Increase In Pigment Content Research Articles

Do Lignin Nanoparticles Pave the Way for a Sustainable Nanocircular Economy? Biostimulant Effect of Nanoscaled Lignin in Tomato Plants.

Agriculture has a significant environmental impact and is simultaneously called to major challenges, such as responding to the need to develop more sustainable cropping systems with higher productivity. In this context, the present study aimed to obtain lignin nanoparticles (LNs) from pomace, a waste product of the olive oil chain, to be used as a nanobiostimulant in tomato plants. The biostimulant effect of this biopolymer is known, but its reduction to nanometer size can emphasize this property. Tomato plants were subjected to different LN dosages (25, 50, and 100 mg L-1) by foliar application, and inductive effects on photosynthetic machinery, aerial and root biomass production, and root morphology were observed. The treated plants showed increased efficiency in catching and using light, while they reduced the fraction dissipated as heat or potentially toxic to cells for the possibility of creating reactive oxygen species (ROS). Finally, this benefit was matched by increased pigment content and a stimulatory action on the content of nitrogen (NBI) and antioxidant substances such as flavonoids. In conclusion, the present study broadens the horizon of substances with biostimulant action by demonstrating the validity and efficacy of nanobiostimulants obtained from biological residues from the olive oil production chain.

Biodegradable thermochromic polylactic acid (PLA) sensor

Abstract This study investigates the development of polylactic acid (PLA) by incorporating thermochromic black pigments (TCB) at varying concentrations of 0, 0.5, 1, 2 and 3 wt% through the process of melt blending. The color transition and reversion behaviors of the resulting specimens were examined at different temperatures (−10, 10, 30, 35 and 50 °C) using colorimetric analysis. Additionally, mechanical properties, thermal characteristic and thermal stability were assessed through tensile testing, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. The study revealed that an increase in TCB concentrations led to a reduction in lightness (L*). Higher pigment content enhanced thermochromic properties, resulting in more pronounced color changes. The total color difference (ΔE) remained reproducible over five cycles of heating and freezing, and this reproducibility persisted after thermal aging. Tensile strength and elongation at break exhibited improvement with increasing pigment content. Glass transition temperature (Tg) and melting temperature (Tm) of the thermochromic samples showed minimal reduction compared to that of neat PLA, which is 64.2 °C. Crystallinity degree (Xc) increased slightly by 0.2–0.92 %. The thermal stability of the PLA matrix was only marginally affected by the presence of thermochromic pigments.

Properties of Gelatin-based Films Incorporated with Anthocyanins and Curcuminoids and Stability of Antioxidant Activity during In Vitro Digestion

In this study, gelatin-based films incorporated with two plant pigments; butterfly pea flower anthocyanins (BPA) and turmeric rhizome curcuminoids (TRC) were prepared. Their physical and antioxidant properties were investigated. The results showed that addition of BPA and TRC at different concentrations (10%, 20%, and 30% of gelatin weight) significantly affected the visible color and color values (L*, a*, b*, hue and chroma) of the obtained films. With increasing pigment concentrations, lower % light transmittance was observed (p<0.05). The improved light barrier property corresponded with the increased opacity of the two films (p<0.05). Compared with the control films, the addition of either BPA or TRC slightly increased thickness of films (p<0.05). The moisture content of films increased with increasing BPA concentration but decreased with increasing TRC concentration (p<0.05). However, water solubility was not significantly different among films with varying concentrations of BPA or TRC (p>0.05). Total anthocyanin content (TAC), total curcuminoid content (TCC), total phenol content, and antioxidant activities by FRAP and DPPH increased with increasing pigment concentration in films (p<0.05). Based on in vitro digestion, the film forming solution containing 30% (w/w) plant pigment significantly improved the stability of pigment compounds, TPC, and antioxidant activities during the intestinal phase. Compared to the pigment extract alone, film forming solution containing gelatin and glycerol showed protecting effects against biological conditions during intestinal digestion of the two pigments, BPA and TRC, and therefore, offered greater stability of antioxidant activity (p<0.05).

