Chromium (Cr) toxicity significantly threatens agricultural ecosystems worldwide, adversely affecting plant growth and development and reducing crop productivity. Trehalose, a non-reducing sugar has ...been identified as a mitigator of toxic effects induced by abiotic stressors such as drought, salinity, and heavy metals. The primary objective of this study was to investigate the influence of exogenously applied trehalose on maize plants exposed to Cr stress.BACKGROUNDChromium (Cr) toxicity significantly threatens agricultural ecosystems worldwide, adversely affecting plant growth and development and reducing crop productivity. Trehalose, a non-reducing sugar has been identified as a mitigator of toxic effects induced by abiotic stressors such as drought, salinity, and heavy metals. The primary objective of this study was to investigate the influence of exogenously applied trehalose on maize plants exposed to Cr stress.Two maize varieties, FH-1046 and FH-1453, were subjected to two different Cr concentrations (0.3 mM, and 0.5 mM). The results revealed significant variations in growth and biochemical parameters for both maize varieties under Cr-induced stress conditions as compared to the control group. Foliar application of trehalose at a concentration of 30 mM was administered to both maize varieties, leading to a noteworthy reduction in the detrimental effects of Cr stress. Notably, the Cr (0.5 mM) stress more adversely affected the shoot length more than 0.3mM of Cr stress. Cr stress (0.5 mM) significantly reduced the shoot length by 12.4% in FH-1046 and 24.5% in FH-1453 while Trehalose increased shoot length by 30.19% and 4.75% in FH-1046 and FH-1453 respectively. Cr stress significantly constrained growth and biochemical processes, whereas trehalose notably improved plant growth by reducing Cr uptake and minimizing oxidative stress caused by Cr. This reduction in oxidative stress was evidenced by decreased production of proline, SOD, POD, MDA, H2O2, catalase, and APX. Trehalose also enhanced photosynthetic activities under Cr stress, as indicated by increased values of chlorophyll a, b, and carotenoids. Furthermore, the ameliorative potential of trehalose was demonstrated by increased contents of proteins and carbohydrates and a decrease in Cr uptake.RESULTSTwo maize varieties, FH-1046 and FH-1453, were subjected to two different Cr concentrations (0.3 mM, and 0.5 mM). The results revealed significant variations in growth and biochemical parameters for both maize varieties under Cr-induced stress conditions as compared to the control group. Foliar application of trehalose at a concentration of 30 mM was administered to both maize varieties, leading to a noteworthy reduction in the detrimental effects of Cr stress. Notably, the Cr (0.5 mM) stress more adversely affected the shoot length more than 0.3mM of Cr stress. Cr stress (0.5 mM) significantly reduced the shoot length by 12.4% in FH-1046 and 24.5% in FH-1453 while Trehalose increased shoot length by 30.19% and 4.75% in FH-1046 and FH-1453 respectively. Cr stress significantly constrained growth and biochemical processes, whereas trehalose notably improved plant growth by reducing Cr uptake and minimizing oxidative stress caused by Cr. This reduction in oxidative stress was evidenced by decreased production of proline, SOD, POD, MDA, H2O2, catalase, and APX. Trehalose also enhanced photosynthetic activities under Cr stress, as indicated by increased values of chlorophyll a, b, and carotenoids. Furthermore, the ameliorative potential of trehalose was demonstrated by increased contents of proteins and carbohydrates and a decrease in Cr uptake.The study demonstrates that trehalose application substantially improved growth and enhanced photosynthetic activities in both maize varieties. Trehalose (30 mM) significantly increased the plant biomass, reduced ROS production and enhanced resilience to Cr stress even at 0.5 mM.CONCLUSIONSThe study demonstrates that trehalose application substantially improved growth and enhanced photosynthetic activities in both maize varieties. Trehalose (30 mM) significantly increased the plant biomass, reduced ROS production and enhanced resilience to Cr stress even at 0.5 mM.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing ...countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants, however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (
L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after 1 week, whereas, water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L
resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%), and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fiber (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se foliar spray (40 mg L
) is a handy, feasible and cost-effective approach to improve maize fodder yield and quality in arid and semi-arid regions of the world facing acute shortage of water.
