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Agronomy
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Functional Metabolism in Crops/Agronomy
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Functional Metabolism in Crops/Agronomy

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Crop Breeding and Genetics".

Deadline for manuscript submissions: closed (1 May 2019) | Viewed by 54778

Special Issue Editor

Prof. Dr. José M. Palma

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Guest Editor
Department of Stress, Development and Signaling in Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
Interests: fruit and vegetable antioxidants; reactive oxygen and nitrogen species; fruit ripening; transcriptomics; proteomics; metabolomics
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Since the initial years of Agriculture in the Neolithic, man has been always aware of the crop benefits for health. Thus, the search for new and more nutritive agro produce has been the target for human communities and, accordingly, breeding strategies have been developed in search of novel species and varieties destined to human consume. From the early contributions in Old Persian, Egyptian and Greek cultures till the present days, the agricultural science has evolved enormously. From the simple description of natural compounds contained in our crops, as it has been made till recent years, research nowadays seeks for thus far unreported functional molecules which contribute to maintaining and improving our health status, but also to understand how plants cope against unfavorable conditions promoted by different agents such as salinity, drought, flooding, cold, heavy metals, pathogens, and others.

The development of cutting edge throughput and fine technologies are greatly helping the objectives of the current agricultural science. Approaches such as genomics, proteomics, metabolomics, ionomics, and others initiatives which combine the accurate individualization of molecules (genes, proteins, metabolites) with their identification and quantification are providing a bulk of data with agricultural, industrial and commercial potentialities.

This Special Issue will be focused on Functional Metabolism in Crops/Agronomy and it is expected to be an Agora where plant biologists with expertise in the response of agricultural species to biotic and abiotic stresses, the new growing strategies to increase the nutritional value of plant products, the ripening and post-harvest of fruits, the antioxidative and functional compounds present in crops, and the new technologies applied to the improvement of agriculture, will bring their knowledge to be shared with the scientific community, farmers and companies.

Prof. José Palma
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Agronomy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Crop culture
  • Fruit metabolism
  • Fruit genomics
  • Fruit proteomics
  • Fruit metabolomics
  • Functional crops
  • Plant
  • Stress

Published Papers (11 papers)