Rootstock mediated alteration in morphology and photosystem in sweet orange (Citrus sinensis) scion cv. Pusa Sharad under NaCl stress

There is a dearth of rootstock studies on how salinity stress imparts tolerance to the scion cultivar in citrus [Citrus sinensis (L.) Osbeck]. The impact of sodium chloride on sweet orange cv. Pusa Sharad (PS) grafted on 11 different rootstocks i.e. Jatti khatti (JK), X–639 (X9), CRH–12 (C12), NRCC–1 (N1), NRCC–2 (N2), NRCC–3 (N3), NRCC–4 (N4), NRCC–5 (N5), Troyer citrange (TC), CRH–47 (C47) and Cleopatra mandarin (CM) was evaluated at the nursery unit of ICAR-Indian Agricultural Research Institute, New Delhi, during 2019–22. Irrigation water containing 30 and 60 mM of sodium chloride (NaCl) was applied to scion/rootstock combinations in comparison to control (without NaCl) till the onset of salt injury symptoms i.e. 42 days. Under salinity stress, the PS scion grafted onto CM, X9, C47, N1, and N3 rootstocks exhibited minimum reduction in the scion height, leaf area ratio, root to shoot ratio, total chlorophyll content, total carotenoid content, transpiration rate, photosynthesis rate, internal CO2 concentration and stomatal conductance as compared to PS scions grafted onto JK, C12, N2, N4, N5, and TC rootstocks under 60 mM NaCl stress. Results showed that specific rootstock can enhance salt-tolerance potential by increasing pigment content and strengthening the photosystem. PS scions grafted onto CM, C47, X9, N1, and N3 demonstrated greater NaCl tolerance compared to those grafted onto JK, C12, N2, N4, N5, and TC and hence recommended for areas having salinity level up to 60 mM.

The seaweed Ascophyllum nodosum-based biostimulant enhances salt stress tolerance in rice (Oryza sativa L.) by remodeling physiological, biochemical, and metabolic responses

ABSTRACT This study explores the role of a biostimulant derived from the seaweed Ascophyllum nodosum (AN) in mitigating salt stress in rice plants. The weekly (S+W) and biweekly (S+B) biostimulant treatments exhibited enhanced shoot and root biomass, maintained ionic balance, and increased pigment content (total chlorophyll increased by 26.35% and 31%, carotenoids by 11.90% and 16.67% in S+W and S+B treatments, respectively) compared to untreated salt-stressed plants (CS). Improved gas exchange parameters and PSII efficiency were observed in S+W and S+B treatments. AN-biostimulant treatments mitigated salt-induced oxidative stress by positively regulating the antioxidant defense system. Notably, a strong negative correlation was observed between antioxidants and oxidative markers. Furthermore, AN-biostimulant treatments induced key metabolites (organic acids, sugars, amino acids, flavonoids), emphasizing the integrated role of multiple pathways in enhancing salt tolerance in rice. These findings highlight the potential of AN biostimulants as eco-friendly tools for crop enhancement in challenging environments.

Elicitation with hydrogen peroxide promotes growth, phenolic-enrichment, antioxidant activity and nutritional values of two hydroponic lettuce genotypes.

Dietary vegetables rich in bioactive compounds are major responsible for promoting human health. Herein, the effect of hydrogen peroxide (H2O2), an important signaling compound, on growth and quality of two hydroponic lettuce genotypes was investigated. The maximum enhancement of growth traits was shown in lettuce elicited with 10mmol/L H2O2, while 40mmol/L H2O2 significantly reduced above growth traits. H2O2 elicitation increased pigment contents and photosynthetic process, which consequently caused enhancements of phenolic compounds, ascorbic acid, glutathione, carotenoids, soluble sugars, free amino acids, soluble protein, minerals, and antioxidant capacity, while above alterations appeared in a genotype-dependent manner. The phenolic accumulation was correlated with improved activity of phenylalanine ammonia lyase (PAL) and expression levels of genes related to phenolic biosynthesis, including PAL, chalcone synthase, flavanone 3-hydroxylase, dihydroflavonol-4 reductase, and UDP-glucose: flavonoid 3-O-glucosyltransferase. Therefore, elicitation with H2O2 is a promising strategy to develop lettuce with high bioactive compounds and biomass.

