusarium solani, Alternaria alternata, Fusarum oxysporum, and Lasiodiplodia theobromae. The pathogenicity tests on healthy 3 year old pecan trees cv. western using Fusarium oxysporum, Fusarium solani, Alternaria alternata and Lasiodiplodia theobromae suspension conidia shown die back tree branches after 84 days inoculation. The insect in combination with the fungal invasion eventually cause the death of trees. Additionally, the insect contributes to the spread of fungi in pecan nut orchards.展开更多
Polyembryony in maize(PEm)contributes to improving the nutritional properties of the grain,as well as an increase in yield,since it generates multiple plants per seed,opening the possibility of developing new varietie...Polyembryony in maize(PEm)contributes to improving the nutritional properties of the grain,as well as an increase in yield,since it generates multiple plants per seed,opening the possibility of developing new varieties.However,it is unknown whether polyembryony in maize is the product of chromosomal abnormalities.Based on the above,in this research a cytogenetic study was proposed to verify if chromosomal abnormalities are related to the maize polyembryony.For a meiotic study,maize genotypes with variable proportions of polyembryony(PEm),from the UA-IMM-BAP population and non-PEm(monoembryonic)maize were used,while for a mitosis analysis,30 families of maternal half-siblings(MHS)from two different populations with high polyembryony,denominated as BHP(brachytic,high polyembryony)and NHP(normal height,high polyembryony)were used.All these genotypes were planted in the Buenavista Agricultural Experimental Station-UAAAN at Saltillo,Coahuila,Mexico.The frequency of PEm was estimated in all genotypes.It was found that the polyembryony occurs at frequencies from 34 to 66%in the D-02,BHP group,and from 13 to 21%in the segregating groups of the G3-0202 and G3-0201.The squash technique was used for both cytogenetic analyses.Different meiotic irregularities in maize chromosomes were detected,such as irregular association of 10%of chromosomes in metaphase 1,and agglomeration of chromatin in 100%of the cells.In addition,pollen viability was estimated by the staining technique with 1%acetocarmine dye,and it was found that the polyembryonic ones have pollen viability of 100%.In meiosis in prophase,I sub-phase diakinesis,ten pairs of bivalents were confirmed,confirming 2n=20,both in non-PEm and PEm maize,corroborating mating,and balanced segregation,without the presence of univalent or multivalent.In the chromosomal count carried out in cells in mitosis,only in the BHP-200 polyembryonic family was registered two out of twenty triploid plants.This condition of ploidy is atypical in maize,so it is recommended to analyze more plants from this family.展开更多
The tomato(Solanum lycopersicum L.)is one of the world’s most important vegetable crops.Still,phytopathogenic bacteria affect the yield and quality of tomato cultivation,like Agrobacterium tumefeciens(At),Clavibacter...The tomato(Solanum lycopersicum L.)is one of the world’s most important vegetable crops.Still,phytopathogenic bacteria affect the yield and quality of tomato cultivation,like Agrobacterium tumefeciens(At),Clavibacter michiganensis subsp.michiganensis(Cmm),Pseudomonas syringae pv.tomato(Pst),Ralstonia solanacearum(Rs),and Xanthomonas axonopodis(Xa).Synthetic chemical products are used mostly on disease plant control,but overuse generates resistance to bacterial control.This study aimed to evaluate the in vitro antibacterial activity of the ethanolic extract of Moringa oleifera Lam.leaves against At,Cmm,Pst,Rs,and Xa,as well as information about this plant species’chemical composition.Antibacterial activity against pathogens observed by microplate technique,phytochemical screening,and FTIR analysis revealed different bio-active compounds on ethanolic extracts with antibacterial activity.The growth inhibition rate ranged between 0.08%and 99.94%.The inhibitory concentration,IC50,required to inhibit 50%of At,Cmm,Pst,Rs,and Xa bacterial growth,was 276.67,350.48,277.85,351.49,and 283.22 mg/L,respectively.Inhibition of phytopathogen bacteria’s growth increased as the concentrations of the extract also increased.Moringa oleifera extract can be recommended as a potent bio-bactericide.展开更多