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Research

13 pages, 1451 KiB  
Article
Metabolomics Analysis Reveals the Mechanism of Hydrogen Cyanamide in Promoting Flower Bud Break in Blueberry
by Hao Wang, Xiuying Xia and Lijia An
Agronomy 2021, 11(1), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11010102 - 07 Jan 2021
Cited by 8 | Viewed by 2922
Abstract
Bud dormancy of deciduous fruit trees is a complex process that allows trees to survive long periods in adverse conditions during winter. Dormancy is a major obstacle for both fruit production in mild winter areas and off-season culture of fruit trees in protection [...] Read more.
Bud dormancy of deciduous fruit trees is a complex process that allows trees to survive long periods in adverse conditions during winter. Dormancy is a major obstacle for both fruit production in mild winter areas and off-season culture of fruit trees in protection facilities. It is very economically advantageous to be able to control the time point of bud break and consequently harvest in crops with high returns and short harvest seasons like blueberry (Vaccinium spp.). Hydrogen cyanamide (H2CN2 (HC)) treatment is an effective method to promote dormancy release and synchronize bud break in perennial deciduous fruit trees, including blueberry. However, there are few systematic studies of the metabolic changes that occur during HC-induced bud breaking. In this study, the metabolome of blueberry buds under forced conditions following HC and water treatment (control) was analyzed using gas chromatography paired with time-of-flight mass spectrometry (GC–TOFMS) technology. A total of 252 metabolites were identified and 16 differential metabolites (VIP > 1, p < 0.05) were detected. The levels of several soluble sugars (fructose, glucose, maltose), organic acids (citric acid, alpha-ketoglutaric, succinic acid), and amino acids (aspartic acid, glutamic acid, phenylalanine) were upregulated, while tyrosine, tryptophan, and asparagine were significantly downregulated in HC-treated buds when compared with control buds. The synthesis and accumulation of phenylpropanoids (salicin, 4-vinylphenol, neohesperidin) were also promoted by HC. These results suggest that alteration of carbohydrate and amino acid metabolism, tricarboxylic acid (TCA) cycle increase, and phenylpropanoid accumulation were crucial in HC-promoted bud breaking in blueberry. This research extends our understanding of the mechanisms involved in dormancy release induced by HC and provides a theoretical basis for applying HC to accelerate bud break. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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21 pages, 2630 KiB  
Article
Effect of Drought Stress at Reproductive Stages on Growth and Nitrogen Metabolism in Soybean
by Yanli Du, Qiang Zhao, Liru Chen, Xingdong Yao and Futi Xie
Agronomy 2020, 10(2), 302; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy10020302 - 20 Feb 2020
Cited by 58 | Viewed by 7207
Abstract
This study aims to determine variability among soybean (Glycine max (L.) Merr.) cultivars under drought conditions and how nitrogen metabolites, metabolism-related enzymes, and gene expression vary during soybean growth. Three soybean cultivars, Shennong17 (CV.SN17), Shennong8 (CV.SN8), and Shennong12 (CV.SN12), were grown in [...] Read more.
This study aims to determine variability among soybean (Glycine max (L.) Merr.) cultivars under drought conditions and how nitrogen metabolites, metabolism-related enzymes, and gene expression vary during soybean growth. Three soybean cultivars, Shennong17 (CV.SN17), Shennong8 (CV.SN8), and Shennong12 (CV.SN12), were grown in pot culture and subjected to drought stress at reproductive stages for 45 days. The results showed that long-term drought stress decreased biomass allocation to reproductive organs, weakened antioxidant capacity, and reduced seed weight, effects that were less pronounced in CV.SN12 compared with those in CV.SN8 and CV.SN17. Drought stress decreased the concentrations of nitrogen and soluble protein but increased nitrate concentration in leaves. This was related to the significantly reduction of nitrogen metabolism efficiency, including decreased activities of nitrogen metabolism enzymes, and downregulated expression of GmNR, GmNiR, GmGS, and GmGOGAT. Drought stress increased the concentrations of free amino acid, proline, and soluble sugar in leaves to enhance the osmotic adjustment ability. Furthermore, soybean seed weight showed significantly correlation (p < 0.05) with nitrogen-metabolism-related parameters. Based on the performance of growth, nitrogen metabolism, and yield attributes, CV.SN12 showed the highest tolerance to drought, followed by CV.SN8 and CV.SN17. In addition, these nitrogen-metabolism-related parameters could be used in soybeans to select for drought tolerance. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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18 pages, 21627 KiB  
Article
Comparative Transcriptome Analysis Identified Differentially Expressed Genes between Male and Female Flowers of Zanthoxylum armatum var. novemfolius
by Xian Zhang, Ning Tang, Xiaomeng Liu, Jiabao Ye, Jingyi Zhang, Zexiong Chen, Feng Xu, Weiwei Zhang and Yongling Liao
Agronomy 2020, 10(2), 283; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy10020283 - 16 Feb 2020
Cited by 10 | Viewed by 3790
Abstract
