Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.828
Filtrar
1.
BMC Plant Biol ; 22(1): 30, 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35027005

RESUMO

Strigolactone is a newly discovered type of plant hormone that has multiple roles in modulating plant responses to abiotic stress. Herein, we aimed to investigate the effects of exogenous GR24 (a synthetic analogue of strigolactone) on plant growth, photosynthetic characteristics, carbohydrate levels, endogenous strigolactone content and antioxidant metabolism in cucumber seedlings under low light stress. The results showed that the application of 10 µM GR24 can increase the photosynthetic efficiency and plant biomass of low light-stressed cucumber seedlings. GR24 increased the accumulation of carbohydrates and the synthesis of sucrose-related enzyme activities, enhanced antioxidant enzyme activities and antioxidant substance contents, and reduced the levels of H2O2 and MDA in cucumber seedlings under low light stress. These results indicate that exogenous GR24 might alleviate low light stress-induced growth inhibition by regulating the assimilation of carbon and antioxidants and endogenous strigolactone contents, thereby enhancing the tolerance of cucumber seedlings to low light stress.


Assuntos
Adaptação Ocular/efeitos dos fármacos , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/metabolismo , Compostos Heterocíclicos com 3 Anéis/metabolismo , Lactonas/metabolismo , Produtos Agrícolas/efeitos dos fármacos , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo
2.
J Hazard Mater ; 423(Pt B): 127114, 2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-34537638

RESUMO

Although selenium (Se) is an essential microelement for humans and animals, it is a potentially toxic element due to its bioaccumulation potential. In this study, Se fertilizer was supplied in a greenhouse vegetable (cucumber) plantation using an innovative system consisting of nanobubbles (NB_Se) and compared to that under conventional conditions of fertigation (C_Se) with six doses. The results revealed that NB_Se significantly reduced soil Se accumulation (38%-144%) and increased cucumber Se content compared with the C_Se treatments at the same Se dose. NB_Se significantly lowered the soil bacterial diversity, with an initial increase and then decrease with the Se doses. Bacterial associations and potential keystone taxa also differed between the NB_Se and C_Se. The greater abundance of oxidizing bacteria (indicated by the function composition of bacterial community) and the improved soil redox environment created by NBs sustained more available Se for plants, leading to a reduction in soil Se residual and an increase in the plant Se content. Our results highlight the feasibility and efficiency of NB_Se and demonstrate the important implications of Se for the maintenance of soil health and sustainability.


Assuntos
Cucumis sativus , Selênio , Animais , Bactérias/genética , Fertilizantes/análise , Humanos , Solo
3.
Food Chem ; 369: 130969, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34500206

RESUMO

Modified atmosphere packaging (MAP) can inhibit microbial growth and prolong shelf life of fresh-cut cucumbers. This study compared the effects of different packaging gases on the growth of E. coli O157:H7 and sensory characteristics of fresh-cut cucumbers. Changes in key movement, adhesion, and oxidative stress genes expression of strain under optimal MAP and air were determined. Cell population density, the extracellular carbohydrate complex content and expression of curli fimbriae were evaluated. Results revealed that the growth of E. coli O157:H7 in fresh-cut cucumbers could be effectively inhibited under MAP (atmosphere = 2% O2, 7% CO2, 91% N2), and better maintained the sensory characteristics. Furthermore, the inhibition mechanism was revealed by inhibiting the expression of movement (fliC), adhesion (eaeA) and oxidative stress (rpoS and sodB) genes in E. coli O157:H7, reducing biofilm formation, extracellular carbohydrate production and curli fimbriae expression. Proper MAP can maintain the quality and safety of fresh-cut cucumbers.