Maize is a sensitive crop to drought and heat stresses, particularly at the reproductive stages of development. The present study investigated the individual and interactive effects of drought (50% ...field capacity) and heat (38 °C/30 °C) stresses on morpho-physiological growth, yield, nutrient uptake and oxidative metabolism in two maize hybrids i.e., 'Xida 889' and 'Xida 319'. The stress treatments were applied at tasseling stage for 15 days. Drought, heat and drought + heat stress caused oxidative stress by the over-production of ROS (O
, H
O
, OH
) and enhanced malondialdehyde contents, which led to reduced photosynthetic components, nutrients uptake and yield attributes. The concurrent occurrence of drought and heat was more severe for maize growth than the single stress. However, both stresses induced the metabolites accumulation and enzymatic and non-enzymatic antioxidants to prevent the oxidative damage. The performance of Xida 899 was more prominent than the Xida 319. The greater tolerance of Xida 889 to heat and drought stresses was attributed to strong antioxidant defense system, higher osmolyte accumulation, and maintenance of photosynthetic pigments and nutrient balance compared with Xida 319.
In the environment co-contamination of several toxicants commonly occurs. However, toxicological studies usually are focused on only one toxicant. The aim of this study was to investigate toxicity of ...silver nanoparticles (AgNP) and mycotoxin fumonisin B1 (FB1) and their possible interactions as well as to explore tentative mechanism of their toxic effect. Duckweed (Lemna minor L.) was treated with AgNP or FB1 (at concentrations 0.5 and 1.0 mg L−1) or with their combination at same concentrations for 3 days. Both AgNP and FB1, applied individually significantly affected levels of certain nutrients, reduced growth rate and the levels of photosynthetic pigments though AgNP at a much greater extent compared to FB1. Furthermore, AgNP induced ROS generation, lipid peroxidation and increase of antioxidative enzymes activities, while FB1 induced changes only in the activities of antioxidative enzymes. Those results implicate that phytotoxicity of both AgNP and FB1 can be associated with imbalance of mineral and cell redox status. However, toxic actions of AgNp singly applied were more pronounced. Combined treatment with AgNP and FB1 produced higher degree of changes in all parameters than corresponding concentrations of AgNP or FB1 alone implying their additive effects. Additionally, higher level of FB1 found in medium, and higher level of intracellular Ag following combined treatment indicates interaction of two toxicants at the transport level/uptake in the cell which resulted in higher accumulation of Ag in duckweed cells. The latter in turn exerted higher toxicity to duckweed compared to single treatment of AgNP.
•Phytotoxicity of nanosilver (AgNP) and fumonisin B1 (FB1) was assessed.•Both contaminants caused growth inhibition and oxidative stress.•Higher toxicity of AgNP is linked with intracellular accumulation of Ag.•Additive effects are observed when AgNP and FB1 are applied together.
The effect of drought stress on the production of secondary metabolites and photosynthetic pigments in safflower, Carthamus tinctorius L., was studied in the present work. The application of two ...regulating signaling molecules of salicylic acid (SA) and sodium nitroprusside (SNP) were respectively examined at concentrations of 250 μM and 25 μM on the plants subjected to different field capacity (FC) volumes of water (25% and 100%). The drought stress decreased the leaf number and area, shoot fresh and dry weights, and shoot length, whereas the root length and fresh weight were increased. There was an increase in the secondary metabolites (flavonoids, anthocyanin, phenol, and phenylalanine ammonia lyase activity) and a decrease in photosynthetic pigments. The SA treatment improved the rate of photosynthesis, anthocyanin content, and phenylalanine ammonia lyase activity. The SNP treatment improved the growth of aerial parts and hindered the root elongation possibly because of their free radical scavenging ability. The drought stress can be applied for enhanced production of secondary metabolites and the simultaneous administration of SA and SNP can be proposed as a mitigation strategy to reserve the normal plant function.
