Levels Of Photosynthetic Pigments Research Articles

Physiological Response, Oxidative Stress Assessment and Aquaporin Genes Expression of Cherry Tomato (Solanum lycopersicum L.) Exposed to Hyper-Harmonized Fullerene Water Complex.

The rapid production and numerous applications of nanomaterials warrant the necessity and importance of examining nanoparticles in terms to their environmental and biological effects and implications. In this study, the effects of a water-soluble hyper-harmonized hydroxyl-modified fullerene (3HFWC) on cherry tomato seed germination, seedlings growth, physiological response and fruiting was evaluated. Changes in the photosynthetic pigments content, oxidative stress assessment, and aquaporin genes expression in cherry tomato plants were studied after during short- and long-term continuous exposure to 3HFWC nanosubstance (200 mg/L). Increased levels of photosynthetic pigments in leaves, lycopene in fruits, decreased levels of hydrogen peroxide content, activation of cellular antioxidant enzymes such as superoxide dismutase, catalase and peroxidase and increased aquaporin gene expression (PIP1;3, PIP1;5 and PIP2;4) were observed in 3HFWC nanosubstance-exposed plants in comparison to control, untreated cherry tomato plants. The 3HFWC nanosubstance showed positive effects on cherry tomato seed germination, plantlet growth and lycopene content in fruits and may be considered as a promising nanofertilizer.

EFFECTS OF DIFFERENT IRRIGATION DEPTHS ON THE CONTENT OF TSH1188 COCOA SEEDLINGS PHOTOSYNTHETIC PIGMENTS

Cacao (Theobroma cacao L.) is a plant whose use is distributed in many different ways, being used for human consumption and as a raw material in the production of chocolate, cocoa powder, jellies, juice pulp, honey and butter. In animal handling, it is associated with the manufacture of feed and can also be used for agricultural production such as the use of fertilizers. Given the expressive importance of the crop, this study aimed to evaluate the effect of different irrigation depths on the levels of photosynthetic pigments in seedlings of TSH 1188 genotype cocoa. For this purpose, five irrigation depths were applied, corresponding to 4, 6, 8, 10 and 12 mm day-1. The experimental design was completely randomized with 20 seedlings per treatment. At 55 days after sowing, photosynthetic pigments were extracted and quantified, and the content of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids was determined. The results were submitted to analysis of variance by the F test at 5% probability. Regression models that best applied to the effects of the irrigation depth on the evaluated characteristics were adjusted. The irrigation depth of 7.74 mm d-1 had the highest total chlorophyll content, being the most recommended for the production of TSH 1188 cocoa seedlings.

Seasonal Changes in the Biochemical Constituents of Green Seaweed Chaetomorpha antennina from Covelong, India.

Seaweeds are well known for having a wealth of nutritional benefits and providing ecological support to associated fauna. Seasonality influences the biochemical characteristics, affecting their ecological and economic values. In the present study, we evaluated pigments, primary and secondary metabolites, minerals, and antioxidant properties of green seaweed Chaetomorpha antennina growing on the intertidal rocks along the Covelong coast, India, in different seasons (from June 2019 to March 2020). Significant variations were found in the levels of antioxidants, minerals, and metabolites in different seasons, e.g., amino acid levels were the highest in post-monsoon and the lowest in summer. In monsoon, we found the highest concentration of fatty acids in the thalli. Lipid peroxidation and total antioxidant activity were at their maximum levels during post-monsoon, which indicated oxidative damage responses. No significant variations were found in the levels of photosynthetic pigments. The outcomes indeed suggested seasonal variations in the biochemical and nutrient profile of C. antennina. We suggest that the harvesting/collection of C. antennina for different nutrients and metabolites should be performed in the respective seasons.