Assuntos
Cucumis sativus , Escherichia coli O157 , Atmosfera , Contagem de Colônia Microbiana , Cucumis sativus/genética , Escherichia coli O157/genética , Microbiologia de Alimentos , Embalagem de Alimentos
4.
Food Chem ; 369: 130960, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34500210

RESUMO

Pesticides and fertilizers are often used to improve the yield and quality of cucumber fruit. In this study, the effect of pesticide applied with or without foliar fertilizer on the cucumber fruit metabolism was investigated. The results showed that the mixed use of pesticides and foliar fertilizer could significantly increase the contents of organic acids and the antioxidant level. When pesticide was used without foliar fertilizer, cucumber fruit up-regulated (1.3 times) shikimate-phenylpropanoid pathway and improved the antioxidant capacity to deal with the pesticide stress. However, the tricarboxylic acid cycle was up-regulated 1.1 times and the antioxidant capacity was improved to promote the pesticide dissipation when pesticide was applied with foliar fertilizer. These observations indicate that the mixed application of foliar fertilizer and pesticides can regulate related metabolites and metabolic pathways, improve the quality and antioxidant capacity of cucumber fruit, and promote the dissipation of pesticides.


Assuntos
Cucumis sativus , Praguicidas , Cromatografia Líquida de Alta Pressão , Fertilizantes/análise , Frutas/química , Metabolômica , Praguicidas/análise
5.
Sci Total Environ ; 804: 150233, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34520920

RESUMO

Understanding about the influence of biochar colloidal and nanoscale particles on plant is limited. We therefore extracted the colloids and nanoparticles from hot pepper stalk biochar (CB600 and NB600), and examined physiological responses of cucumber early seedlings through hydroponic culture and pot experiment. CB600 had no significant effect on shoot at 500 mg/L, while it decreased root biomass and inhibited lateral root development. The biomass and root length, area, and tip number dramatically reduced after 500 mg/L NB600 treatment. Water content of NB600-exposed shoot was lower, suggesting water uptake and transfer might be hindered. For resisting exposure stress, root hair number and length increased. Even, the study observed swelling and hyperplasia of root hairs after direct exposure of CB600 and NB600. These adverse effects might be associated with the contact and adhesion of CB600 and NB600 with sharp edges to root surface. For a low concentration of 50 mg/L, NB600 did not influence cucumber early seedlings. In soil, CB600 and NB600 did not cause inhibitory effect at relatively high contents of 500 mg/kg and 2000 mg/kg. This study provides useful information for understanding phytotoxicity and environmental risk of biochar colloids and nanoparticles, which has significant implications with regard to biochar application safety.


Assuntos
Cucumis sativus , Nanopartículas , Carvão Vegetal/toxicidade , Coloides , Nanopartículas/toxicidade , Raízes de Plantas , Plântula , Solo
6.
Food Chem ; 367: 130667, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34339981

RESUMO

The main purpose of the present study was to investigate the effect of different fertilizers on the physicochemical properties, multi-element and volatile composition of cucumbers. All samples were divided into five groups according to different combinations and amounts of chicken manure, NPK 17-17-17 fertilizer and microbial fertilizer. The co-application of chicken manure (120,000 kg/ha) and NPK 17-17-17 fertilizer (750 kg/ha) achieved the best texture properties, whereas the addition of the microbial fertilizer at 6000 kg/ha significantly improved the color quality of cucumbers. Similarly, the co-application of chicken manure, NPK 17-17-17 fertilizer and microbial fertilizer at 6000 kg/ha enhanced the number and abundance of volatile components detected in the cucumbers. Cucumbers from the control group contained the highest levels of most of the determined elements. Overall, a combination of chicken manure, NPK 17-17-17 fertilizer and 6000 kg/ha microbial fertilizer is recommended as a relatively efficient fertilizer utilization for cucumbers.


Assuntos
Cucumis sativus , Fertilizantes , Agricultura , Fertilizantes/análise , Esterco , Solo
7.
Int J Mol Sci ; 22(24)2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34948084