Starch-Based Superabsorbent Enhances the Growth and Physiological Traits of Ornamental Shrubs

Periods of heat and water deficit often occur together and are especially dangerous for plants grown in pots, where the substrate volume for roots is limited. The purpose of the present research was to understand the response of shrubs planted in containers to the addition of a starch-based superabsorbent to their growing medium. The growth parameters, physiological conditions, and oxidative stress of Cornus alba ’Aurea’, Hydrangea paniculata ‘Limelight’, and Physocarpus opulifolius ‘Red Baron’ were assessed by adding a hydrogel (1, 2, or 3 g·dm−3) to their growing medium. The use of the superabsorbent improved the stomatal conductance and photosynthetic rate, resulting in better growth parameters. The application of 1 g·dm−3 hydrogel increased the chlorophyll content in hydrangea and ninebark leaves (8%) and increased the content of total soluble sugars in these plants (12% and 15%, respectively). The highest increase in reducing sugars was caused by a dosage of 3 g·dm−3. The lowest dose of hydrogel resulted in a decrease in hydrogen peroxide content in the leaves of all the taxa. The relationship between the contents of biologically active components and oxidative stress proved ambiguous for all the taxa. Oxidative stress was reduced, as evidenced by lower hydrogen peroxide and an increase in pigment content. In summary, a hydrogel dosage of 2 g·dm−3 in the medium could be optimal in pot nursery production using 3 dm3 pots.

Alleviation of NaCl stress in tomato varieties by promoting morpho-physiological attributes and biochemical characters

Salinity is a significant abiotic stress, affecting plant growth and productivity during all plant developmental stages. Soil salinization due to climate change is increasing crop loss every year. Salinity is considered the most important abiotic stress limiting crop production and plants are known to be able to continue to survive under this stress by involving many mechanisms. Vegetable crops face huge yield losses due to abiotic stress. Salt stress creates physiological drought in plants affecting morphology and alters physiological functions that harm plants through various processes. Tomato is an essential annual crop providing human food worldwide. It is estimated that by the year 2050 > 50% of the arable land will become saline and, in this respect, in recent years, researchers have focused their attention on studying how tomato plants behave under various saline conditions. This study was conducted to observe the effects of NaCl salinity on four tomato (Lycopersicum esculentum L.) varieties in a pot experiment. Morphological and physio-biochemical properties of four tomato varieties (Rio Grande, Nadir, Bonita, and 19299) were exposed to NaCl-salinity (0, 100, 200, and 300 mM) through irrigation. All the varieties have differential responses to different levels of salt. Salinity stress reduced growth parameters in all varieties as compared to control plants. Plant Variety 4 (19299) showed significantly increased growth (root length, shoot length, number of roots, number of leaves, leaf area, plant fresh and dry weight) and physiological attributes (photosynthetic pigments, total soluble sugars, and total proteins) as compared to other varieties. Variety 4 (19299) has better protection against salt stress by increasing pigment content and enzymatic activity under salt stress. Antioxidants (peroxidase, catalase, and superoxide dismutase) were increased to maximum in variety 3 (Bonita) which is the most susceptible variety among all other varieties. Malondialdehyde (MDA) content, lycopene, anthocyanin, and H2O2 also increased in Variety 3 as compared to other varieties and control plants. Bonita variety showed maximum reduction in root length, shoot length, number of roots, fresh and dry matter content as well as in leaf area while comparing with other three varieties. The study revealed that the 19299 variety is salt tolerant, Rio Grande and Nadir are intermediates while the Bonita variety is susceptible to salt stress.

Controlling root zone temperature improves plant growth and pigments in hydroponic lettuce.