An alternative to the use of chemical fungicides is to enhance the defensive response of plants by appropriate stimulation, a phenomenon known as induction of resistance. The aim of this study was to determine the cha...An alternative to the use of chemical fungicides is to enhance the defensive response of plants by appropriate stimulation, a phenomenon known as induction of resistance. The aim of this study was to determine the changes of endogen levels of salicylic acid (SA) and jasmonic acid (JA) in potato plants as response to foliar application of biotic and abiotic inductors. Treatments T1 = Best Ultra F (Bacillus spp. 108 cfu/mL and Pseudomonas fluorescens 108 cfu/mL) 0.5%, T2 = FullKover HF (microbial jasmonic acid 1500 ppm) 0.2%, T3 = T1 0.5% + T2 0.1%, T4 = Milor® (Chlorothalonil + Metalaxyl) 0.5% and T5 = control (water) were applied in potato plants. The application of biotic and abiotic inductors improved the SA and JA production in potato plants. The production of salicylic acid in potato plants was observed by application of Bacillus spp. and Pseudomonas fluorescens (T1) and fungicide Milor® (T4). The application of T1 Best Ultra F, T2 FullKover HF (microbial JA), T3 (T1 + T2) and T4 Milor® improved the JA production in potato plants.展开更多
Tomato is one the most important vegetables worldwide and mineral nutrition in tomato crops is considered as the second most important factor in crop management after water availability. Mathematical modeling techniqu...Tomato is one the most important vegetables worldwide and mineral nutrition in tomato crops is considered as the second most important factor in crop management after water availability. Mathematical modeling techniques allow us to design strategies for nutrition management. In order to generate the necessary information to validate and calibrate a dynamic growth model, two tomato crop cycles were developed. Several mineral analyses were performed during crop development to determine the behavior of N, P, K, Ca, Mg and S in different organs of the plant. Regression models were generated to mimic the behavior of minerals in tomato plants and they were included in the model in order to simulate their dynamic behavior. The results of this experiments showed that the growth model adequately simulates leaf and fruit weight (EF > 0.95 and Index > 0.95). As for harvested fruits and harvested leaves, the simulation was less efficient (EF < 0.90 and Index < 0.90). Simulation of minerals was suitable for N, P, K and S as both, the EF and the Index, had higher values than 0.95. In the case of Ca and Mg, simulations showed indices below 0.90. These models can be used for planning crop management and to design more appropriate fertilization strategies.展开更多
During the production of petroleum and gas a by-product, known as congenital water, is obtained, which varies in composition depending on the geological formation from which it is extracted. In the industrial process ...During the production of petroleum and gas a by-product, known as congenital water, is obtained, which varies in composition depending on the geological formation from which it is extracted. In the industrial process its composition is modified and then it is known as “produced water”. These waters can contain high concentrations of mineral salts that can potentially be used for crop fertilization. The aim of this study was to evaluate the effects of the application of produced water on the mineral contents of the plants and levels of BTEX and TPH in the fruits of greenhouse tomato cultivation. The produced waters used were derived from gas producing zone of Sabinas-Piedras Negras in northern Mexico. These waters were analyzed according to NOM-143-SEMARNAT-2003. Waters from three different stations, (Buena Suerte, Forasteros and Monclova 1), were mixed with fresh water to obtain the treatment waters used. As a control, we used a complete Steiner solution. The results showed that the produced waters modified the absorption of essential minerals in tomato plants;it was observed that the mineral concentration in plant tissues was highest in the control plants, except for Na, in which the plants irrigated with produced water had the highest concentrations. The treatments with produced waters also affected negatively the root length, leaf dry weight, stem dry weight, number of fruits per plant, and the dry weight of the fruits.展开更多