O ácido salicílico alivia o estresse hídrico no aparato fotoquímico e qualidade das mudas de Schinus terebinthifolia

ABSTRACT Water deficit adversely affects photosynthetic pigment synthesis, photochemical processes, and seedling quality. Exogenous foliar application of salicylic acid (SA) is hypothesized to contribute to photochemical regulation and increase stress tolerance. This study aimed to evaluate the effect of SA in alleviating the effects of water deficit stress on the photosynthetic photochemical activities and quality of Schinus terebinthifolia Raddi. seedlings. The seedlings were subjected to four regimes of water deficit: 0, 4, 8, and 12 days of water restriction (DWR), associated with the application of four concentrations of SA: 0, 50, 100, and 200 mg L-1 (via foliar spray; 10 mL per plant) during 48 days. Growth of S. terebinthifolia seedlings was adversely affected by longer duration of water restriction in absence of SA treatment. However, application of 200 mg L-1 of SA increased photosynthetic pigment levels, photochemical quantum efficiency in photosystem II, and absorbed energy conversion efficiency in seedlings under 12 DWR. The seedling quality was better at 7 and 12 DWR when associated with application of 100 and 200 mg L-1 SA, respectively. The exogenous application of SA contributed positively to pigment concentration and photochemical stability of photosynthesis, and it improved the quality of S. terebinthifolia seedlings subjected to long water restriction periods.

SEED PRIMING EFFECTS ON SEED QUALITY AND ANTIOXIDANT SYSTEM IN THE SEEDLINGS OF AMARANTHUS TRICOLOR L.

Amaranthus tricolor L. cv. ‘Valentina’ leaves are a promising source of dietary food supplements (DFS) and are used to prepare tea drinks that improve human health in Russia. Amaranth is a small-seeded crop, and the seed mass differs significantly, which leads to unfriendly shoots and a decrease in the potential productivity of the plant biomass. Pre-sowing treatment with growth stimulants can improve its seed quality. The study aimed to improve the seed quality, the morpho-physiological parameters, and the antioxidant properties of amaranth seedlings grown from seeds treated with plant growth stimulants at the Federal State Budgetary Scientific Institution, Federal Scientific Vegetable Center (FSBSI FSVC), Moscow, Russia. For seed treatments, water solutions of salicylic acid (SA - 138 mg/L), hydrogen peroxide (H2O2 - 5 mM), succinic acid (ScA - 500 mg/L), calcium chloride (CaCl2 - 3000 mg/L), and gibberellic acid (GA3 - 300 mg/L) were used. Researchers germinated the seeds first in petri dishes in natural light at a daytime temperature of 23±2°C for seven days. Determining amaranthine, chlorophyll, and carotenoid content used generally accepted methods. Pre-sowing treatment of large and small fractions of amaranth seeds with GA3, ScA, and CaCl2 improved the seed quality, whereas seed treatment of SA and H2O2 reduced the seed quality. Recording of antioxidants (amaranthine and carotenoids) and total chlorophyll content accumulation in seedlings grown from the treated seeds followed. The levels of amaranthine and photosynthetic pigments decreased in the seedlings of Amaranthus tricolor L. cv. Valentina seeds with ScA, CaCl2, and GA3 treatments, while the seedling's biomass exceeded that of control, which suggests that these chemicals act as growth regulators. The negative effect of SA on the viability of large (LF) and small (SF) amaranth seeds showed significant reductions in the morphometric indicators. It may be due to oxidative stress, enhancing amaranthine content in the cotyledonary leaves of seedlings.

Streptomyces hydrogenans strain DH-16 alleviates negative impact of Meloidogyne incognita stress by modifying physio-biochemical attributes in Solanum lycopersicum plants

The current study assessed the nematicidal and plant growth promoting potential of metabolites produced by Streptomyces hydrogenans strain DH-16 on morphological and physiological activities in 60 days old Solanum lycopersicum plants grown under Meloidogyne incognita stress. M. incognita infestation altered the levels of various photosynthetic pigments, various stress markers, enzymatic and non-enzymatic antioxidants in S. lycopersicum plants grown under in-vivo conditions. However, treatment with culture cells, supernatant and extract produced by S. hydrogenans strain DH-16 significantly reduced the number of galls in M. incognita infested plants when compared with untreated M. incognita infected plants. Moreover, the culture cells/ supernatant/ extract remarkably lowered the levels of stress markers (Hydrogen peroxide and Malondialdehyde) in infected plants and enhanced the activities of non-enzymatic antioxidants (glutathione, tocopherol) and enzymatic antioxidants (Catalase, Superoxide dismutase, Ascorbate peroxidase, Guaiacol peroxidase, Gluatathione-S-transferase and Polyphenol oxidase) in metabolites treated M. incognita infected plants. The enhanced level of different photosynthetic attributes were also evaluated by studying gas exchange parameters and different plant pigments. Moreover, an increment in the content of phenolic compounds such as total phenols, anthocyanin and flavonoids were also reflected in treated and nematode infested plants. The present study also evaluated the microscopic analysis depicting cell viability, nuclear damage and hydrogen peroxide localization in differently treated plants. The outcome of the present study therefore endorses the efficacy of DH-16 as a potential biocontrol agent that help plants in mitigating M. incognita stress.

