Evaluation of Cadmium Bioaccumulation-Related Physiological Effects in Salvinia biloba: An Insight towards Its Use as Pollutant Bioindicator in Water Reservoirs

Free-living macrophytes play an important role in the health of aquatic ecosystems. Therefore, the use of aquatic plants as metal biomonitors may be a suitable tool for the management of freshwater reservoirs. Hence, in this study, we assessed the effects of cadmium (Cd) in Salvinia biloba specimens collected from the Middle Paraná River during a 10-day experiment employing artificially contaminated water (100 μM Cd). S. biloba demonstrated a great ability for Cd bioaccumulation in both the root-like modified fronds (named “roots”) and the aerial leaf-like fronds (named “leaves”) of the plants. Additionally, Cd toxicity was determined by the quantification of photosynthetic pigments (chlorophylls a and b, and carotenoids), flavonoids, and soluble carbohydrate contents in S. biloba over time (1, 3, 5, 7, and 10 days). In general, deterioration was more pronounced in leaves than in roots, suggesting a greater implication of the former in long-term Cd sequestration in S. biloba. Deleterious effects in the appraised parameters were well correlated with the total amount of Cd accumulated in the leaves, and with the qualitative changes observed in the plants’ phenotype during the 10-day metal exposure assay. The flavonoids and carotenoids in leaves were highly affected by low Cd levels followed by root carbohydrates. In contrast, chlorophylls and root flavonoids were the least impacted physiological parameters. Therefore, our results demonstrate that S. biloba displays dissimilar organ-linked physiological responses to counteract Cd phytotoxicity and that these responses are also time-dependent. Though further research is needed, our work suggests that easy-handled physiological data obtained from autochthonous free-floating S. biloba specimens may be used as a valuable tool for metal-polluted water biomonitoring.

Assessment of the effect of heavy metal salts on the photosynthetic activity of aquatic plants

The status of the photosynthetic pigments in the aquatic plants Lemna minor L. and Elodea canadensis Michx. under the action of Ni2+, Co2+, Cu2+ and Pb2+ acetate in concentrations 5.00, 2.50, 1.25, 0.62, 0.31, 0.15, 0.07, and 0.03 mg/L was assessed by changes in the fluorescence intensity of chlorophyll a and b and their ratio. It was established that nickel acetate in original solutions in all the above concentrations caused an increase in the fluorescence intensity of chlorophylls a and b in L. minor in relation to the control while the lead salt suppressed it. Co2+ acetate inhibits the fluorescence of chlorophyll a with concentrations in the initial solutions of 0.03 to 0.15 and 2.50 mg/L and that of chlorophyll b at all concentrations, except 0.62, 1.25 and 2.50 mg/L. For E. canadensis it was found that the salts of all metals at all concentrations caused a reduction of the fluorescence intensity of chlorophyll a relative to the control and increased it in the case of chlorophyll b. The exception is the effect of copper and lead acetates with a concentration of 1.25 mg/L, when the fluorescence intensity of chlorophyll b is maintained at the control level. The presence of Ni2+, Co2+, Cu2+, and Pb2+ acetates in all concentrations in the culture medium influences the quantitative and qualitative characteristics of chlorophyll a and b, which indicates a violation of the photosynthesis process. Our data on the change in the chlorophyll a / b ratio leads to a conclusion about degradation of chlorophyll a relative to chlorophyll b after the effect of heavy metals.

Comparative study of photosynthetic pigments in the leaves of forage plants of the cryolithozone of Yakutia

Thin-layer chromatography and spectrophotometry were used to determine the content of photosynthetic pigments (chlorophylls a and b, carotenoids) in green leaves of forage plants. It was found that the content of carotenoids was high for forage grasses with a high content of green pigments. It was revealed that β-carotene plays the most important role since it is a precursor of vitamin A and lutein, which has a high antioxidant (protective) property. According to modern concepts, lutein and β-carotene actively function in various organs of herbivores. They play a special role in the functioning of the mammalian visual apparatus, protecting this organ from the light factor. In addition, lutein is one of the physiologically active substances that make up cow’s milk.