The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, thi...The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, this was used as an inert material, on the phenolic content, antioxidant capacity and total soluble solids of bell peppers (Capsicum annuum L.). The 12 mixtures formulated, with eight replications, were distributed in a completely randomized design. Data were statistically analyzed by analysis of variance and means were compared by test Tukey<sub>5%</sub>. All variables were significantly affected (p ≤ 0.001). Fruits with highest phenolic content were developed in the mixtures M2, M5 and M6 with 538.76, 541.54 and 565.04 mg GAE·100 kg<sup>-1</sup> DW, respectively. Antioxidant capacity of fruits was increased with mixtures M2, M5, M6 and M7 with values of 934.48, 942.04, 921.69 and 924.17 μM TEAC·g<sup>-1</sup> DW, respectively. The soluble solids content was higher in mixtures M1 and M2 with values of 4.93 and 4.97 °Brix, respectively. It was concluded that the variables studied were favored when applying, as sources of fertilization, mixtures of these organic manures with river sand, which could represent a suitable alternative for food production with quality nutraceutical.展开更多
Symptoms of Tar Spot Complex (TSC) in corn appear in the form of black spots surrounded by a chlorotic halo known as fish-eye. The crop with these symptoms was found at San Pablo Autopan, Estado de Mexico. The stromal...Symptoms of Tar Spot Complex (TSC) in corn appear in the form of black spots surrounded by a chlorotic halo known as fish-eye. The crop with these symptoms was found at San Pablo Autopan, Estado de Mexico. The stromal region of foliar lesions was cut longitudinally, showing perithecia, asci and ascospores typical of Phyllachora maydis. The results were confirmed by PCR-ITS with ITS 1 and ITS4 initiators, cloned by pJET, before being sequenced and compared against NCBI’s data base. Phyllachora identity was confirmed. This is the first report where TSC pathogen has been detected under conditions that had not been previously reported, for instance, at 2600 meters above the sea level.展开更多
The aims of this study are to determine the population genetic structure of Rhizoctonia solani,associated with potato,and to assess its resistance degree to pencycuron and thiabendazole fungicides.A total of 57 strain...The aims of this study are to determine the population genetic structure of Rhizoctonia solani,associated with potato,and to assess its resistance degree to pencycuron and thiabendazole fungicides.A total of 57 strains of R.Solani were isolated from different potato crop fields in Mexico,and were classified according to their anastomosis group(AG)using the polymerase chain reaction(PCR)and restriction fragment length polymorphism(RFLP)-based analysis.Then,the amplified fragments were digested with four different endonucleases(Mse I,Ava II,Mun I and Hinc II).The Repetitive Element Sequence-Based PCR(rep-PCR)technique was used to determine the genetic diversity in R.solani populations.Results obtained by PCR-RFLP showed that 81%of the isolates were identified as belonging to AG-3 group,14%to AG1-1B and 5%to AG-11 group.In response to fungicides inhibition,IC_(50)between 0.014-0.039 mg a.i./L for pencycuron,and 0.82 to 2.91 for thiabendazole were determined,This IC_(50)value showed that the resistance factor(RF)values ranged from 1.4 to 3.945 and 0.27 to 0.97,respectively;this tendency suggests that isolates are susceptible to thiabendazole.The AG groups showed a heterogeneous resistance to pencycuron and thiabendazole,being more tolerant to these fungicides AG1-1B and AG-11 groups.The genetic analysis shows a low genetic diversity among(P-value 0.3225)and within(P-value 0.3275)populations;this can indicate a clonal reproduction and little parasexual cycle among the analyzed isolations.展开更多
基金through Project A-1-S-20923 and Grant No.725753 from S.C.Ramírez Rodríguez.