Air and root zone temperatures are important environmental factors affecting plant growth and yield. Numerous studies have demonstrated that air temperature strongly affects plant growth and development. Despite the extensive literature on air temperature, comprehensive studies on the effects of root zone temperature (RZT) on plant growth, elemental composition, and pigments are limited. In this study, we carefully observed the effects of RZT in red leaf lettuce to understand its effect on lettuce growth and pigment content. Lettuce (Lactuca sativa, red leaf cultivar 'Red Fire') was grown hydroponically in a plant factory with artificial light under three RZT treatments (15, 25, or 35 °C) for 13 days. We investigated the comprehensive effects of RZT on the production of red leaf lettuce by metabolome and ionome analyses. The 25 °C RZT treatment achieved maximum shoot and root dry weight. The 35 °C RZT decreased plant growth but significantly increased pigment contents (e.g. anthocyanins, carotenoids). In addition, a RZT heating treatment during plant cultivation that changed from 25 to 35 °C RZT for 8 days before harvest significantly increased shoot dry weight compared with the 35 °C RZT and significantly increased pigments compared with the 25 °C RZT. The 15 °C RZT resulted in significantly less pigment content relative to the 35 °C RZT. The 15 °C RZT also resulted in shoot and root dry weights greater than the 35 °C RZT but less than the 25 °C RZT. This study demonstrated that plant growth and pigments can be enhanced by adjusting RZT during different stages of plant growth to attain enhanced pigment contents while minimizing yield loss. This suggests that controlling RZT could be a viable method to improve lettuce quality via enhancement of pigment content quality while maintaining acceptable yields.

UV-Spectroscopic Studies on the Potential State of Spirulina Cultures using Varied Culture Media in Uncontrolled Laboratory Conditions in Ballari Region

Spirulina platensis is a filamentous cyanobacteria obtained from the wild was subject to exposure to different concentrations of media namely Zarrouk’s and BG-11. The hydrological parameters were maintained naturally in the arid regions of Ballari district. The increased temperature during summer months and dry air substantially had a negative effect on the quality of the filamentous algae. The UV Spectroscopy absorbance showed increased levels with increase in pigment concentration. The study revealed that highest absorbance patterns are due to greater number of chromophores found in the order of the samples A2>A>S2> S1 respectively.

Comparative transcriptome analysis reveals an insight into the candidate genes involved in anthocyanin and scent volatiles biosynthesis in colour changing flowers of Combretum indicum.

Combretum indicum is a widely cultivated ornamental species displaying the distinct phenomenon of floral colour change. Flowers display a gradual colour change from white to red, attributed to increased cyanidin 3-O glucoside in petal tissues. The differently coloured flowers also emanate a complex blend of VOCs with trans-linalool oxide (furanoid) as the major compound in the emission profile. To understand molecular mechanisms regulating floral colour shifts and scent biosynthesis, we performed Illumina transcriptome sequencing, including de novo assembly and functional annotation, for the two stages of floral maturation (white and red). Homology analysis with functional classification identified 84 and 42 candidate genes associated with pigment and scent biosynthesis, respectively. Genes encoding transcription factors, such as MYB, ERF, WD40, WRKY, NAC, bHLH and bZIP, that play critical roles in regulating specialized metabolism were also identified in the transcriptome data. Differences in expression of genes were consistent with accumulation patterns of anthocyanins in the two different flower colours. A clear upregulation of flavonoid biosynthesis genes in red flower tissue is associated with increased pigment content. RT-qPCR-based expression analyses gave results consistent with the RNA-Seq data, suggesting the sequencing data are consistent and reliable. This study presents the first report of genetic information for C. indicum. Gene sequences generated from RNA-Seq, along with candidate genes identified by pathway mapping and their expression profiles, provide a valuable resource for subsequent studies towards molecular understanding of specialized metabolism in C. indicum flowers.

Physiological responses and adjustments of corals to strong seasonal temperature variations (20-28°C).

Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their counterparts in the tropics. This study investigated the effect of temperature reductions on Montastraea cavernosa and Porites astreoides in Bermuda (32°N; sea surface temperature ∼19-29°C) over 5 weeks, applying the following treatments: (i) constant control temperature at 28°C, and (ii) temperature reduction (0.5°Cday-1) followed by constant temperature (20 days; acclimatization period) at 24°C and (iii) at 20°C. Both species decreased photosynthesis and respiration during temperature reduction as expected, which continued to decrease during the acclimatization period, indicating adjustment to a low energy turnover rather than thermal compensation. Trajectories of physiological adjustments and level of thermal compensation, however, differed between species. Montastraea cavernosa zooxanthellae metrics showed a strong initial response to temperature reduction, followed by a return to close to control values during the acclimatization period, reflecting a high physiological flexibility and low thermal compensation. Porites astreoides zooxanthellae, in contrast, showed no initial response, but an increase in pigment concentration per zooxanthellae and similar photosynthesis rates at 24°C and 20°C at the end of the experiment, indicating low acute thermal sensitivity and the ability for thermal compensation at the lowest temperature. Respiration decreased more strongly than photosynthesis, leading to significant build-up of biomass in both species (energy reserves). Results are important in the light of potential poleward migration of corals and of potential latitudinal and species-specific differences in coral thermal tolerance.