Removal of pentachlorophenol from contaminated wastewater using phytoremediation and bioaugmentation processes

The phytoremediation procedure was conducted by Lemna gibba (L) and Typha angustifolia (T) and the bioaugmentation procedure used P. putida HM627618. The ability of the selected P. putida HM627618 to tolerate and remove PCP (200 mg L−1) was measured by high performance liquid chromatography analysis and optical density at 600 nm. Five different experiments were conducted in secondary treated wastewater for PCP testing removal (100 mg L−1) including two phytoremediation assays (T + PCP; L + PCP), three bioaugmentation-phytoremediation assays (T + B + PCP; L + B + PCP; L + T + B + PCP) and a negative control assay with PCP. Various analytical parameters were determined in this study such as bacterial count, chlorophylls a and b, COD, pH and PCP content. The main results showed that the average PCP removal by P. putida HM627618 was around 87.5% after 7 days of incubation, and 88% of PCP removal was achieved by treatment (T + B) after 9 days. During these experiments, pH, COD and chloride content showed a net increase in all treatments. The chlorophylls a and b in case of (T) and (L) Chlorophylls a and b for T and L phytoremediation showed a decrease with a value less than 10 μg/mg of fresh material after 20 days of cultivation.

Attenuation of salt stress on the physiology and production of bell peppers by treatment with salicylic acid

The use of saline water for irrigation in semi-arid regions has become a reality due to the water scarcity that occurs in most of the year. In this scenario, exogenous application of salicylic acid may be a strategy to mitigate the deleterious effects of salt stress on plants and ensure the production of socioeconomically important crops in the semiarid region of Northeast Brazil, such as bell pepper. Thus, this study examines the osmoprotective effect of salicylic acid on gas exchanges, chloroplast pigments and production components of ‘All Big’ bell pepper plants irrigated with water with different saline levels. The experiment was carried out in greenhouse conditions in Campina Grande - PB, Brazil. Treatments consisted of four levels of electrical conductivity on the irrigation water (0.8, 1.6, 2.4 and 3.2 dS m-1) and four concentrations of salicylic acid (0, 1.2, 2.4 and 3.6 mM), which were distributed in a 4 × 4 factorial arrangement in a randomized block design with three replicates. Increases in irrigation water salinity from 0.8 dS m-1 resulted in changes in gas exchange and total chlorophyll levels of ‘All Big’ bell pepper plants. The estimated salicylic acid concentration of 1.7 mM reduced the effects of salinity on stomatal conductance, transpiration, CO2 assimilation rate, instantaneous carboxylation efficiency, total chlorophyll and fruit diameters. Irrigation with water of 1.8, 0.8 and 1.6 dS m-1 salinity associated with the estimated salicylic acid concentration of 1.6 mM increased the biosynthesis of chlorophylls a and b and the number of fruits, respectively, in bell pepper plants.