文摘Biodegradable nanoparticles such as chitosan nanoparticles (CSNPs) are used in sustainable agriculture since theyavoid damage to the environment;CSNPs have positive effects such as the accumulation of bioactive compoundsand increased productivity in plants. This study aimed to investigate the impact of applying CSNPs on lettuce,specifically focusing on enzymatic activity, bioactive compounds, and yield. The trial was conducted using a completelyrandomized design, incorporating CSNPs: 0, 0.05, 0.1, 0.2, 0.4, and 0.8 mg mL−1. The doses of 0.4 mg mL−1improve yields up to 24.6% increases and 0.1 mg mL−1 of CSNPs increases total phenols by 31.2% and antioxidantcapacity by 34.6%. In addition, when low concentrations of CSNPs (0.05 and 0.1 mg L−1) were applied, anincrease in catalase was determined. The CSNPs represent a good alternative to be used as a biostimulant in sustainableagriculture because they improve the yield and quality of lettuce by increasing the bioactive compounds.
文摘The use of nanomaterials has spread and has been applied in different industries,including agriculture.Here,the possibilities presented by NMs are very varied,from the biostimulation of favorable responses,or the control of pests and diseases,to the monitoring of characteristics of interest with the use of nanosensors.Particularly the biostimulation of agricultural crops with the use of nanomaterials is very relevant,since from this process stress tolerance,higher content of biocompounds,etc.,can be induced.Although the positive impacts on crops are clear,there is not enough information to determine the long-term impacts,both on ecosystems and on human health.
文摘In the last two decades, unprecedented changes have taken place in the frequency and severity of wildfires;in different regions of the world, some fires were even classified as megafires. Although there are studies about the diverse effects of fire, which have made significant theoretical contributions, a comprehensive review of the changes in fire research is required to understand worldwide patterns, particularly in those countries where fire activity is on the rise, such is the case of Mexico. The objective of this study was to analyze the trends in the research on wildfires published in Mexico and worldwide over a 40-year timescale. For this purpose, the Web of Science database, bibliometric tools, and the keywords TI = Forest fire* OR TI = Wildfire* were used to extract as many articles as possible related to fires from 1980 to 2020, without being restricted to those studies whose title included any of the variants of the keywords. There were 8458 publications about fires in the vegetation cover, with a notable increase in the frequency of studies in the previous decade;52% of the studies were concentrated in five countries and 20% of the articles focused on the study of different aspects of the soil. Mexico ranks thirteenth in volume of scientific production and studies in the country have focused mainly on the description of the quantitative relationship between the size of the affected area and the number of occurrences in the landscape, meanwhile, studies on fires and the consequences on the biotic interactions have been little explored.
文摘Micronutrient nanoparticles(NPs)are currently an option for chemical fertilization and biostimulation in crops.However,there is little information on the phytotoxic or biostimulatory effects of NPs at low concentrations of some elements,such as Zn.In this study,the effect of low concentrations of Zn oxide(ZnO)NPs on germination,growth variables,and nutritional attributes of lettuce(Lactuca sativa L.)was evaluated in comparison to Zn sulfate.Romaine lettuce seeds were treated with ZnSO_(4)^(-)×7H_(2)O and ZnO NPs at Zn molar concentrations of 1×10^(−3),5×10^(−3),1×10^(−4),5×10^(−4),1×10^(−5),5×10^(−5),1×10^(−6),and 5×10^(−6).The seeds treated with ZnSO4−at 5×10^(−6)registered the highest radicle length,73%more than the control treatment.The seeds treated with ZnSO4−at 5×10^(−3)registered the lowest values,with 50%less than the control treatment.ZnO NPs at 5×10^(−6)significantly increased content of chlorophyll A and B and total phenolics.These results indicate the possible existence of a mechanism related to the intrinsic nanoparticle properties,especially at low concentrations.