Microwave Radiation as an Inducer of Secondary Metabolite Production in Drosera rotundifolia In Vitro Plantlets.

In this study, low-intensity microwave irradiation (frequency of 2.45 GHz; 26.3 kW m-3 power density) for 0, 5, and 30 s was tested for the first time on Drosera rotundifolia in vitro plantlets to explore its effect on the production of highly valued phenolic compounds. Analysis of the extracts obtained from irradiated plantlets revealed time-dependent increases in the levels of photosynthetic pigments, particularly the carotenoids, whereas symptoms of growth decline were not observed. Similarly, the highest total antioxidant capacity and total phenolic and flavonoid contents were detected in 30-s-irradiated plantlets. High-performance liquid chromatography analysis revealed that the content of the bioactive phenolics 5-hydroxy-7-methylnaphthalene-1,4-dione (1), 2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one (2), and 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-3-[(3R,4S,5R,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-4-one (3), which are considered to be responsible for the pharmacological properties of this species, was around twofold higher in 30-s-irradiated plantlets than in controls. Nevertheless, the accumulation of 5-hydroxy-2-methylnaphthalene-1,4-dione (4), which was present only in trace amounts in the plant roots, decreased by 30% upon microwave irradiation. The results indicate that microwave treatment acts as an effective inducer of the production of phenylpropanoid compounds, which opens up new opportunities for its use in biotechnological applications.

Toxic mechanism of two cyanobacterial volatiles β-cyclocitral and β-ionone on the photosynthesis in duckweed by altering gene expression

Volatile organic compounds (VOCs) promote cyanobacteria dominating eutrophicated waters, with aquatic plant decrease and even disappearance. To uncover the toxic mechanism of cyanobacterial VOCs on aquatic plants, we investigated the growth, photosynthetic pigment levels, photosynthetic abilities and related gene expression in duckweed treated with β-cyclocitral and β-ionone, 2 main components in the VOCs. The levels of chlorophylls and carotenoids gradually declined with raising the concentration of the 2 compounds and prolonging the treatment time. Their decline should result from the down-regulation of 8 genes associated with photosynthetic pigment biosynthesis and up-regulation of 2 genes involved in carotenoid degradation. The reduction was also found in the photosystem II (PSII) efficiency and O2 evolution rate, which should result from the lowered photosynthetic pigment levels and down-regulation of 38 genes related with photosynthetic process. The frond numbers, total frond area and fresh weight gradually decreased with raising the 2 compound concentration, which may result from the lowered photosynthetic abilities as well as down-regulated expression of 7 genes associated with growth-promoting hormone biosynthesis and signal transduction. It can be speculated that cyanobacterial VOCs may poison aquatic plants by lowering the photosynthesis and growth through altering related gene expression.

Sunflower Bark Extract as a Biostimulant Suppresses Reactive Oxygen Species in Salt-Stressed Arabidopsis.

A survey of plant-based wastes identified sunflower (Helianthus annuus) bark extract (SBE), produced via twin-screw extrusion, as a potential biostimulant. The addition of SBE to Arabidopsis (Arabidopsis thaliana) seedlings cultured in vitro showed a dose-dependent response, with high concentrations causing severe growth inhibition. However, when priming seeds with SBE, a small but significant increase in leaf area was observed at a dose of 0.5 g of lyophilized powder per liter. This optimal concentration of SBE in the culturing medium alleviated the growth inhibition caused by 100 mM NaCl. The recovery in shoot growth was accompanied by a pronounced increase in photosynthetic pigment levels and a stabilization of osmotic homeostasis. SBE-primed leaf discs also showed a similar protective effect. SBE mitigated salt stress by reducing the production of reactive oxygen species (ROS) (e.g., hydrogen peroxide) by about 30% and developing more expanded true leaves. This reduction in ROS levels was due to the presence of antioxidative agents in SBE and by activating ROS-eliminating enzymes. Polyphenols, carbohydrates, proteins, and other bioactive compounds detected in SBE may have contributed to the cellular redox homeostasis in salt-stressed plants, thus promoting early leaf development by relieving shoot apical meristem arrest. Sunflower stalks from which SBE is prepared can therefore potentially be valorized as a source to produce biostimulants for improving salt stress tolerance in crops.