ASPECTOS BIOQUÍMICOS E FLUORESCÊNCIA DA CLOROFILA A EM PLANTAS DE MINIMELANCIA HIDROPÔNICA SOB ESTRESSE SALINO*

ASPECTOS BIOQUÍMICOS E FLUORESCÊNCIA DA CLOROFILA A EM PLANTAS DE MINIMELANCIA HIDROPÔNICA SOB ESTRESSE SALINO* LAÍS MONIQUE GOMES DO Ó1, ALIDE MITSUE WATANABE COVA2, PETTERSON COSTA CONCEIÇÃO SILVA3, HANS RAJ GHEYI4, ANDRÉ DIAS DE AZEVEDO NETO5, ROGÉRIO FERREIRA RIBAS6 1Doutoranda em Engenharia Agrícola da Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, s/n, Cruz das Almas, Bahia, Brasil [email protected]. 2Pós-Doutoranda no Programa de Pós-graduação de Engenharia Agrícola da Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, s/n, Cruz das Almas, Bahia, Brasil, [email protected]. 3Doutor em Engenharia Agrícola, Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, s/n, Cruz das Almas, Bahia, Brasil, [email protected]. 4Professor Visitante, Universidade Federal do Recôncavo da Bahia, Cruz das Almas, Bahia, [email protected]. 5Professor Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, s/n, Cruz das Almas, Bahia, Brasil, [email protected]. 6Professor Universidade Federal do Recôncavo da Bahia, Rua Rui Barbosa, s/n, Cruz das Almas, Bahia, Brasil, [email protected]. *Este artigo é proveniente da tese de doutorado do primeiro autor. 1 RESUMO A salinidade é um dos principais estresses abióticos que induz distúrbios bioquímicos e fisiológicos em diversas culturas. O objetivo do trabalho foi investigar os efeitos da salinidade da solução nutritiva (CEsol) sobre a produção, acúmulo de solutos orgânicos e inorgânicos e fluorescência da clorofila a em plantas de minimelancia cv. Sugar Baby. O delineamento experimental foi o inteiramente casualizado com quatro repetições. As plantas foram cultivadas em sistema hidropônico com cinco níveis de CEsol: 2,5; 3,5; 4,5; 5,5 e 6,5 dS m-1. Foram avaliados: massa do fruto, biomassa da parte aérea, teores de clorofilas a e b, fluorescência da clorofila a e teores de solutos orgânicos e inorgânicos. A massa do fruto e a biomassa seca da parte aérea foram influenciadas negativamente pela CEsol. Houve redução na concentração de carboidratos solúveis totais, aminoácidos livres, proteínas solúveis e prolina livre com o aumento da CEsol. Os íons sódio, cloreto e razão sódio/potássio aumentaram com a salinidade e os teores de potássio foram reduzidos. O incremento da salinidade aumentou linearmente o teor de clorofila b e reduziu linearmente o rendimento quântico da conversão de energia fotoquímica do FSII promovendo um ligeiro aumento no rendimento quântico da perda de energia regulada do FSII. Palavras-chaves: biomassa, carboidratos, íons tóxicos, estresse abiótico. Ó, L. M. G.; COVA, A. M. W.; SILVA, P. C. C.; GHEYI, H. R.; AZEVEDO NETO, A. D. de; RIBAS, R. F. BIOCHEMICAL ASPECTS AND CHLOROPHYLL A FLUORESCENCE IN HYDROPONIC MINI WATERMELON PLANTS UNDER SALT STRESS 2 ABSTRACT Salinity is one of the main abiotic stresses that induce biochemical and physiological disorders in diverse crops. This study investigated the effects of nutrient solution salinity (ECsol) on production, accumulation of organic and inorganic solutes and chlorophyl a fluorescence in mini watermelon plants cv. Sugar Baby. The experimental design was completely randomized with four replications. The plants were grown in a hydroponic system with five levels of ECsol: 2.5; 3.5; 4.5; 5.5 and 6.5 dS m-1. The variables evaluated were the mass of the fruit, the biomass of the aerial parts, contents of chlorophylls a and b, fluorescence of chlorophyll a, and contents of organic and inorganic solutes. The mass of the fruit and dry biomass of the aerial parts was negatively influenced by ECsol. There was a reduction in the concentration of total soluble carbohydrates, free amino acids, soluble proteins and free proline with the increase in ECsol. The sodium, chloride and sodium/potassium ratio increased with ECsol and potassium levels were reduced. The increase in ECsol linearly increased the chlorophyll b content and reduced the quantum yield of the photochemical energy conversion of the PSII promoting a slight increase in the quantum yield of the regulated energy loss of the PSII. Keywords: abiotic stress, biomass, carbohydrates, toxic ions.

Antioxidant Properties of Fruit and Vegetable Whey Beverages and Fruit and Vegetable Mousses

The study assesses the antioxidant activity, total phenolic content, total flavonoids content and lipophilic pigments (β-carotene, chlorophyll a, chlorophyll b) content in homemade and marketed fruit and vegetable whey beverages and fruit and vegetable mousses. All of the tests were performed using spectrophotometric methods. The highest polyphenol content was found in the homemade green whey beverage W1G (541.95 mg/100 g) and the lowest in the market green whey beverage W2G (46.18 mg/100 g). In the fruit and vegetable mousses under study, the highest content of polyphenolic compounds was determined in the red mousse R3 (76.41 mg/100 g). The highest content of flavonoids was observed in the homemade orange whey beverage W1O (63.06 mg/100 g) and in the green mousse G2 (69.80 mg/100 g). The values of the antioxidant activity of whey beverages and mousses varied depending on the composition. The highest content of β-carotene was identified in homemade orange whey beverage (4.36 mg/100 g) and in orange mousses (in range 1.10–2.24 mg/100 g), while chlorophylls a and b—in homemade green whey beverage W1G (3.00 mg/100 g and 1.31 mg/100 g respectively) and in green mousses (chlorophyll a in range 0.54 to 1.42 mg/100 g and chlorophyll b in range 0.13 to 0.32 mg/100 g).

Study of cherry agrobiological and biochemical values depending on the breeding method