文摘Maize is the main crop for Mexicans;however, it is affected by species of fungi causing ear rot. This research aimed to evaluate the effect of T. asperellum T11, T. harzianum T1 4 y T. longibrachiatum T1 40 on some agronomic variables of four maize genotypes. The seeds of the genotypes H-515, Zapata 7, and H-507 were treated with a suspension of Trichoderma spp. to 1 × 10<sup>8</sup> spores mL<sup>-1</sup>, using a control (untreated seed), and Benomyl as chemical control. The planting was in Morelos, in a completely random block design with a factorial arrangement. The ear rot was natural. Data were obtained at the end of the crop cycle and processed in SAS 9.4<sup><sup>®</sup></sup>. H-515 genotype had the greatest effect on the treatment of maize seeds with Trichoderma spp. (5.562 kg);T. asperellum T11 was the strain that stood out with a mean yield of 50 ears in an area of 16 m<sup>2</sup> of 4.904 kg, and control of 4.448 kg. Our results are an economic option for farmers to contemplate the use of Trichoderma and obtain its benefits.
文摘Objective: To determinate the recovery of total polyphenolic compounds content,in vitro antioxidant activity and HPLC/ESI/MS characterization of extract from Nephelium lappaceum L.(Mexican rambutan).Methods: The rambutan husk extract was obtained by aqueous extraction and a polyphenolic fraction was recovered using Amberlite XAD-16. The total polyphenolic compounds content was determined by the Folin Ciocalteu and butanol-HCI methods.In vitro antioxidant activity was performed using ABTS and ferric reducing antioxidant power methods.Results: Mexican rambutan husk showed a total polyphenolic content of 582 mg/g and an evident antioxidant activity by ABTS and ferric reducing antioxidant power analysis.The HPLC/ESI/MS assay allowed the identification of 13 compounds, most of which belong to ellagitannins. Geraniin, corilagin and ellagic acid were present in the sample;the mineral composition was also evaluated.Conclusions: Rambutan husk cultivated in Mexico is a promising source for the recovery of added value bioactive compounds with antioxidant activity, which have potential applications as bioactive antioxidant agents for the treatment of diseases.
文摘Increased plant tolerance to stress may be chemically induced with applications of salicylic acid (SA). The aim of this study was to determine the change in the SA leaf concentration over time in response to the SA spraying in leaves of greenhouse grown tomato. In sprayed leaves the SA concentration showed changes over time similar to the reported responses to environmental stress. Two days after the first application, the SA foliar concentration reached the maximum of 8 μg·g-1, equivalent to twice the amount observed in the control plants. SA decreased until it reached the level of control plants eight days later. A second application showed actually the same response, but with a faster decline of SA in two days. According to the results of this assay, SA applications on tomato should be performed within a minimum interval of eight days in order to maintain the SA concentration related with the increase in plant tolerance to environmental stress.
文摘The metabolic activity of the fruits continues even after harvest,which results in the loss of bioactive compounds,a decrease in the quality of the fruits,softening and browning,among other negative effects.The use of certain elements such as silicon can improve postharvest quality,since it is involved in the metabolic,physiological and structural activity of plants,moreover can increase the quality of the fruits.In addition,nanotechnology has had a positive impact on crop yield,nutritional value,fruit quality and can improve antioxidant activity.For these reasons,the use of beneficial elements such as silicon in the form of nanoparticles can be a viable option to improve the characteristics of the fruits.In the present study was evaluated the application of potassium silicate(125,250 and 500 mg L^(−1))and SiO_(2) nanoparticles(125,250 and 500 mg L^(−1))during the development of the crop.The results showed that the application of silicon(potassium silicate and silicon nanoparticles)increased the content of total soluble solids(up to 15.6%higher than control),titratable acidity(up to 38.8%higher than control),vitamin C(up to 78.2%higher than control),phenols(up to 22%higher than control),flavonoids(up to 64.6%higher than control),and antioxidant activity in lipophilic compounds(up to 56.2%higher than control).This study suggests that the use of silicon can be a good option to increase the content of bioactive compounds in cucumber fruits when they are applied during the development of the crop.