Salinity decreases yield in arid and semi-arid areas. With increasing demand for irrigation water, alternative sources are being sought. Seawater salinity was previously considered unusable for ...irrigation. However, this water can be used successfully to grow crops under certain conditions. Amino acids is well known biostimulant which has positive effects on plant growth and yield, and significantly mitigates the injuries caused by abiotic stresses. Therefore, in the present study, the effect of exogenously treatment amino acid on faba bean plant growing under seawater salt stress was investigated. Reduction of salinity damage in faba bean by using a mixture of amino acids to improve morphological and biochemical parameters, and thus raising the level of plant yield was tested. A pot experiment was conducted to alleviate the harmful effects of seawater salinity on faba bean cv. Giza 843 by foliar spraying of an amino acid mixture with different concentrations (0.0, 500, 1000 or 1500 mg L-1). Irrigation of faba bean plants with seawater levels of 3.13 and 6.25 dS m-1 led to significant reductions in shoot length, number of leaves per plant, fresh and dry weight of shoots, photosynthetic pigments, total carbohydrates, polysaccharides, nucleic acid DNA and RNA contents of faba bean leaves. Seawater salinity induced higher contents of Na+ and Cl- and decreased contents of K+, K+:Na+, Ca2+, Mg2+ and P3+. Irrigation of faba bean plant with different levels of seawater decreased seed yield and total dry weight per plant compared with those irrigated with tap water. Also, total carbohydrates and total protein contents in seeds were reduced by increased seawater salinity levels. Amino acid application as foliar spray significantly improved all the reduced parameters due to seawater stress. However, the highest level of amino acid of 1500 mg L-1 exerted the strongest effect in alleviating the harmful effect of seawater salinity stress.
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Rapid industrialization and population growth have increased the world's energy demands, resulting in a shortage of conventional fossil fuels. Thus, there is an urgent need to develop ...sustainable and renewable forms of energy. Microalgae have emerged as a potential feedstock for biofuel production. Under stress conditions, lipid production is enhanced in algal cells due to changes in the lipid biosynthetic pathways that produce neutral lipids. In this study, we examined the physiological and biochemical effects of salinity stress (0.00, 0.01, 0.10, 0.15, 0.20M) on the freshwater microalga Scenedesmus obliquus XJ002. We found that the biomass and the content of chlorophyll a, b and carotenoids decreased with increasing NaCl concentration. NaCl stress damaged the oxygen evolving complex (OEC) and the PSII (photosystem II) reaction center and subsequently suppressed electron transport at the donor and receptor sides of the reaction center, influencing the absorption, transfer, and application of light energy. Additionally, the total lipid content of cells was significantly increased under NaCl stress treatment. The highest lipid content (32.26%) was found in cells cultured in the presence of 0.20M NaCl, which was about 2.52-fold higher than that of cells grown in medium lacking NaCl (12.82%). In addition to providing insight into the physiological and biochemical responses of S. obliquus XJ002 to salinity stress, these findings show that lipid production, and hence biofuel feedstock production, can be boosted by adjusting salt levels in the growth medium.
•Salt stress on photosynthesis, accumulation of metabolites in Scenedesmus obliquus was investigated.•NaCl stress damages the oxygen evolving complex and the PSII reaction center.•NaCl stress suppresses electron transport at the donor and receptor side of the reaction center.•The neutral lipid content of cells was significantly increased under salt stress treatment.
Salinity is one of the major abiotic stresses which affects plant cell metabolism and reduces plant productivity. Variations in the antioxidant defence systems under salinity among two bean genotypes ...were investigated. Our results indicate that the difference between the genotypes in response to salinity is a quantitative trait rather than qualitative since they develop the same strategies with a significant variation in the rate of synthesis and accumulation, with the exemption of the antioxidant defence based on the synthesis of phenolic compounds. For both genotypes, salinity induced a marked reduction in dry matter gain in roots and shoots along with oxidative stress as indicated by the significant increase in malondialdehyde content. In addition, the photosynthetic pigments decreased with the increase of salinity. The only qualitative difference that we found among both genotypes was the decrease of total production of phenolic compounds in leaves that was only detectable in the low-yielding genotype under high salinity. The high-yielding genotype may have a better protection against oxidative damages by increasing the activity of antioxidant enzymes and the amounts of total flavonoids and ascorbic acid under high salinity, which allows maintaining higher yield even upon stress conditions. These results indicate that salt induced oxidative stress in bean is mainly counteracted by enzymatic defence systems, and that the metabolism of phenolic compounds is induced under very extreme conditions. The selection of genotypes for this trait will increase yield under stress conditions.