As a traditional spicy condiment, Zanthoxylum armatum var. novemfolius is of high economical and medicinal value. Despite the long history of human cultivation, the molecular mechanisms underlying flower development are still poorly understood in Z. armatum. In this study, we performed de [...] Read more.
As a traditional spicy condiment, Zanthoxylum armatum var. novemfolius is of high economical and medicinal value. Despite the long history of human cultivation, the molecular mechanisms underlying flower development are still poorly understood in Z. armatum. In this study, we performed de novo transcriptome assembly and comparative analysis of female and male flowers in Z. armatum. A total of 94,771 unigenes were obtained, and 50,605 unigenes were successfully annotated against the public database. Transcriptome data showed that 20,431 annotated unigenes were differentially expressed genes. KEGG enrichment analysis revealed that the most representative pathway was plant hormone signal transduction. Among them, 41, 16, 41, 27, 95, and 40 unigenes were involved in the biosynthesis and signaling of abscisic acid, ethylene, cytokinin, gibberellin, auxin, and jasmonic acid, respectively. Transcription factors also played crucial roles in flower development, such as AGL11, PMADS2, and NAC. These results provided an important basis for characterizing the potential mechanism of flower development and enriching the knowledge of reproduction genetics in Z. armatum. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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14 pages, 2049 KiB  
Article
Metabolic Changes and Increased Levels of Bioactive Compounds in White Radish (Raphanus sativus L. cv. 01) Sprouts Elicited by Oligochitosan
by Apidet Rakpenthai, Gholamreza Khaksar, Meike Burow, Carl Erik Olsen and Supaart Sirikantaramas
Agronomy 2019, 9(8), 467; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9080467 - 19 Aug 2019
Cited by 12 | Viewed by 4035
Abstract
The effect of oligochitosan O-80 treatment on metabolic changes in white radish (Raphanus sativus L.) sprouts (WRS) was investigated for its potential to enhance bioactive compounds accumulation. The seeds were germinated in deionized water containing different concentrations of oligochitosan O-80 (0 (control), [...] Read more.
The effect of oligochitosan O-80 treatment on metabolic changes in white radish (Raphanus sativus L.) sprouts (WRS) was investigated for its potential to enhance bioactive compounds accumulation. The seeds were germinated in deionized water containing different concentrations of oligochitosan O-80 (0 (control), 5, 10, 20 and 40 ppm). Seven-day old sprouts were harvested for metabolome analysis using liquid chromatography-mass spectrometry (LC-MS) and high-performance liquid chromatography (HPLC) for phenolic compounds and glucosinolate analysis, respectively, and spectrophotometric assays to determine the total phenolic content and antioxidant capacity. Partial least squares discriminant analysis was adopted to model the data from the LC-MS and revealed that O-80 at all tested concentrations affected the metabolite profiles of the treated WRS samples. The UV chromatogram at 320 nm showed increased levels of most sinapoyl derivatives, consistent with the increased total phenolic contents. Interestingly, glucoraphasatin (4-methylthio-3-butenyl glucosinolate), a major glucosinolate detected by HPLC, was increased by 40% in the sprouts treated with 10 ppm O-80. Our results provide compelling evidence regarding the exogenous application of oligochitosan O-80 as an elicitor of bioactive metabolites in WRS. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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14 pages, 9309 KiB  
Article
Pomegranate (Punica granatum L.) Fruits: Characterization of the Main Enzymatic Antioxidants (Peroxisomal Catalase and SOD Isozymes) and the NADPH-Regenerating System
by Melisa Pinilla, Jessica Iglesias-Moya, María Jesús Campos, Francisco J. Corpas and José M. Palma
Agronomy 2019, 9(6), 338; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9060338 - 25 Jun 2019
Cited by 7 | Viewed by 5521
Abstract
Pomegranate (Punica granatum L.) is a common edible fruit. Its juice can be used as a source of antioxidative compounds, primarily polyphenols and vitamin C, in addition to other vitamins and minerals. Nevertheless, little is still known about how the enzymatic machinery, [...] Read more.
Pomegranate (Punica granatum L.) is a common edible fruit. Its juice can be used as a source of antioxidative compounds, primarily polyphenols and vitamin C, in addition to other vitamins and minerals. Nevertheless, little is still known about how the enzymatic machinery, mainly that related to oxidative metabolism, is influenced by the genotype and the environmental and climate conditions where pomegranate plants grow. In this work, seeds and juices from two pomegranate varieties (Valenciana and Mollar) grown in two different Spanish locations were assayed. Both varieties showed clear differences in their respective polypeptide profiles. The analysis of the isoenzymatic superoxide dismutase (SOD) activity pattern displayed one Mn-SOD and five CuZn-SODs (I–V) whose abundances depended on the variety. Furthermore, by immunoblot assays, at least one additional Fe-SOD with a subunit size of about 23 kDa was also detected in both varieties. Besides this, the presence of the H2O2-scavenging peroxisomal catalase in seeds and juice indicates that an active metabolism of reactive oxygen species (ROS) takes place in this fruit, but