Synergism between Streptomyces viridosporus HH1 and Rhizophagus irregularis Effectively Induces Defense Responses to Fusarium Wilt of Pea and Improves Plant Growth and Yield.

Fusarium wilt is a detrimental disease of pea crop, resulting in severe damage and a reduction in its yield. Developing synergistically enhanced bioagents for disease management and growth promotion is pivotal for food safety, security, and sustainability. In this study, biocontrol potential of treating pea plants with Streptomyces viridosporus HH1 and/or their colonization with Rhizophagus irregularis against infection with Fusarium wilt was investigated. Impacts on the expression profiles of defense-related genes, biochemical, and ultrastructural levels, as well as the growth and yield of pea plants in response to these treatments, were also investigated. Data obtained indicated the antifungal activity of S. viridosporus HH1 against F. oxysporum f.sp. pisi in vitro. Furthermore, the GC-MS analysis revealed production of different bioactive compounds by S. viridosporus HH1, including 2,3-butanediol, thioglycolic acid, and phthalic acid. The results from the greenhouse experiment exhibited a synergistic biocontrol activity, resulting in a 77% reduction in disease severity in pea plants treated with S. viridosporus HH1 and colonized with R. irregularis. In this regard, this dual treatment overexpressed the responsive factor JERF3 (5.6-fold) and the defense-related genes β-1,3-glucanase (8.2-fold) and the pathogenesis-related protein 1 (14.5-fold), enhanced the total phenolic content (99.5%), induced the antioxidant activity of peroxidase (64.3%) and polyphenol oxidase (31.6%) enzymes in pea plants, reduced the antioxidant stress, and improved their hypersensitivity at the ultrastructural level in response to the Fusarium wilt pathogen. Moreover, a synergistic growth-promoting effect was also recorded in pea plants in response to this dual treatment. In this regard, due to this dual treatment, elevated levels of photosynthetic pigments and improved growth parameters were observed in pea leaves, leading to an increment in the yield (113%). In addition, application of S. viridosporus enhanced the colonization levels with R. irregularis in pea roots. Based on the obtained data, we can conclude that treating pea plants with S. viridosporus HH1 and colonization with R. irregularis have synergistic biocontrol activity and growth-promoting effects on pea plants against Fusarium wilt. Despite its eco-safety and effectiveness, a field evaluation of this treatment before a use recommendation is quite necessary.

Effects of glutathione on waterlogging-induced damage in sesame crop

Sesame (Sesamum indicum) is an important oil crop, occupying the seventh position in the edible oil industry; however, it is relatively sensitive to waterlogging (WL) stress. Reduced glutathione (GSH) is known to have mitigating effects against various abiotic stresses in plants; however, its exploration to improve WL tolerance in sesame is still elusive. In this study, we investigated the multiple effects of exogenously applied GSH in sesame plants subjected to WL for 3 days. Our results showed improvement in growth and biomass production of GSH-sprayed waterlogged sesame when compared with WL-stressed counterpart alone. The improved performance of GSH-sprayed WL-stressed plants was supported by the increased leaf area, the levels of photosynthetic pigments and gas exchange attributes, and chlorophyll fluorescence parameters. Exogenous GSH treatment significantly increased the levels of total soluble sugars and total free amino acids in the leaves of sesame plants for the improvement of water balance under WL conditions. Accumulations of superoxide and hydrogen peroxide, enhancement of malondialdehyde level, and electrolyte leakage in sesame leaves indicated evident oxidative damage induced by WL. On the other hand, exogenous GSH application diminished oxidative stress by enhancing the activities of catalase, ascorbate peroxidase, peroxidase, glutathione peroxidase, and glutathione S-transferase, as well as total flavonoid and GSH levels in the leaf tissues. Furthermore, GSH supplementation to WL plants increased the transcript levels of numerous antioxidant defense-related genes, such as SiCAT1, SiCATX1, SiAPX3, SiPOD40, SiPOD44, SiGPX4, SiPHGPX1, SiGSTU23, and SiGSTU25 in shoots, corresponding to enhanced activities of respective antioxidant enzymes. Our results highlight the potential roles of GSH in modulating adaptive mechanisms of sesame plants for reduction of WL-induced damage, and this GSH-mediated effective strategy could be implemented at the field level to sustain sesame production under WL conditions.