文摘A new, rapid and efficient reverse phase Liquid Chromatography (RP-LC) method was developed for determination of Gibberellin A4 (GA4) in samples of flower stalk of Dasylirion cedrosanum and vegetative tissue of Epithelantha micromeris. Purification of GA4 was carried out by solid phase extraction (SPE), in Epithelantha micromeris. In the chromatography method was obtaining a retention time of 2.1 min, using Hypersil GOLD C-18 column (100 × 4.6 mm dim and size particle 5 μ), mobile phase 50/50 acetonitrile/water and a flow 1.0 ml/min. Detection was carried out by a UV detector set at 205 nm, and a quantization limit of 0.4 mg/L. The obtained correlation coefficient was 0.995.
文摘Euplatypus segnis is an insect pest of economic importance in pecan (Carya illinoensis) trees grown at Parras, General Cepeda and Torreón Coahuila, Mexico. The objectives in this study-were to identify the fungal strains associated to ambrosia borer body and diseased pecan wood and determine their pathogenicity. The results showed that the associated fungi to Euplatypus segnis and damaging the pecan wood were identified as: Helminthosporium sp., Aspergillus sp., Penicillium sp., Phoma sp., Ascochyta sp., Phaecylomices sp., Umbeliopsis sp., Torula sp., Fusarium solani, Alternaria alternata, Fusarum oxysporum, and Lasiodiplodia theobromae. The pathogenicity tests on healthy 3 year old pecan trees cv. western using Fusarium oxysporum, Fusarium solani, Alternaria alternata and Lasiodiplodia theobromae suspension conidia shown die back tree branches after 84 days inoculation. The insect in combination with the fungal invasion eventually cause the death of trees. Additionally, the insect contributes to the spread of fungi in pecan nut orchards.
基金This work was financed through the Project“Identification and sequencing of DNA regions that encode for maize polyembryony.”FON.SEC.SEP-CONACYT-BASIC SCIENCE,CB-2015-256081-Z-3061.AARC appreciates the financial support from this project for her BSc studies.
文摘Polyembryony in maize(PEm)contributes to improving the nutritional properties of the grain,as well as an increase in yield,since it generates multiple plants per seed,opening the possibility of developing new varieties.However,it is unknown whether polyembryony in maize is the product of chromosomal abnormalities.Based on the above,in this research a cytogenetic study was proposed to verify if chromosomal abnormalities are related to the maize polyembryony.For a meiotic study,maize genotypes with variable proportions of polyembryony(PEm),from the UA-IMM-BAP population and non-PEm(monoembryonic)maize were used,while for a mitosis analysis,30 families of maternal half-siblings(MHS)from two different populations with high polyembryony,denominated as BHP(brachytic,high polyembryony)and NHP(normal height,high polyembryony)were used.All these genotypes were planted in the Buenavista Agricultural Experimental Station-UAAAN at Saltillo,Coahuila,Mexico.The frequency of PEm was estimated in all genotypes.It was found that the polyembryony occurs at frequencies from 34 to 66%in the D-02,BHP group,and from 13 to 21%in the segregating groups of the G3-0202 and G3-0201.The squash technique was used for both cytogenetic analyses.Different meiotic irregularities in maize chromosomes were detected,such as irregular association of 10%of chromosomes in metaphase 1,and agglomeration of chromatin in 100%of the cells.In addition,pollen viability was estimated by the staining technique with 1%acetocarmine dye,and it was found that the polyembryonic ones have pollen viability of 100%.In meiosis in prophase,I sub-phase diakinesis,ten pairs of bivalents were confirmed,confirming 2n=20,both in non-PEm and PEm maize,corroborating mating,and balanced segregation,without the presence of univalent or multivalent.In the chromosomal count carried out in cells in mitosis,only in the BHP-200 polyembryonic family was registered two out of twenty triploid plants.This condition of ploidy is atypical in maize,so it is recommended to analyze more plants from this family.
基金This work was supported by PRODEP throughthe support of the postdoctoral fellowship granted to the first author(Trade No.511-6/18-391)The authors thank the academic body of Ecología Aplicada(UAT-CA-156)for the support obtained from their researchers to conductthis investigation.