RESUMO

A Raffinose family oligosaccharides (RFOs) is one of the major translocated sugars in the vascular bundle of cucumber, but little RFOs can be detected in fruits. Alpha-galactosidases (α-Gals) catalyze the first catabolism step of RFOs. Six α-Gal genes exist in a cucumber genome, but their spatial functions in fruits remain unclear. Here, we found that RFOs were highly accumulated in vascular tissues. In phloem sap, the stachyose and raffinose content was gradually decreased, whereas the content of sucrose, glucose and fructose was increased from pedicel to fruit top. Three alkaline forms instead of acid forms of α-Gals were preferentially expressed in fruit vascular tissues and alkaline forms have stronger RFO-hydrolysing activity than acid forms. By inducible gene silencing of three alkaline forms of α-Gals, stachyose was highly accumulated in RNAi-CsAGA2 plants, while raffinose and stachyose were highly accumulated in RNAi-CsAGA1 plants. The content of sucrose, glucose and fructose was decreased in both RNAi-CsAGA1 and RNAi-CsAGA2 plants after ß-estradiol treatment. In addition, the fresh- and dry-weight of fruits were significantly decreased in RNAi-CsAGA1 and RNAi-CsAGA2 plants. In cucurbitaceous plants, the non-sweet motif within the promoter of ClAGA2 is widely distributed in the promoter of its homologous genes. Taken together, we found RFOs hydrolysis occurred in the vascular tissues of fruits. CsAGA1 and CsAGA2 played key but partly distinct roles in the hydrolysis of RFOs.


Assuntos
Cucumis sativus/enzimologia , Frutas/enzimologia , Oligossacarídeos/metabolismo , Rafinose/metabolismo , alfa-Galactosidase/metabolismo , Cucumis sativus/metabolismo , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas , Floema/enzimologia , Floema/metabolismo , Regiões Promotoras Genéticas , Especificidade por Substrato , alfa-Galactosidase/genética
8.
J Agric Food Chem ; 69(44): 13227-13234, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34709809

RESUMO

Succinate dehydrogenase (SDH, EC 1.3.5.1) has proven to be an important fungicidal target, and the inhibition of SDH is useful in the treatment of plant pathogens. The discovery of a novel active SDH inhibitor is of high value. Herein, we disclose the discovery of a potent, highly active inhibitor as a fungicide candidate by using a computational substitution optimization method, a fast drug design method developed in our laboratory. The greenhouse experiments showed that compound 17c exhibited high protective activity against south corn rust, soybean rust (SBR), and rice sheath blight at a very low dosage of 0.781 mg/L. Moreover, the field trials indicated that compound 17c is comparable to and even better than commercial fungicides against SBR and cucumber powdery mildew at 50 mg/L concentration. Most surprisingly, compound 17c resulted to be strictly better in curative activity than the commercial fungicide benzovindiflupyr. The computation results indicated that 17c could form another hydrogen bond with C_S42 and then lead to strong van der Waals and electronic interactions with SDH. Our results suggested that 17c is a potential fungicide candidate for SDH.


Assuntos
Basidiomycota , Cucumis sativus , Fungicidas Industriais , Basidiomycota/metabolismo , Cucumis sativus/metabolismo , Desenho de Fármacos , Fungicidas Industriais/farmacologia , Doenças das Plantas , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo
9.
Ecotoxicol Environ Saf ; 227: 112879, 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34649142

RESUMO

Cinnamic acid (CA), one of the main autotoxins secreted by cucumber roots during continuous cropping, inhibits plant growth and reduces yield. Silicon (Si) is an environmentally friendly element that alleviates abiotic stresses in plants, but the mechanism underlying its resistance to autotoxicity remain unclear. Here, we used 0.8 mmol L-1 CA to study the effects of Si application on the growth, chlorophyll fluorescence, and ascorbate-glutathione (AsA-GSH) cycle of cucumber seedlings under CA inducing conditions. Our results indicated that CA significantly induced photoinhibition and overaccumulation of reactive oxygen species (ROS), thereby inhibiting cucumber growth. Treatment with 1.0 mmol L-1 Si improved plant height, stem diameter and biomass accumulation, and protected the photosynthetic electron transport function of photosystem II in the presence of CA. Similarly, Si application maintained the ROS status by increasing ascorbate (AsA) and glutathione (GSH) production, as well as the ratios of AsA/DHA and GSH/GSSG in both leaves and roots during CA stress. In addition, Si application in CA-treated seedlings enhanced the activity of key enzymes such as ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione S-transferase (GST), and the transcription of several enzyme genes (CsAPX, CsMDHAR and CsGR) from the AsA-GSH cycle. These results suggest that exogenous Si enhances CA tolerance in cucumber seedlings by protecting photosystem II activity, upregulating AsA-GSH pathway, and reducing ROS levels.