the two pomegranate varieties showed opposite activity profiles. The activities of the main NADPH-regenerating enzymes, including glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphlogluconate dehydrogenase (6PGDH), NADP-dependent isocitrate dehydrogenase (NADP-ICDH), and NADP-dependent malic enzyme (NADP-ME), were studied in the same plant materials, and they behaved differently depending on the genotype. Finally, our data demonstrate the presence of two specific enzymes of the peroxisomal glyoxylate cycle, malate synthase (MS) and isocitrate lyase (ICL). These enzymes participate in oilseeds by channeling the lipid catabolism to the carbohydrate synthesis for further use in seed germination and early seedling growth. The results obtained in this work indicate that a similar mechanism to that reported in oilseeds may also operate in pomegranate. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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12 pages, 2052 KiB  
Article
UV-B Exposure of Black Carrot (Daucus carota ssp. sativus var. atrorubens) Plants Promotes Growth, Accumulation of Anthocyanin, and Phenolic Compounds
by Renate Müller, José R. Acosta-Motos, Dominik K. Großkinsky, José A. Hernández, Henrik Lütken and Gregorio Barba-Espin
Agronomy 2019, 9(6), 323; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9060323 - 19 Jun 2019
Cited by 10 | Viewed by 6672
Abstract
Black carrot (Daucus carota L. ssp. sativus var. atroburens) is a root vegetable with anthocyanins as major phenolic compounds. The accumulation of phenolic compounds is a common response to UV-B exposure, acting as protective compounds and as antioxidants. In the present [...] Read more.
Black carrot (Daucus carota L. ssp. sativus var. atroburens) is a root vegetable with anthocyanins as major phenolic compounds. The accumulation of phenolic compounds is a common response to UV-B exposure, acting as protective compounds and as antioxidants. In the present study, black carrot plants grown under a 12-h photoperiod were supplemented with UV-B radiation (21.6 kj m−2 day−1) during the last two weeks of growth. Carrot taproots and tops were harvested separately, and the effect of the UV-B irradiance was evaluated in terms of size (biomass and length), total monomeric anthocyanin content (TMC), total phenolic content (TPC), and phytohormones levels. The results showed that UV-B irradiance promoted plant growth, as shown by the elevated root (30%) and top (24%) biomass, the increased TMC and TPC in the root (over 10%), and the increased TPC of the top (9%). A hormone analysis revealed that, in response to UV-B irradiance, the levels of abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) decreased in tops while the level of the cytokinins cis-zeatin (cZ) and trans-zeatinriboside (tZR) increased in roots, which correlated with an amplified growth and the accumulation of anthocyanins and phenolic compounds. Beyond the practical implications that this work may have, it contributes to the understanding of UV-B responses in black carrot. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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15 pages, 2176 KiB  
Article
Brassinosteroids Regulate Antioxidant System and Protect Chloroplast Ultrastructure of Autotoxicity-Stressed Cucumber (Cucumis sativus L.) Seedlings
by Ping Yang, Muhammad Azher Nawaz, Fuxin Li, Lisha Bai and Jie Li
Agronomy 2019, 9(5), 265; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9050265 - 26 May 2019
Cited by 18 | Viewed by 4440
Abstract
Autotoxicity is a common problem being faced in protected vegetable cultivation system. Phytoremediation of plant autotoxicity is an emerging concept to minimize deterioration of soil environment and reduction of yield and quality of vegetable crops. Brassinosteroids (BRs) have been reported as a potential [...] Read more.
Autotoxicity is a common problem being faced in protected vegetable cultivation system. Phytoremediation of plant autotoxicity is an emerging concept to minimize deterioration of soil environment and reduction of yield and quality of vegetable crops. Brassinosteroids (BRs) have been reported as a potential phytohormone to assist phytoremediation. However, the effects of BRs-induced autotoxicity stress on plant growth, photosynthesis and antioxidant defense system are poorly understood. Hence, we focused on the changes in physiological characteristics and ultrastructure of cucumber leaves in response to the application of 24-epibrassinolide (EBR) under autotoxicity stress conditions. The results showed that leaf area, plant height, fresh weight and dry weight of cucumber were obviously decreased under autotoxicity stress conditions. EBR application obviously improved the phenotypic characteristics of cucumber seedlings. Chlorophyll content, net photosynthetic rate, stomatal conductance and transpiration rate of cucumber leaves were markedly reduced under autotoxicity stress conditions. Application of EBR improved the photosynthetic pigments (chlorophyll a by 15.80%, chlorophyll b by 18.70% and total chlorophyll content by 17.30%), net photosynthetic rate by 36.40% and stomatal opening of leaves under autotoxicity stress conditions. EBR application also maintained the integrity of chloroplast and thylakoid structures under autotoxicity stress conditions. The activity of catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) and antioxidative compounds ascorbate (AsA) and reduced glutathione (GSH) contents were