In 2018–2020, in the Federal Research Centre of Horticulture in the Leninsky district of the Moscow region, a research study into the growth, production and biochemical processes of ungrafted and grafted cherry trees was performed. The planting plan was 5×2.5 m, the age of the trees — 17-19 years. Three varieties of cherries (Rusinka, Volochaevka, Apukhtinskaya), grafted on clonal rootstock (AVCH-2, Moskoviya Izmailovskiy) and own-root, propagation-grown by herbaceous cuttings, were selected as the study objects. Biochemical studies involved determining the total antioxidant status of the alcoholic extract, the chlorophylls (a and b) and carotenoids content, the total of phenolic compounds, rutin and quercetin in the leaves. The study aimed to assess the agrobiological and biochemical parameters of grafted and own-root cherry varieties and to identify the optimal growing technique for promising ones. It was found that the variety, rootstock and breeding method influenced the growth and development of cherry trees. The linear and radial growth improved for the trees grafted on the AVC-2 and Moskoviya rootstocks and the height and crown volume thinned for the own-root trees and in those grafted on the Izmailovskiy rootstock. Depending on the variety, stock and growing technique of seedlings, the productivity of trees ranged from 3.5 (Rusinka, own-root) to 11.6 kg/tree (Apukhtinskaya, own-root). The advantage of own-root trees compared to grafted ones was revealed for Apukhtinskaya and Volochaevka varieties. The Rusinka variety showed the highest productivity when grafted on the Izmailovsky rootstock (5.5 kg/tree). To increase the yield per garden when cultivating the Apukhtinskaya and Volochaevka varieties, it is beneficial to use own-root seedlings grafted on the Moskoviya and Izmailovskiy rootstocks. For the Rusinka variety, the optimal result can be achieved when growing seedlings grafted on the Izmailovsky rootstock. The biochemical studies allowed the influence of rootstock on the photosynthetic, antioxidant systems and the synthesis of phenol compounds in the cherry leaves to be determined. It was shown that the antioxidant activity and the accumulation of phenol compounds in the leaves were the highest for the own-root plants of the most winter-hardy Rusinka variety and the Rusinka/Izmailovskiy graftedrootstock combination. The chlorophyll and carotenoid contents were the highest in the leaves of the Apukhtinskaya variety own-root trees, Apukhtinskaya/Izmailovskiy and Rusinka/Izmailovskiy grafted-rootstock combinations with increased productivity. Notably, the biochemical values decreased for all varieties grafted on the AVC-2 rootstock.

Lipid Extracts from Caulerpa lentillifera Waste: An Alternative Product in a Circular Economy

Nowadays, a circular economy is one of the main strategies for developing a sustainable economy. The objective of this work was to increase the value of Caulerpa lentillifera waste and use it efficiently as a resource for lipid extraction. A crude lipid yield of approximately 27.69% of the dry weight was obtained under the following optimized conditions that consisted of a three-stage extraction with 15 min/stage using a ratio of 1:10 (w/v) at room temperature. The crude extracts contained a total fatty acids (TFA) content of approximately 58.60% of the weight of the extracts, which consisted of 10 types of fatty acids. The proportion of palmitic acid (16:0) as the main component was above 70% of the TFA content. Moreover, it also contained chlorophylls a and b and carotenoids at approximately 1.77, 0.91, and 0.70 µg/mg of the extract, respectively. The total phenolic and flavonoids content, including 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 1,1′- diphenyl-2-picrahydrazyl (ABTS and DPPH, respectively) scavenging activities, showed that the lipid extracts had high potential for antioxidant activity. Moreover, the extracts also demonstrated α-glucosidase inhibitory activity with an IC50 value of 8.97 mg/mL. Thus, this extract could be used as an alternative product in a circular economy for preventing diabetes disease.

Correlation analysis of the parameters of oats assimilation apparatus and productivity elements

On sod-podzolic soils, new data is obtained on the functioning of the photosynthetic structures of oat leaves in various climatic conditions and of biomass accumulation (plant productivity). Based on three-year data (2015-2017) of field experiments with 29 oat genotypes, the relationship between the development of productivity elements and the characteristics of the plant assimilation apparatus is analyzed. The pigment content (chlorophyll a, chlorophyll b, carotenoids) was evaluated in acetone extracts on a UVmini-1240 spectrophotometer (SHIMADZU Corporation, Japan). Statistically significant correlations were established between the total leaf surface area and grain mass per plant (r = 0.664), the number of spikelets in a panicle, grain mass per panicle and the mass of the panicle itself (r = 0.548 ... 0.613). These correlations decreased during a drought and increased in conditions of excessive moisture. Oat genotypes with a larger sub-flag leaf had a larger panicle, with a large number of spikelets, grains and of larger grain mass per panicle and plant. During a drought, these correlations decreased. The correlation of the flag leaf area with the grain mass of the panicle and plant under stressful conditions of excessive moisture or a drought increased. With excessive moisture, an increase in the proportion of chlorophyll a in the total chlorophyll pool and in the composition of the reaction centers of photosystems was observed in genotypes with an increased number of spikelets and grains in a panicle, with larger grain masses per panicle and plant, and a mass of 1000 grains. During a drought, the correlation of the content of chlorophylls a and b increased with the following signs: panicle length, panicle mass, number of spikelets in a panicle, and number of grains in a panicle. However, an increase in panicle mass and the number of grains in it was accompanied by a decrease in the proportion of chlorophyll a in the total pigment pool and in the composition of reaction centers.