Assuntos
Cucumis sativus , Silício , Cinamatos , Glutationa , Complexo de Proteína do Fotossistema II , Folhas de Planta
10.
BMC Plant Biol ; 21(1): 454, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34615487

RESUMO

BACKGROUND: Photosynthesis in the green leafless blade tissues or organs of plants has been studied in some plants, but the photosynthetic characteristics of stems and petioles are poorly understood. Cucurbitaceous plants are climbing plants that have substantial stem and petiole biomass. Understanding the photosynthetic contribution of cucumber stems and petioles to their growth and the underlying molecular mechanisms are important for the regulating of growth in cucumber production. RESULTS: In this study, the photosynthetic capacity of cucumber stems and petioles were determined by 14CO2 uptake. The total carbon fixed by the stems and petioles was approximately 4% of that fixed by one leaf blade in the cucumber seedling stage, while the proportion of the carbon accumulated in the stems and petioles that redistributed to sink organs (roots and shoot apexes) obviously increased under leafless conditions. The photosynthetic properties of cucumber stems and petioles were studied using a combination of electron microscopy and isotope tracers to compare these properties of stems and petioles with those of leaf blade using two genotypes of cucumber (dark green and light green). Compared with those of the leaf blades, the chlorophyll contents of the cucumber stems and petioles were lower, and the stems and petioles had lower chloroplast numbers and lower stoma numbers but higher thylakoid grana lamella numbers and larger stoma sizes. The Chl a/b ratios were also decreased in the petioles and stems compared with those in the leaf blades. The total photosynthetic rates of the stems and petioles were equivalent to 6 ~ 8% of that of one leaf blade, but the respiration rates were similar in all the three organs, with an almost net 0 photosynthetic rate in the stems and petioles. Transcriptome analysis showed that compared with the leaf blades, the stems and petioles has significantly different gene expression levels in photosynthesis, porphyrin and chlorophyll metabolism; photosynthetic antenna proteins; and carbon fixation. PEPC enzyme activities were higher in the stems and petioles than in the leaf blades, suggesting that the photosynthetic and respiratory mechanisms in stems and petioles are different from those in leaf blade, and these results are consistent with the gene expression data. CONCLUSIONS: In this study, we confirmed the photosynthetic contribution to the growth of cucumber stems and petioles, and showed their similar photosynthetic patterns in the terms of anatomy, molecular biology and physiology, which were different from those of cucumber leaf blades.


Assuntos
Cucumis sativus/crescimento & desenvolvimento , Cucumis sativus/genética , Fotossíntese/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/genética , Produtos Agrícolas/genética , Produtos Agrícolas/crescimento & desenvolvimento , Cucumis sativus/metabolismo , Variação Genética , Genótipo
11.
Ying Yong Sheng Tai Xue Bao ; 32(9): 3240-3248, 2021 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-34658210

RESUMO

We explored the effects of addition of sorghum stubble rhizosphere soil on the growth of continuous cropping cucumber and rhizosphere microbial community in a pot experiment. The diffe-rences in soil bacterial and fungal community composition were analyzed with fluorescence quantitative PCR and high-throughput sequencing technology. There were four treatments: CK (no fertilization), T1(fertilizer only), T2(optimized fertilization), and T3(optimized fertilization + rhizosphere soil of sorghum stubble). The results showed that compared with other treatments, T3 promoted the growth and development of cucumber, and increased the abundance of 16S rRNA and ITS rRNA genes in soil. Compared with the T1 treatment, T2 and T3 significantly increased the richness and diversity of bacterial communities. There was no significant difference in fungal community richness and diversity among different treatments. Adding rhizosphere soil of sorghum stubble changed the composition of bacterial and fungal communities at both phylum and genus levels. For bacteria, it increased the abundances of Acidobacteria and Bacteroides, but decreased that of Proteobacteria, Firmicutes, Nitrospira and Bacillus. For fungi, it increased the abundance of Basidiomycota, Trichoderma and Pseudurotium, but decreased that of Fusarium and Metarhizium. Results of redundancy analysis showed that soil nitrate and organic matter were the key factors affecting the difference of bacterial and fungal community composition, respectively. In conclusion, addition of sorghum stubble rhizosphere soil improved the total abundance of soil microorganisms and bacterial diversity for continuous cropping cucumber. It increased the abundance of beneficial bacteria Trichoderma, reduced that of pathogenic Fusarium, and maintained the survival rate of cucumber, thus provided a feasible solution for alleviating the barriers for the continuous cropping of cucumber.


