Quality of tomato (Solanum lycopersicum L.) fruits inoculated with Escherichia coli under different storage conditions

The study evaluated the effect of storage temperatures of 7 and 22 °C for 168 h on tomatoes (Charleston cv.) inoculated with 107 CFU mL-1 of the enterotoxigenic Escherichia coli pathogroup (ETEC) strain on color indexes (hue angle, h°, and chroma, C*), firmness, titratable acidity (% citric acid), ascorbic acid, total soluble sugars and reducing sugars (glucose, fructose, and sucrose). ETEC survived with populations of 7 and 9.2 Log CFU g-1 at 7 and 22 °C, respectively until 120 h. Bacterial adherence and colonization under both storage conditions were confirmed by scanning electron microscopy. The index C* and ascorbic acid had higher values at 22 °C, while the parameters h°, firmness, and citric acid had lower values at the same storage temperature. At 7 °C, the concentration of total soluble sugars was affected; glucose and fructose showed lower values (0.054 and 0.057 g 100 g-1, respectively). Finally, the inoculated fruits exhibited significant differences in the parameters of consumer preference of fresh tomatoes such as color, firmness, sugars, and organic acids, which were affected depending on the storage temperature.

Application methods of biostimulants affect the production and postharvest conservation of yellow melon

Worldwide, Brazil holds the fifth position in melon fruits exportation, further expanding its products to provide for the growing demand. This expansion is the result of the development and application of new technologies, including the management of the use of biostimulants. However, for melon crops, the information in the literature on the use of biostimulants remains limited to the effects of different doses on fruit quality at the time of harvest. Therefore, this study aimed to evaluate the influence of different methods of pre-harvest application of two biostimulants on the production and postharvest conservation of fruits of yellow melon cv. Iracema. The treatments consisted of a combination of three factors: two plant biostimulants (Crop Set® and Spray Dunger®), two application methods of the products (fertigation and spraying), and five times of postharvest storage (0, 14, 21, 28 and 35 days). An additional control treatment corresponded to plants without biostimulant application. The fruits were evaluated for production and physicochemical attributes: average mass, yield, flesh firmness, titratable acidity, soluble solids content, SSC/TA ratio, pH, total soluble sugars, and weight loss. Fertigation is the recommended application method of biostimulants for yellow melon due to its effect on the increase of average mass, yield, flesh firmness, soluble solids content, and total soluble sugars of the fruits in relation to the spraying method.

Silicon Mitigates Negative Impacts of Drought and UV-B Radiation in Plants

Due to climate change, plants are being more adversely affected by heatwaves, floods, droughts, and increased temperatures and UV radiation. This review focuses on enhanced UV-B radiation and drought, and mitigation of their adverse effects through silicon addition. Studies on UV-B stress and addition of silicon or silicon nanoparticles have been reported for crop plants including rice, wheat, and soybean. These have shown that addition of silicon to plants under UV-B radiation stress increases the contents of chlorophyll, soluble sugars, anthocyanins, flavonoids, and UV-absorbing and antioxidant compounds. Silicon also affects photosynthesis rate, proline content, metal toxicity, and lipid peroxidation. Drought is a stress factor that affects normal plant growth and development. It has been frequently reported that silicon can reduce stress caused by different abiotic factors, including drought. For example, under drought stress, silicon increases ascorbate peroxidase activity, total soluble sugars content, relative water content, and photosynthetic rate. Silicon also decreases peroxidase, catalase, and superoxide dismutase activities, and malondialdehyde content. The effects of silicon on drought and concurrently UV-B stressed plants has not yet been studied in detail, but initial studies show some stress mitigation by silicon.

Total Soluble Sugar Quantification from Ethanolic Plant Extracts v1

Quantification of total soluble sugars (as glucose) in plant tissue extracts via the sulfuric phenol method adapted for 96 well plates.

Extraction of Non-Structural Carbohydrates (Total Soluble Sugars + Starch) in Plant Tissues v1

Ethanolic extraction of total soluble sugars (liquid fraction) and starch (precipitated fraction) from leaf tissue.

QUALITY OF TABLE CASSAVA ROOTS FERTILIZED WITH PHOSPHORUS1

ABSTRACT The quality parameters of cassava roots vary between cultivars and depend on abiotic factors, such as plant nutrition. However, the magnitude of how these factors interfere is not yet well defined, especially for phosphorus (P), which is a nutrient directly linked to the synthesis of sugars and starches in plants. Thus, the objective of the research was to evaluate the quality of roots of table cassava cultivars fertilized with doses of P in the Brazilian semiarid. The research was carried out at the Rafael Fernandes experimental farm, Mossoró, RN, Brazil, from June 2018 to April 2019. The experimental design used was in randomized blocks, arranged in subdivided plots and with four replications. Doses of P (0, 60, 120, 180 and 240 kg ha-1 of P2O5) were applied in the plots, and in the subplots, the table cassava cultivars (Água Morna, BRS Gema de Ovo, Recife and Venâncio). Firmness, elasticity, titratable acidity, soluble solids, total soluble sugars, starch and cooking were all evaluated. The quality of table cassava roots varied depending on the cultivar and the dose of P. Doses of P between 120 and 240 kg ha-1 of P2O5 increase the starch content and reduce the cooking time of table cassava roots.