markedly decreased, however, these were obviously increased after EBR application under autotoxicity stress. EBR application also increased the soluble sugar and protein, and proline concentration by 59.70%, 7.22% and 36.58%, respectively in the leaves of cucumber, decreased malondialdehyde by 24.13% and reactive oxygen species contents (H2O2 by 35.17%, O2− by 12.01% and •OH by 16.59%), and reduced the relative permeability of the cell membrane by 14.31%. These findings suggest that EBR application enhanced the photosynthetic capacity of leaves, maintained the integrity of chloroplast and thylakoid structures, and effectively alleviated the damage of membrane caused by lipid peroxidation and root damage under autotoxicity stress conditions. The growth inhibition effect of autotoxicity stress on cucumber was reduced by EBR application. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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12 pages, 1225 KiB  
Article
Variability in Anthocyanins, Phenolic Compounds and Antioxidant Capacity in the Tassels of Collected Waxy Corn Germplasm
by Prakasit Duangpapeng, Kamol Lertrat, Khomsorn Lomthaisong, Marvin Paul Scott and Bhalang Suriharn
Agronomy 2019, 9(3), 158; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9030158 - 25 Mar 2019
Cited by 13 | Viewed by 3934
Abstract
Corn tassel is a valuable co-product and an excellent source of phytochemicals with bioactive properties. The information on the genetic diversity in the tassel properties of waxy corn germplasm is important for creating new varieties that can have the potential for the commercial [...] Read more.
Corn tassel is a valuable co-product and an excellent source of phytochemicals with bioactive properties. The information on the genetic diversity in the tassel properties of waxy corn germplasm is important for creating new varieties that can have the potential for the commercial production of tassels as a co-product. Therefore, the objective of this study was to evaluate the potential of corn tassels in a set of waxy corn germplasm for the extraction of phenolic compounds with an antioxidant activity. The experiment was carried out under field conditions in the rainy season 2017 and the dry season 2017/2018. Fifty waxy corn genotypes were evaluated. Data were collected for the total anthocyanin content (TAC), total phenolic content (TPC) and the antioxidant activity was determined by the 2,2-diphenyl−1-picrylhydrazyl (DPPH) radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) assays. The season (S) had small effect on all of the parameters, accounting for 0.2–8.7% of the total variance. The genotype (G) was the largest variance component in the TAC and DPPH radical scavenging activity, accounting for 83.5–97.5% of the total variance. The G and S × G interaction contributed approximately equally to the total variance in the TPC and TEAC. Based on the TAC, TPC and antioxidant capacity variation, the genotypes were classified into seven groups. The tassels of corn genotypes belonging to three of these clusters (clusters E, F and G) had high levels of phytochemicals along with an antioxidant capacity. A significant correlation coefficient was found between the TAC and DPPH (r = 0.70 **). The TPC showed a moderate relationship with the DPPH and TEAC assays (r = 0.60 ** and 0.76 **, respectively). The information obtained from this study can be used for germplasm management and waxy corn breeding for enhancing levels of bioactive properties in waxy corn tassels. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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17 pages, 1768 KiB  
Article
Growth, Secondary Metabolites and Enzyme Activity Responses of Two Edible Fern Species to Drought Stress and Rehydration in Northeast China
by Yanlin Wang, Shanshan Gao, Xingyuan He, Yan Li, Peiyang Li, Yue Zhang and Wei Chen
Agronomy 2019, 9(3), 137; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy9030137 - 16 Mar 2019
Cited by 24 | Viewed by 3732
Abstract
The drought resistance mechanism of Matteuccia struthiopteris (L.) Todar. and Athyrium multidentatum (Doll.) Ching were measured under natural drought exposure. The results showed that the two edible fern species showed stronger resistance in the early stages of drought, mainly expressed as the decrease [...] Read more.
The drought resistance mechanism of Matteuccia struthiopteris (L.) Todar. and Athyrium multidentatum (Doll.) Ching were measured under natural drought exposure. The results showed that the two edible fern species showed stronger resistance in the early stages of drought, mainly expressed as the decrease of relative leaf water content (RLWC), increase of osmotic substances, secondary metabolites such as flavonoids (FC), total phenols (TPC), proantho cyanidins (PCC) content and enzyme activity (superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX)). The higher RLWC, FC, TPC, PCC and abscisic acid (ABA) content and lower H2O2 content indicates the stronger non-enzymatic antioxidant system and drought resistance of A. multidentatum. However, the proline (Pro) content changed slowly, and the synthesis of soluble protein (SP), total phenols, proantho cyanidins and ABA, SOD activity of two fern species were inhibited in the late stages of drought stress. This study can provide a scientific basis for the cultivation and utilization of edible fern species under forest in Northeast China. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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13 pages, 2637 KiB  