文摘The tomato(Solanum lycopersicum L.)is one of the world’s most important vegetable crops.Still,phytopathogenic bacteria affect the yield and quality of tomato cultivation,like Agrobacterium tumefeciens(At),Clavibacter michiganensis subsp.michiganensis(Cmm),Pseudomonas syringae pv.tomato(Pst),Ralstonia solanacearum(Rs),and Xanthomonas axonopodis(Xa).Synthetic chemical products are used mostly on disease plant control,but overuse generates resistance to bacterial control.This study aimed to evaluate the in vitro antibacterial activity of the ethanolic extract of Moringa oleifera Lam.leaves against At,Cmm,Pst,Rs,and Xa,as well as information about this plant species’chemical composition.Antibacterial activity against pathogens observed by microplate technique,phytochemical screening,and FTIR analysis revealed different bio-active compounds on ethanolic extracts with antibacterial activity.The growth inhibition rate ranged between 0.08%and 99.94%.The inhibitory concentration,IC50,required to inhibit 50%of At,Cmm,Pst,Rs,and Xa bacterial growth,was 276.67,350.48,277.85,351.49,and 283.22 mg/L,respectively.Inhibition of phytopathogen bacteria’s growth increased as the concentrations of the extract also increased.Moringa oleifera extract can be recommended as a potent bio-bactericide.
文摘An alternative to the use of chemical fungicides is to enhance the defensive response of plants by appropriate stimulation, a phenomenon known as induction of resistance. The aim of this study was to determine the changes of endogen levels of salicylic acid (SA) and jasmonic acid (JA) in potato plants as response to foliar application of biotic and abiotic inductors. Treatments T1 = Best Ultra F (Bacillus spp. 108 cfu/mL and Pseudomonas fluorescens 108 cfu/mL) 0.5%, T2 = FullKover HF (microbial jasmonic acid 1500 ppm) 0.2%, T3 = T1 0.5% + T2 0.1%, T4 = Milor® (Chlorothalonil + Metalaxyl) 0.5% and T5 = control (water) were applied in potato plants. The application of biotic and abiotic inductors improved the SA and JA production in potato plants. The production of salicylic acid in potato plants was observed by application of Bacillus spp. and Pseudomonas fluorescens (T1) and fungicide Milor® (T4). The application of T1 Best Ultra F, T2 FullKover HF (microbial JA), T3 (T1 + T2) and T4 Milor® improved the JA production in potato plants.
文摘Tomato is one the most important vegetables worldwide and mineral nutrition in tomato crops is considered as the second most important factor in crop management after water availability. Mathematical modeling techniques allow us to design strategies for nutrition management. In order to generate the necessary information to validate and calibrate a dynamic growth model, two tomato crop cycles were developed. Several mineral analyses were performed during crop development to determine the behavior of N, P, K, Ca, Mg and S in different organs of the plant. Regression models were generated to mimic the behavior of minerals in tomato plants and they were included in the model in order to simulate their dynamic behavior. The results of this experiments showed that the growth model adequately simulates leaf and fruit weight (EF > 0.95 and Index > 0.95). As for harvested fruits and harvested leaves, the simulation was less efficient (EF < 0.90 and Index < 0.90). Simulation of minerals was suitable for N, P, K and S as both, the EF and the Index, had higher values than 0.95. In the case of Ca and Mg, simulations showed indices below 0.90. These models can be used for planning crop management and to design more appropriate fertilization strategies.