Assuntos
Cucumis sativus , Sorghum , RNA Ribossômico 16S , Rizosfera , Solo , Microbiologia do Solo
12.
Molecules ; 26(19)2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34641340

RESUMO

Salt concentrations in brine and temperature are the major environmental factors that affect activity of microorganisms and, thus may affect formation of biogenic amines (BAs) during the fermentation process. A model system to ferment cucumbers with low salt (0.5%, 1.5% or 5.0% NaCl) at two temperatures (11 or 23 °C) was used to study the ability of indigenous microbiota to produce biogenic amines and metabolize amino acid precursors. Colony counts for presumptive Enterococcus and Enterobacteriaceae increased by 4 and up to 2 log of CFU∙mL-1, respectively, and remained viable for more than 10 days. 16S rRNA sequencing showed that Lactobacillus and Enterobacter were dominant in fermented cucumbers with 0.5% and 1.5% salt concentrations after storage. The initial content of BAs in raw material of 25.44 ± 4.03 mg∙kg-1 fluctuated throughout experiment, but after 6 months there were no significant differences between tested variants. The most abundant BA was putrescine, that reached a maximum concentration of 158.02 ± 25.11 mg∙kg-1. The Biogenic Amines Index (BAI) calculated for all samples was significantly below that needed to induce undesirable effects upon consumption. The highest value was calculated for the 23 °C/5.0% NaCl brine variant after 192 h of fermentation (223.93 ± 54.40). Results presented in this work indicate that possibilities to control spontaneous fermentation by changing salt concentration and temperature to inhibit the formation of BAs are very limited.


Assuntos
Aminoácidos/análise , Bactérias/classificação , Aminas Biogênicas/análise , Cucumis sativus/microbiologia , Metabolômica/métodos , Sais/química , Bactérias/genética , Bactérias/isolamento & purificação , Cucumis sativus/química , DNA Ribossômico/genética , Fermentação , Microbiologia de Alimentos , Conservação de Alimentos , Concentração de Íons de Hidrogênio , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Cloreto de Sódio/química , Temperatura
13.
Int J Mol Sci ; 22(17)2021 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-34502273

RESUMO

Cucumber (Cucumis sativus L.), an important vegetable plant species, is susceptible to low temperature stress especially during the seedling stage. Vacuolar invertase (VI) plays important roles in plant responses to abiotic stress. However, the molecular and biochemical mechanisms of VI function in cucumber, have not yet been completely understood and VI responses to low temperature stress and it functions in cold tolerance in cucumber seedlings are also in need of exploration. The present study found that hexose accumulation in the roots of cucumber seedlings under low temperature stress is closely related to the observed enhancement of invertase activity. Our genome-wide search for the vacuolar invertase (VI) genes in cucumber identified the candidate VI-encoding gene CsVI1. Expression profiling of CsVI1 showed that it was mainly expressed in the young roots of cucumber seedlings. In addition, transcriptional analysis indicated that CsVI1 expression could respond to low temperature stress. Recombinant CsVI1 proteins purified from Pichia pastoris and Nicotiana benthamiana leaves could hydrolyze sucrose into hexoses. Further, overexpression of CsVI1 in cucumber plants could increase their hexose contents and improve their low temperature tolerance. Lastly, a putative cucumber invertase inhibitor was found could form a complex with CsVI1. In summary, these results confirmed that CsVI1 functions as an acid invertase involved in hexose accumulation and responds to low temperature stress in cucumber seedlings.