Article
Antioxidant Capacity and UPLC-PDA ESI-MS Phenolic Profile of Stevia rebaudiana Dry Powder Extracts Obtained by Ultrasound Assisted Extraction
by Ana G. Covarrubias-Cárdenas, José Isabel Martínez-Castillo, Nelly Medina-Torres, Teresa Ayora-Talavera, Hugo Espinosa-Andrews, N. Ulises García-Cruz and Neith Pacheco
Agronomy 2018, 8(9), 170; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy8090170 - 31 Aug 2018
Cited by 32 | Viewed by 6065
Abstract
Stevia leaves, which are commonly used as a natural sweetener in food products, have increased in importance for antioxidant delivery due to their high content of phenolic compounds. In this study, the influence of the drying process on stevia leaves, with regards to [...] Read more.
Stevia leaves, which are commonly used as a natural sweetener in food products, have increased in importance for antioxidant delivery due to their high content of phenolic compounds. In this study, the influence of the drying process on stevia leaves, with regards to phenolic content and antioxidant activity during drying kinetics 40 °C for 7 h, was studied. The effect of solvent concentration and extraction time using a 32 factorial design on total phenol content (TPC), and on antioxidant activity of extracts obtained from dried stevia leaves, by ultrasound assisted extraction (UAE) as alternative method was evaluated. Steviol glycosides contents were also evaluated by a conventional and UAE method. Phenols identification, quantification and purification were performed by Ultra Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UPLC-ESI-MS), Ultra Performance Liquid Chromatography-Photodiode Array (UPLC-PDA) and advanced automated flash purification, respectively. Drying time affected the moisture content of stevia leaves. A constant weight was reached after six hours of drying, and higher antioxidant activity was observed, while the highest TPC was obtained after seven hours of drying. The highest TPC (91.57 ± 8.8 mg GAE/g dw) and antioxidant activity (603.24 ± 3.5 μmol TE/g dw) in UAE method was obtained when ethanol 50% at 5 min was used. Steviol glycosides extracted by UAE were recorded with a content of 93.18 ± 1.36 mg/g dw and 98.97 ± 1.75 mg/g dw for stevioside and rebaudioside A respectively. Six phenolic compounds including four phenolic acids and two flavonoids were identified and quantified by UPLC-PDA, and confirmed by ESI-MS reporting its fragmentation pattern. Diosmin and chlorogenic acid were the most abundant compounds with values of 2032.36 μg/mL and 434.95 μg/mL respectively. As a novelty we found that the antioxidant activity evaluated in partially purified fractions suggested that biological activity might be attributed to the synergistic effect of the six phenols present in the stevia leaves extract. In addition to its sweeting properties, stevia leaves constitute a potential source of polyphenolic compounds, with antioxidant activity that could be used as a food additive. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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11 pages, 4547 KiB  
Article
Insights into the Positive Effect of Pyraclostrobin on Sugarcane Productivity
by Amanda Moreira Lopes, Pedro Vitor Schumacher, Aurora Terylene Pérez Martínez, Antônio Paulino da Costa Netto and Antonio Chalfun-Junior
Agronomy 2018, 8(7), 122; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy8070122 - 18 Jul 2018
Cited by 12 | Viewed by 5711
Abstract
Achieving high yields is a challenge for sugarcane producers due to the diverse environmental conditions to which the crop is subjected. In tropical and subtropical regions, where sugarcane is typically cultivated, crop diseases are common. This necessitates the development of disease management techniques. [...] Read more.
Achieving high yields is a challenge for sugarcane producers due to the diverse environmental conditions to which the crop is subjected. In tropical and subtropical regions, where sugarcane is typically cultivated, crop diseases are common. This necessitates the development of disease management techniques. Among these techniques, chemical control is of particular significance due to the development of new antifungal agents, such as pyraclostrobin. For some crops, pyraclostrobin has a positive influence on yield due to its effects on plant physiology. The aim of this study was to evaluate the physiological responses and yield of three sugarcane cultivars treated with the fungicide, pyraclostrobin. The experiment was performed in a randomized block design (RBD) with a split-plot arrangement; the variables analyzed were the application or non-application of fungicide in the plots and, in the subplots, the evaluation times after fungicide application. Both the rate of photosynthesis and the antioxidant enzyme (Superoxide Dismutase, Catalase and Ascorbate Peroxidades) activity increased in plants treated with fungicide in comparison to untreated plants, and in the RB855156 cultivar the stomatal conductance, transpiration, and nocturnal respiratory rate were increased. Furthermore, application of pyraclostrobin increased stalk yield and the green biomass index in the RB855156 and RB86751 sugarcane cultivars. In certain cultivars of sugarcane, application of pyraclostrobin leads to an increased yield. Full article
(This article belongs to the Special Issue Functional Metabolism in Crops/Agronomy)
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