Tolerance and Physiological Responses in Two Populations of Harmel Plant to Silver Stress, A Suitable Candidate for Accumulation of Ag

By studying harmel plants in Ag metal-contaminated mineral areas, it was found that harmel plants can accumulate Ag metal, so the present study aimed to investigate the effects of Ag exposure (0, 1, 2.5, 5, 10 mgL− 1 Ag) to harmel seedlings. Two populations (metallicolous and non-metallicolous) were compared about Ag tolerance, Ag accumulation, translocation factor (TF), photosynthetic pigments, antioxidant enzyme activity and, non-enzyme metabolite. At first, harmel plants were studied for their ability to accumulate silver metal in a silver metal-contaminated mineral area. Also, the results of hydroponic culture showed that the increase of Ag concentrations in the nutrient solution reduced root length, shoot length, root dry weight, shoot dry weight, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid and, total soluble sugars in both populations, but the accumulation is more pronounced in metallicolous populations than non-metallicolous. In response to this, the antioxidant activities were increased under Ag exposure, and sharp in the metallicolous population. In conclusion, the above results show that harmel seems a suitable candidate for Ag-accumulation; and these findings support the use of harmel as an acceptable species for cultivation in soils that are contaminated with Ag and strategies to minimize the toxicity of Ag in plants.

Impact of Drought and Flooding on Alkaloid Production in Annona crassiflora Mart

The Brazilian Cerrado is the second largest Brazilian biome. In recent decades, a reduction in rainfall has indicated an extension of the dry season. Among the many native species of the Cerrado of the Annonaceae family and used in folk medicine, Annona crassiflora Mart. has fruits of high nutritional value and its by-products are sources of bioactive compounds, such as alkaloids. The aim of the study was to investigate how water stress impacts the production of alkaloids. The study was carried out in a nursery, and the knowledge was flood, field capacity and drought. Gas exchange, chlorophyll a fluorescence, antioxidant enzymes, total soluble sugars, starch, reducing sugars, sucrose, total alkaloids and liriodenine were analyzed. We observed that plants subjected to drought had an increase in the production of total alkaloids and liriodenine, without a reduction in photosynthetic metabolism. Plants kept under drought and flood conditions dissipated higher peroxidase activity, while catalase was higher in flooded plants. Starch showed the highest concentration in flooding plants without differing from drought plants; the lowest trehalose concentrations were found in both drought and flooding plants. The drought stimulated the synthesis of total alkaloids and liriodenine without reducing the primary metabolism, which suggests adaptation to Cerrado conditions.

Biochemical and Physiological Responses of Thermostable Wheat Genotypes for Agronomic Yield under Heat Stress during Reproductive Stages

Wheat is a globally important crop used as a main staple food in various countries of the world. The current study was conducted with the objective to evaluate the effect of a high temperature (HT) on osmolytes (starch, sucrose, total soluble sugars, total soluble proteins and proline), physiological parameters (Chl-a, Chl-b, photosynthesis rate, transpiration rate and stomatal conductance), antioxidant enzymes (superoxide dismutase, catalase and peroxidase) and agronomic traits (flag leaf area, spike length, and thousand grain weight) during the grain filling and anthesis stages of wheat cultivars (Fakhr-e-Bhakar, Raj-3765, Jimai-22 and Bayraktar-2000) collected from different regions of the world. Separate experiments for both stages were conducted in a glasshouse and treated with two different temperature regimes, i.e., optimum (OT) (24 °C day; 14 °C night) and high temperature (HT) (32 °C day; 22 °C night) in RCBD for two weeks. The data for osmolytes, antioxidant enzymes and physiological contents were collected at days 3, 5, 7, 9 and 13 after the start of plant stress, while the agronomic traits were collected at maturity. The data obtained were subjected to a statistical analysis using the statistix8.1 and R-program. HT stress significantly reduced all the traits except for the membrane damage, transpiration rate, proline and total soluble sugars, whose values increased considerably in the genotype Bayraktar-2000. However, under both regimes of temperature Fakhr-e-Bhakkar showed a high tolerance against HT stress, as revealed by physiological, biochemical and agronomic evaluations. Moreover, correlation, PCA and heat map analyses indicated that all types of traits are significantly interconnected in determining the crop potential to sustain its growth under HT stress.

Screening of Pearl Millet [Pennisetum glaucum [L.] R. Br.] Germplasm Lines against Drought Tolerance Based on Biochemical Traits

Aim: The current investigation was commenced to investigate genetic miscellany among pearl millet genotypes based on diverse biochemical parameters interrelated to drought tolerance. Study Design: In investigation, 96 pearl millet germplasm lines were screened against drought using diverse biochemical traits. Place and Duration of the Study: The present study was conducted at College of Agriculture, Gwalior, Rajmata Vijayaraje Scindia Krishi Vishwa Vidyalaya, Gwalior, M.P., India during July 2019 to December, 2020. Methodology: Five biochemical parameters viz., chlorophyll content, carotenoid content, total soluble sugars, proline and protein were investigated for explanation of differences among 96 pearl millet germplasm lines in respect to drought tolerance. Results: Data of present investigation revealed the mean leaves chlorophyll at 30DAS was 2.90 mgg-1 with the range of 1.31-4.69 mgg-1, whereas chlorophyll at 60DAS was arrayed between 1.46-3.84 mgg-1with an average of 3.02 mgl-1. Carotenoid at 30DAS was ranging from 4.5-11.44 mgg-1 with an average value of 7.23 mgg-1, while carotenoid at 60DAS was recorded in range of 5.01 to 10.10 mgg-1with an average of 6.66 mgg-1. TSS was ranged between 1.10-2.20 mgg-1, proline 0.10 to 0.17 mg g-1 and protein content 9.2-16.60 mgg-1. Conclusions: According to the biochemical data a total of 16 pearl millet genotypes were found to be grouped distantly among all the genotypes. Possibility existed to be drought tolerance of these genotypes.