Assuntos
Cucumis sativus/fisiologia , Hexoses/metabolismo , Proteínas de Plantas/metabolismo , beta-Frutofuranosidase/metabolismo , Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Genoma de Planta , Filogenia , Proteínas de Plantas/genética , Raízes de Plantas/fisiologia , Saccharomycetales/genética , Plântula/fisiologia , Estresse Fisiológico , Sacarose/metabolismo , Vacúolos/metabolismo , beta-Frutofuranosidase/genética
14.
Physiol Plant ; 173(3): 750-761, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34510478

RESUMO

During recent years, we have advanced our understanding of plant molecular responses to ultraviolet radiation (UV, 280-400 nm); however, how plants respond to UV radiation under different spectral light qualities is poorly understood. In this study, cucumber plants (Cucumis sativus "Lausanna RZ F1") were grown under monochromatic blue, green, red, and broadband white light in combination with UV radiation. The effects of light quality and UV radiation on acclimatory responses were assessed by measuring transcript accumulation of ELONGATED HYPOCOTYL 5 (HY5), CHALCONE SYNTHASE 2 (CHS2), and LIGHT HARVESTING COMPLEX II (LHCII), and the accumulation of flavonoids and hydroxycinnamic acids in the leaves. The growth light backgrounds differentially regulated gene expression and metabolite accumulation. While HY5 and CHS2 transcripts were induced by blue and white light, LHCII was induced by white and red light. Furthermore, UV radiation antagonized the effects of blue, red, green, and white light on transcript accumulation in a gene-dependent manner. Plants grown under blue light with supplementary UV radiation increased phenylalanine, flavonol disaccharide I and caffeic acid contents compared to those exposed only to blue light. UV radiation also induced the accumulation of flavonol disaccharide I and II, ferulic acid hexose and coumaric acid hexose in plants grown under green light. Our findings provide a further understanding of plant responses to UV radiation in combination with different light spectra and contribute to the design of light recipes for horticultural practices that aim to modify plant metabolism and ultimately improve crop quality.


Assuntos
Cucumis sativus , Cucumis sativus/genética , Flavonoides , Hipocótilo , Folhas de Planta , Raios Ultravioleta
15.
J Agric Food Chem ; 69(39): 11720-11732, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34550679

RESUMO

Hydrophobic surfaces modified by pathogens in agricultural production are one of the main reasons to reduce the utilization of pesticides. Adding surfactants to pesticide solutions is a common method to improve their wetting and spreading properties. In this work, the interaction mechanism between pathogen-modified hydrophobic surfaces and mixtures of surfactants and a pesticide was studied in detail. The interaction mechanism was determined by characterizing the wetting and spreading behaviors of droplets on cucumber powdery mildew leaves at different growth stages. When surfactants were added, droplets on cucumber powdery mildew leaves were in the Wenzel wetting state, the pinning force weakened, the contact line speed accelerated, and the adhesion force increased. We explained the micellar state and aggregation behavior of surfactant molecules in a pesticide solution that was applied to the surface of cucumber powdery mildew leaves. Droplets of solutions containing nonionic surfactants easily formed semibald micelles, binding to the pathogen of powdery mildew, whereas droplets containing cationic surfactants did not do so. Because of the electrostatic interaction between cationic surfactant molecules and powdery mildew pathogens, cationic surfactant molecules did not wet the pathogens very well, so we suggest adding nonionic surfactants rather than cationic surfactants to improve the wetting and spreading of pesticide solutions on cucumber powdery mildew leaves. This study provides new insights into enhancing the wetting and deposition of droplets on pathogen-modified hydrophobic surfaces.


Assuntos
Cucumis sativus , Praguicidas , Folhas de Planta , Tensoativos , Molhabilidade
16.
Braz J Biol ; 83: e245865, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495149