Physiological mechanisms of ABA-induced salinity tolerance in leaves and roots of rice

Abscisic acid (ABA) plays a crucial role in response to abiotic stress as important small molecules in regulating metabolism. This study aimed to evaluate the ability of foliar spraying ABA to regulate growth quality at rice seedling stage under salt stress. Results demonstrated that salt stress strongly reduced all the growth parameters of two rice seedlings (‘Chaoyouqianhao’ and ‘Huanghuazhan’), caused prominent decrease in the levels of photosynthetic pigments (mainly in Huanghuazhan), photosynthesis and fluorescence parameters. Salinity treatment increased the concentration of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in roots, whereas significant decreased H2O2 was found in leaves of Huanghuazhan. Additionally, salinity triggered high Na+ content particularly in leaves and enhanced catalase (CAT) activities, ascorbate peroxidase (APX) and peroxidase (POD) activities of the two rice seedlings. Nevertheless, salinity-induced increased root ascorbic acid (AsA) and glutathione (GSH) levels while decreased in leaves, which depended on treatment time. Conversely, ABA application partially or completely mitigated salinity toxicity on the seedlings. ABA could reverse most of the changed physiological parameters triggered by salt stress. Specially, ABA treatment improved antioxidant enzyme levels and significantly reduced the Na+ content of two varieties as well as increased the K+, Mg2+ and Ca2+ content in leaves and roots. ABA treatment increased the hormone contents of 1-aminocclopropane carboxylic acid (ACC), trans-zeatin (TZ), N6-isopentyladenosine (IPA), Indole-3-acetic acid (IAA), and ABA in leaves of two rice varieties under salt stress. It is suggested that ABA was beneficial to protect membrane lipid peroxidation, the modulation of antioxidant defense systems and endogenous hormonal balance with imposition to salt stress.

Integrated physiological, transcriptomic and metabolomic analysis of the response of Trifolium pratense L. to Pb toxicity

Lead (Pb) interferes with plant gene expression, alters metabolite contents and affects plant growth. However, the molecular mechanism underlying the plant response to Pb is not completely understood. In the present study, Trifolium pratense L. was exposed to Pb concentrations of 0 (Pb0), 500 (Pb500), 1000 (Pb1000), 2000 (Pb2000) and 3000 (Pb3000) mg/kg in soils. Pb stress affected the ability of T. pratense to accumulate and transport Pb, increased the activity of peroxidase (POD) and the contents of malondialdehyde (MDA) and proline, decreased the amount of photosynthetic pigments and soluble proteins, and led to changes in growth and biomass. Transcriptomic and metabolomic analyses showed that Pb mainly affected eight pathways, and LHC, flavonoids, organic acids, amino acids and carbohydrates were upregulated or downregulated. Moreover, Pb500 induced the upregulation of serA, promoted the synthesis of citric acid, maintained photosynthetic pigment levels, and ultimately promoted an increase in stem length. Pb3000 induced the upregulation of ARF, GH3 and SAUR genes, but the saccharide contents and stem length decreased in response to Pb stress. We used a variety of methods to provide a molecular perspective on the mechanism underlying the response of T. pratense to Pb stress.

Measurement of Photosynthetic Pigment Content using Convolutional Neural Network

Estimation of photosynthetic pigment levels from leaves can be done using conventional methods using laboratory equipment such as spectrophotometers and using digital image processing from leaf images with a computational model. In digital image processing methods, various models are used, such as neural network, CNN, and linear regression. Measurement of photosynthetic pigment levels using image processing methods uses color value data from image data as input to the model used. In this study, we will analyze the effect of various types of color space and inpaint preprocessing settings on the accuracy of the CNN model in measuring leaf photosynthetic pigment levels. The color space types being tested are 4 single color spaces RGB, HSV, LAB, and YCbCr, as well as 6 color combination spaces RGB+HSV, RGB+LAB, RGB+YCbCr, HSV+LAB, HSV+YCbCr, and LAB+YCbCr. The choice of the type of color space takes into account the phenomenon of color constancy and the characteristics of the color space on the lighting elements. In addition, image data is divided into two types, namely through inpaint preprocessing and not, so that in total there are 20 types of input data. After the CNN model training process with various types of color spaces and different preprocessing settings as input data, observations were made on the accuracy values, namely the training MAE and the validation MAE for each model. From 20 types of input data, 3 types of input data are obtained which are recommended as input data that provide the best model accuracy value based on MAE validation with values ​​of 0.08761, 0.09252, and 0.09288. The three recommended input data from the sequence of accuracy values ​​are RGB+LAB without inpaint, RGB with inpaint, and LAB+YCbCr without inpaint.