•Antioxidant defence systems between two bean genotypes are analysed under salinity.•Differences are quantitative rather than qualitative except for phenolic metabolism.•Oxidative stress in bean is counteracted mainly by the enzymatic defence system.•Phenolic compounds decrease in the low-yielding genotype under high salinity.•Phenolic compounds are induced in high-yielding genotype under extreme conditions.
Presence of nanoplastics within aqueous media has raised concerns about their adverse impacts on aquatic organisms. This study evaluated toxic effects of amino-functionalized polystyrene nanoplastics ...(PS–NH2) with diameters of 90 (PS–NH2-90), 200 (PS–NH2-200) and 300 (PS–NH2-300) nm on green microalgae Chlorella vulgaris. A dose-dependent toxicity response by PS-NH2-90 and/or PS-NH2-200 on biomass and photosynthetic pigment (chlorophyll a) end-points of C. vulgaris was observed. Whereas varied concentrations of PS-NH2-300 had no significant toxic effect on biomass and chlorophyll a end-points compared to control groups (p > 0.05). A comparison of toxicity of similar concentrations of PS-NH2-90, PS-NH2-200 and PS-NH2-300 showed small-sized PS-NH2 were more toxic than large-sized PS-NH2 (toxicity of PS-NH2 increased in the order PS-NH2-300 < PS-NH2-200 < PS-NH2-90). With decreasing PS-NH2 size, greater morphological changes and loss of original shape were observed, so that algal density/size reduced, and cell aggregations increased. Since PS-NH2 have high affinity to C. vulgaris due to electrostatic interaction with polysaccharide wall of algae, this could be as the main reason for formation of large aggregates at high concentrations of PS-NH2 compared to low concentrations of PS-NH2 used in algae medium. At high concentrations, PS-NH2 may act as intermediaries for connection of algal cells and therefore formation of aggregates. Field emission scanning electron microscopy images confirmed that high amounts of PS-NH2-90 were found to be embedded and adsorbed on algal cells, thereby limiting transfer of materials, gas exchange and energy between the aqueous medium and algal cells. These data may have serious ecological health implications, as C. vulgaris are important primary producers responsible for producing oxygen in aquatic environments.
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•Dose-dependent toxicity of PS-NH2 nanoplastics with 90, 200 and 300 nm diameters were evaluated on Chlorella vulgaris.•Small-sized PS-NH2 were more toxic than large-sized PS-NH2 to C. vulgaris.•With decreasing PS-NH2 size, greater morphological changes were observed.•PS-NH2-90 nanoplastics embedded and sorbed onto algal cells.•PS-NH2-300 nanoplastics had no toxic effect on C. vulgaris biomass and chlorophyll a.
Drought stress (DS) is a major concern in the agricultural sector and, in particular, for sugar beet production and sugar content. As such several agricultural practices have been used to minimize ...yield losses from DS, and foliar application of proline is considered one such approach to improve drought tolerance in growing plants. Hence, the current study examined the proline-related improvements to induce drought tolerance in sugar beet plants. A field experiment was conducted at two locations (Shahrekord and Shalamzar) in Chaharmahal-Bakhtiari province, Iran. Experimental treatments comprised of three DS levels (well water: 100%; mild stress: 75%; severe stress: 50% water requirement of plant), and three proline applications (control: 0; low: 5 mM; high: 10 mM). DS caused a significant up-regulation in leaf proline content, malondialdehyde (MDA) content, hydrogen peroxide (H
2
O
2
) content, ascorbate peroxidase, catalase, and peroxidase enzymatic activities. This increase was more pronounced under proline application with concomitant down-regulation of MDA and H
2
O
2
contents. DS also caused a decrease in leaf photosynthetic pigments, leaf relative water contents, membrane stability index and sugar beet root production; however, proline application mitigated these adverse DS effects. The study results suggest beneficial effects of proline applications, which is crucial to mitigation of the detrimental effects of DS in sugar beet by enhancing antioxidant enzymatic activities with concomitant reduction in MDA and H
2
O
2
contents.
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