RESUMO

Cucumber mosaic virus (CMV) is a tremendous threat to vegetables across the globe, including in Pakistan. The present work was conducted to investigate the genetic variability of CMV isolates infecting pea and spinach vegetables in the Pothwar region of Pakistan. Serological-based surveys during 2016-2017 revealed 31.70% overall CMV disease incidence from pea and spinach crops. Triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) revealed that all the positive isolates belong to CMV subgroup II. Two selected cDNA from ELISA-positive samples representing each pea and spinach crops were PCR-amplified (ca.1100 bp) and sequenced corresponding to the CMV CP gene which shared 93.7% nucleotide identity with each other. Both the sequences of CMV pea (AAHAP) and spinach (AARS) isolates from Pakistan were submitted to GenBank as accession nos. MH119071 and MH119073, respectively. BLAST analysis revealed 93.4% sequence identity of AAHAP isolate with SpK (KC763473) from Iran while AARS isolate shared maximum identity (94.5%) with the strain 241 (AJ585519) from Australia and clustered with some reference isolates of CMV subgroup II from UK (Z12818) and USA (AF127976) in a Neighbour-joining phylogenetic reconstruction. A total of 59 polymorphic (segregating) sites (S) with nucleotide diversity (π) of 0.06218 was evident while no INDEL event was observed in Pakistani isolates. The evolutionary distance of Pakistani CMV isolates was recorded as 0.0657 with each other and 0.0574-0.2964 with other CMV isolates reported elsewhere in the world. A frequent gene flow (Fst = 0.30478 <0.33) was observed between Pakistani and earlier reported CMV isolates. In genetic differentiation analysis, the value of three permutation-based statistical tests viz; Z (84.3011), Snn (0.82456), and Ks* (4.04042) were non-significant. The statistical analysis revealed the values 2.02535, 0.01468, and 0.71862 of Tajima's D, Fu, & Li's F* and D* respectively, demonstrating that the CMV population is under balancing selection.


Assuntos
Cucumis sativus , Cucumovirus , Cucumovirus/genética , Variação Genética , Paquistão , Ervilhas , Filogenia , Doenças das Plantas , Spinacia oleracea
17.
Plant Physiol Biochem ; 167: 132-139, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34352516

RESUMO

Imidazolium-based ionic liquids (ILs) have unique and tunable features with high potential in industrial use. However, the utilization of the ILs in industrial processes has recently arisen the question of their disposal and the effect on the environment. Therefore, in the present study, we investigated the effect of two commercial imidazolium-based ILs, 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) and 1-decyl-3-methylimidazolium chloride ([Dmim][Cl]) on the growth and chemical composition of widely grown vegetables - tomato and cucumber. Different concentrations (10, 100 or 1000 mg L-1) of [Bmim][Cl] and [Dmim][Cl] were applied to the soil on which tomato was cultivated. After the harvest of tomato fruits, the same soil was used to grow and analyze the growth and chemical composition of cucumber. ILs significantly reduced shoot biomass and yield of tomato and significantly changed concentrations of N, K, Ca, Fe and Mn in the leaves, whereas concentrations of P, Cu and Zn were at the level of respected controls. The number of fruits of cucumber, grown on the soil previously treated with ILs, was significantly reduced along with yield, and mineral composition of leaves was significantly altered, with the exception to Cu. [Dmim][Cl] in general affected both tomato and cucumber more than [Bmim][Cl]. The application of IL with a longer alkyl substituent ([Dmim][Cl]) increased the temperature inside the tomato canopy and accelerated the senescence of plants.


Assuntos
Cucumis sativus , Líquidos Iônicos , Lycopersicon esculentum , Minerais , Folhas de Planta
18.
Environ Pollut ; 289: 117854, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34333267