Growth and physiological responses of cabbage cultivars biofortified with inorganic selenium fertilizers

Selenium (Se) is essential for humans and animals. Problems associated with Se deficiency in the population diets is spread throughout the world and its related to low Se concentration in the foods. This study aimed to evaluate the effectiveness of different sources and Se concentration on agronomic biofortification of cabbage and its effects on nutritional and photosynthetic parameters. Two cabbage cultivars were treated with five Se concentrations (0, 5, 15, 30 and 60 μM) and two sources (selenate and selenite). The concentration of Se in the cabbage heads increased continuously up to 60 μM, but with no effect on the N, P and S concentrations. At low Se concentration (5 μM), there was an increase in the net photosynthesis, stomata conductance, intern carbon concentration and transpiration, besides increases in photosynthetic pigment levels, which led to an increase of over 100% in head dry mass and yield. The cultivars responded differently to the treatments, but both were highlighting the efficiency of Se fertilization in the heads. Both chemical forms of Se can be used at low concentrations (5 and 15 μM) for the agronomic biofortification of cabbage, however, selenite demonstrated to be most efficient.

Zinc Supplementation Enhances Glutathione-Mediated Antioxidant Defense and Glyoxalase Systems to Conferring Salt Tolerance in Soybean (Glycine max L.)

In this study, the role of zinc (Zn) in salt-affected soybean (Glycine max L.) was scrutinized by exposing plants to salt stress (150 mM NaCl) alone and in combination with exogenous Zn (priming and/or foliar spray with 1 mM ZnSO4.7H2O). Salt stress decreased plant growth and caused the destruction of chlorophyll and carotenoids. It also disrupted physiological processes and antioxidant defenses, resulting in an oxidative burst. The levels of the toxic metabolite methylglyoxal (MG) rose substantially under salinity. Salinity resulted in a high accumulation of Na+ and decreased K+ which decreased the K+/Na+ ratio. Zn supplementation decreased ion toxicity and improved ion homeostasis in soybean plants. Zn increased glutathione (GSH) levels, decreased glutathione disulfide levels, and increased their ratio in salt-treated soybean plants compared to salt-treated plants without Zn addition. Zn supplementation also upregulated the activities of the glutathione-dependent enzymes glutathione reductase, dehydroascorbate reductase, glutathione peroxidase, and glutathione S-transferase in salt-stressed plants. The enhanced GSH pool and increased activity of GSH-dependent enzymes decreased oxidative damage, as indicated by the reduced levels of H2O2 and malondialdehyde and lower electrolyte leakage. The increased GSH level and high activity of glyoxalase I and glyoxalase II conferred by Zn under salt stress helped to scavenge methylglyoxal. The restoration of photosynthetic pigment levels and increased proline accumulation, together with the recovery of leaf relative water content, were further signs of salt stress recovery and tolerance conferred by Zn supplementation. Our results showed that the antioxidant defense, glyoxalase system and some other physiological parameters were improved by Zn supplementation which contributed to mitigating the effects of salt stress in soybean.

Vermicompost leachate, seaweed extract and smoke-water alleviate drought stress in cowpea by influencing phytochemicals, compatible solutes and photosynthetic pigments

Drought is a major constraint for agricultural production worldwide and is likely to become aggravated by global warming. It can induce land degradation, exorbitant food prices and menace livelihoods. Approaches for retaining optimal yield, especially in rainfed staple crops such as cowpea [Vigna unguiculata (L.) Walp] are paramount. Biostimulants vermicompost leachate (VCL), seaweed extract [Kelpak® (KEL)] and smoke-water (SW) have exhibited effective amelioration for plants under abiotic stresses, however, research on cowpea remains scarce. Therefore, this study aimed to investigate the effects of seed priming of cowpea with VCL, KEL and SW on the growth, photosynthesis and biochemical levels in cowpea cultivated under three watering regimes. SW treatment amplified growth variables (i.e., shoot height, root length and number of flowers) of water-stressed cowpeas. KEL- and VCL-treatment of seeds significantly augmented shoot and nodule production by 2- and 4-fold respectively, compared to the control. Leaf carbohydrates and photosynthetic pigments in KEL- and SW-treated plants increased considerably under severe water deficits, while leaf proteins decreased by more than 3-fold. The biostimulants also lowered phenolic and flavonoid concentrations. Increasing and decreasing levels of soluble sugars, proteins, photosynthetic pigments, phenolics and flavonoids indicate stress alleviation and osmotic adjustment to water deficits. These biostimulants are a suitable alternative to improve soil fertility, growth, and yield of staple crops under water stress conditions.