文摘During the production of petroleum and gas a by-product, known as congenital water, is obtained, which varies in composition depending on the geological formation from which it is extracted. In the industrial process its composition is modified and then it is known as “produced water”. These waters can contain high concentrations of mineral salts that can potentially be used for crop fertilization. The aim of this study was to evaluate the effects of the application of produced water on the mineral contents of the plants and levels of BTEX and TPH in the fruits of greenhouse tomato cultivation. The produced waters used were derived from gas producing zone of Sabinas-Piedras Negras in northern Mexico. These waters were analyzed according to NOM-143-SEMARNAT-2003. Waters from three different stations, (Buena Suerte, Forasteros and Monclova 1), were mixed with fresh water to obtain the treatment waters used. As a control, we used a complete Steiner solution. The results showed that the produced waters modified the absorption of essential minerals in tomato plants;it was observed that the mineral concentration in plant tissues was highest in the control plants, except for Na, in which the plants irrigated with produced water had the highest concentrations. The treatments with produced waters also affected negatively the root length, leaf dry weight, stem dry weight, number of fruits per plant, and the dry weight of the fruits.
文摘The aim of this research was to determine the effect of three organic manures (vermicompost, simple compost, compost with gypsum) with four different levels, as sources of fertilization, and mixed with river sand, this was used as an inert material, on the phenolic content, antioxidant capacity and total soluble solids of bell peppers (Capsicum annuum L.). The 12 mixtures formulated, with eight replications, were distributed in a completely randomized design. Data were statistically analyzed by analysis of variance and means were compared by test Tukey<sub>5%</sub>. All variables were significantly affected (p ≤ 0.001). Fruits with highest phenolic content were developed in the mixtures M2, M5 and M6 with 538.76, 541.54 and 565.04 mg GAE·100 kg<sup>-1</sup> DW, respectively. Antioxidant capacity of fruits was increased with mixtures M2, M5, M6 and M7 with values of 934.48, 942.04, 921.69 and 924.17 μM TEAC·g<sup>-1</sup> DW, respectively. The soluble solids content was higher in mixtures M1 and M2 with values of 4.93 and 4.97 °Brix, respectively. It was concluded that the variables studied were favored when applying, as sources of fertilization, mixtures of these organic manures with river sand, which could represent a suitable alternative for food production with quality nutraceutical.
文摘Symptoms of Tar Spot Complex (TSC) in corn appear in the form of black spots surrounded by a chlorotic halo known as fish-eye. The crop with these symptoms was found at San Pablo Autopan, Estado de Mexico. The stromal region of foliar lesions was cut longitudinally, showing perithecia, asci and ascospores typical of Phyllachora maydis. The results were confirmed by PCR-ITS with ITS 1 and ITS4 initiators, cloned by pJET, before being sequenced and compared against NCBI’s data base. Phyllachora identity was confirmed. This is the first report where TSC pathogen has been detected under conditions that had not been previously reported, for instance, at 2600 meters above the sea level.
文摘The aims of this study are to determine the population genetic structure of Rhizoctonia solani,associated with potato,and to assess its resistance degree to pencycuron and thiabendazole fungicides.A total of 57 strains of R.Solani were isolated from different potato crop fields in Mexico,and were classified according to their anastomosis group(AG)using the polymerase chain reaction(PCR)and restriction fragment length polymorphism(RFLP)-based analysis.Then,the amplified fragments were digested with four different endonucleases(Mse I,Ava II,Mun I and Hinc II).The Repetitive Element Sequence-Based PCR(rep-PCR)technique was used to determine the genetic diversity in R.solani populations.Results obtained by PCR-RFLP showed that 81%of the isolates were identified as belonging to AG-3 group,14%to AG1-1B and 5%to AG-11 group.In response to fungicides inhibition,IC_(50)between 0.014-0.039 mg a.i./L for pencycuron,and 0.82 to 2.91 for thiabendazole were determined,This IC_(50)value showed that the resistance factor(RF)values ranged from 1.4 to 3.945 and 0.27 to 0.97,respectively;this tendency suggests that isolates are susceptible to thiabendazole.The AG groups showed a heterogeneous resistance to pencycuron and thiabendazole,being more tolerant to these fungicides AG1-1B and AG-11 groups.The genetic analysis shows a low genetic diversity among(P-value 0.3225)and within(P-value 0.3275)populations;this can indicate a clonal reproduction and little parasexual cycle among the analyzed isolations.