RESUMO

Expanding applications of metal-oxide nanoparticles (NPs) and increased environmental deposition of NPs followed by their interactions with edible crops threaten yields. This study demonstrates the effects of aging (45 days in soil) of four NPs (ZnO, CuO, Al2O3, TiO2; 3.9-34 nm) and their corresponding metal oxide bulk particles (BPs; 144-586 nm) on cucumbers (Cucumis sativus L.) cultivated in sandy-clay-loam field soil and compares these with the phytotoxic effects of readily soluble metal salts (Zn2+, Cu2+, and Al3+). Data revealed the cell-to-cell translocations of NPs, their attachments to outer and inner cell surfaces, nuclear membranes, and vacuoles, and their upward movements to aerial parts. Metal bioaccumulations in cucumbers were found in the order: (i) ZnO-NPs > ZnO-BPs > Zn2+, (ii) CuO-NPs > CuO-BPs > Cu2+, (iii) Al3+> Al2O3-NPs > Al2O3-BPs and (iv) TiO2-NPs > TiO2-BPs. Aging of NPs in soil for 45 days significantly enhanced metal uptake (P ≤ 0.05), for instance aged ZnO-NPs at 1 g kg-1 increased the uptake by 20.7 % over non-aged ZnO-NPs. Metal uptakes inhibited root (RDW) and shoot (SDW) dry weight accumulations. For Cu species, maximum negative impact (%) was exhibited by Cu2+ (RDW:SDW = 94:65) followed by CuO-NPs (RDW:SDW = 78:34) and CuO-BPs (RDW:SDW = 27:22). Aging of NPs/BPs at 1-4 g kg-1 further enhanced the toxic impact of tested materials on biomass accumulations and chlorophyll formation. NPs also induced membrane damage of root tissues and enhanced levels of antioxidant enzymes. The results of this study suggest that care is required when aged metal-oxide NPs of both essential (Zn and Cu) and non-essential (Al and Ti) metals interact with cucumber plants, especially, when they are used for agricultural purposes.


Assuntos
Cucumis sativus , Nanopartículas Metálicas , Nanopartículas , Óxido de Zinco , Bioacumulação , Argila , Cobre/análise , Cobre/toxicidade , Íons , Nanopartículas Metálicas/toxicidade , Óxidos , Areia , Solo , Óxido de Zinco/toxicidade
19.
Plant Physiol Biochem ; 167: 101-112, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34340024

RESUMO

Hydrogen sulfide (H2S) is a novel gaseous signaling molecule in response to adversity stress. Melatonin (MT) is a multifunctional molecule that plays an important role in regulating plant stress resistance. However, the interactions between H2S and MT are still unknown. Therefore, the role of H2S in MT-induced salt tolerance was elucidated in this study by measuring the antioxidant defense system and photosynthetic characteristics of cucumber. In addition, the crosstalk among H2S, NO, and mitogen-activated protein kinase (MAPK) was investigated. Results showed that MT induced the production of H2S by significantly increasing the activity of L-/D-cysteine desulfhydrase, thereby regulating photosynthetic efficiency, antioxidant enzyme activity, and antioxidant enzyme gene expression in cucumber, thus alleviating reactive oxygen species burst by salt stress. In this process, the H2S and NO induced by MT were inhibited by NO scavenger (cPTIO) and H2S scavenger (HT) but not affected by MAPK inhibitor (U0126). Intriguingly, the expression of MAPK3/4/6/9 was inhibited by HT and cPTIO. These results suggested that H2S may act as downstream of MT, interact with NO and MAPK cascades, and jointly participate in the process of MT mitigating salt stress in cucumber. In addition, H2S and NO are upstream signaling molecules of the MAPK cascades.


Assuntos
Cucumis sativus , Sulfeto de Hidrogênio , Melatonina , Melatonina/farmacologia , Óxido Nítrico , Tolerância ao Sal
20.
Anal Chem ; 93(34): 11660-11668, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34403244

RESUMO

An optimized micro-X-ray fluorescence confocal imaging (µXRF-CI) analytical method has been developed to determine the 2D distribution of elemental composition in small (1-3 mm) biological objects at a 10-20 µm spatial resolution. Plants take up chemical elements from soil, and the vascular system transports them toward shoots. In order to obtain biochemical information related to this biological process, 2D distributions of chemical elements in roots and in hypocotyls of cucumber plants were analyzed by synchrotron radiation based on micro-X-ray fluorescence computer tomography and µXRF-CI techniques. The experiments were carried out at HASYLAB Beamline L of the DORIS-III storage ring in Hamburg, a facility that provided optimal physical conditions for developing and performing these unique analyses: high flux monochromatic synchrotron beam, X-ray optical elements, precision moving stages, and silicon drift detectors. New methodological improvements and experimental studies were carried out for applicability of lyophilized samples and cryo-cooling. Experimental parameters were optimized to maximize the excitation yield of arsenic Kα radiation and improvement of the spatial resolution of the µXRF-CI analytical method.


Assuntos
Arsênio , Cucumis sativus , Hipocótilo , Espectrometria por Raios X , Síncrotrons , Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...