Gas exchange and morphometric characteristics of basil according to the times and collection positions in the plant

The productive potential of plant species depends on the genotype versus environment interaction, so the choice of cultivar is decisive for the success of the crop. Thus, the objective of this work was to evaluate the levels of photosynthetic pigments and morphometric characteristics of two cultivars of green and red basil as a function of the collection time and different collection positions in the plant, as well as the gas exchange in response to variation of the flux density of photosynthetically active photons. The experiment was carried out in a protected environment with a randomized block design in a 2 x 3 x 3 factorial scheme containing 2 treatments consisting of two basil cultivars (alfavaca basilicão, red and green) and fifteen replications. The first factor was constituted by the cultivars, the second, by the time of collection, and the third, by the positions in which the collections were carried out on the plant. For evaluations of morphometric variables and gas exchange rates, the two cultivars were compared. Basil has photosynthesis saturation at radiation rates of about 1500 μmol m-2 s-1. The green colored cultivar was more productive, in addition to having the highest levels of chlorophyll a, b and total, and lower rate of leaf transpiration in response to photosynthetically active photons flow density, adapted for greater carboxylation efficiency and water use.

Photosynthetic pigments in maize (Zea mays) vis-Ã -vis biological performance and host selection by Sesamia inferens

In the present study, host selection behaviour and biological performance of Sesamia inferens on different maize (Zea mays L.) genotypes was investigated in 2018–19, and constitutive and insect damage-induced levels of various photosynthetic pigments were determined. There were significant differences in larval period, larval survival, larval weight, pupal period, pupal weight, adult emergence, and fecundity of S. inferens on the test maize genotypes. The S. inferens that fed on maize genotypes, viz. CPM 2, CPM 4, CPM 8, CPM 15 and CML 345 showed significant increase in developmental period, decrease in larval weight, and reduced larval survival, adult emergence and fecundity as compared to other test genotypes. The S. inferens larval recovery and preference were significantly lower, while the larvae took longer time to establish in the whorls of CPM 2, CPM 15 and CML 345 as compared to other test maize genotypes. The chlorophyll A, chlorophyll B and total chlorophyll content varied significantly in the seedlings of different maize genotypes, under healthy and S. inferens damaged conditions (except, chlorophyll B), while the genotype × treatment interactions were non-significant. The differences for total carotenoids were non-significant. The S. inferens infestation reduced these photosynthetic pigments in the seedlings of all test maize genotypes, except Basi Local, with lowest reduction in CPM 2. The study suggests that the maize genotypes, viz. CPM 2, CPM 4, CPM 8, CPM 15 and CML 345 have greater detrimental effects on the development, survival and fecundity of S. inferens, and can be used in maize improvement program.

Determination of some physiological parameters in spinach (Spinacia oleracea L.) cultivated in Kosovo

Summary The objective of this work was to investigate the levels of photosynthetic pigments, antioxidant enzyme activities (superoxide dismutase [SOD], catalase [CAT], peroxidase [POX], ascorbate peroxidase [APX], glutathione reductase [GR], and MDA), total glutathione (GSH), total ascorbate (AsA), and lipid peroxidation of two spinach cultivars (Clipper and Matador) sampled in different locations in Kosovo (Prizren, Ferizaj, and Obiliq). The photosynthetic pigments, chlorophyll a and b as well as carotenoids, were extracted by 80% acetone, and concentrations were calculated based on the absorbance values at 663, 645, and 480 nm. There was a significant difference in SOD, APX, and GR activities between varieties at each location. The MDA and AsA contents in Obiliq were the highest, compared to other locations. From the increase in lipid peroxidation level, it can be assumed that the degradation in pigment content was caused by the decrease in total AsA content and APX and GR enzyme activities, which are the main enzymes of the AsA–GSH cycle in chloroplasts.