Evaluation of the biostimulant effects of two Chlorophyta microalgae on tomato (Solanum lycopersicum)

Eukaryotic microalgae from the Chlorophyta division are used in various bio-industries due to their ability to produce high value compounds. Some of these compounds show plant biostimulant properties when applied to plants, soil or growth medium in hydroponic chambers. The first objective of this study was to evaluate if Chlamydomonas reinhardtii cc 124 and Chlorella sp. MACC-360 had biostimulant effect on Solanum lycopersicum L. The second objective was to investigate the importance of the application mode and time. The third goal was to reveal strain-specific actions of the two algae strains. Tomato plants were grown in pots layered with clay at the bottom and filled with the mixture of soil and vermiculate. In two sets of experiments the soil and plant leaves were treated with living algae and algal extract, respectively. In the first set, the culture suspension (CS) was centrifuged, the algae pellet was re-suspended in water (CCS), and this was applied weekly to soil, while algae extract (cell disrupted algae suspension – CDS) was sprayed on leaves bi-weekly. The flowering process, plant morphology, fruit features and pigment contents were analyzed. In the second set of experiments, the culture suspension per se (CS) was applied to the soil weekly and CDS was sprayed on leaves bi-weekly. Flowering kinetics, reproductive capacity and photosynthetic parameters were examined. Both algae strains increased pigment content, fruit weight and fruit diameter of tomato. Plants that received initial algae treatment at an advanced age performed better than those initially treated at a young age. Chlorella induced early flowering and fruit development while Chlamydomonas significantly delayed these milestone functions. Chlorella promoted conversion of light energy to chemical energy, while Chlamydomonas enhanced protection of photosynthetic parameters. Both strains increased leaf temperature differential as well as leaf thickness. Overall, both algae strains stimulated important agronomic-valuable functions in tomato.

Early evidence of the impacts of microplastic and nanoplastic pollution on the growth and physiology of the seagrass Cymodocea nodosa

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous in natural habitats and the risks their presence poses to marine environments and organisms are of increasing concern. There is evidence that seagrass meadows are particularly prone to accumulate plastic debris, including polystyrene particles, but the impacts of this pollutant on seagrass performance are currently unknown. This is a relevant knowledge gap as seagrasses provide multiple ecosystem services and are declining globally due to anthropogenic impact and climate-change-related stressors.Here, we explored the potential effects of a 12 day-exposure of seagrasses to one concentration (68 μg/L) of polystyrene MPs and NPs on the growth, oxidative status, and photosynthetic efficiency of plants using the foundation species Cymodocea nodosa as a model. Among plant organs, adventitious roots were particularly affected by MPs and NPs showing complete degeneration. The number of leaves per shoot was lower in MPs- and NPs-treated plants compared to control plants, and leaf loss exceeded new leaf production in MPs-treated plants. MPs also reduced photochemical efficiency and increased pigment content compared to control plants. Shoots of NPs-treated plants showed a greater oxidative damage and phenol content than those of control plants and MPs-treated plants. Biochemical data about oxidative stress markers were consistent with histochemical results. The effects of MPs on C. nodosa could be related to their adhesion to plant surface while those of NPs to entering tissues.Our study provides the first experimental evidence of the potential harmful effects of MPs/NPs on seagrass development. It also suggests that the exposure of seagrasses to MPs/NPs in natural environments could have negative consequences on the functioning of seagrass ecosystems. This stresses the importance of implementing cleaning programs to remove all plastics already present in marine habitats as well as of undertaking specific actions to prevent the introduction of these pollutants within seagrass meadows.

VDAC1 negatively regulates melanogenesis through the Ca2+-calcineurin-CRTC1-MITF pathway.

Melanocytes produce melanin for protecting DNA from ultraviolet exposure to maintain genomic stability. However, the precise regulation of melanogenesis is not fully understood. VDAC1, which is mainly localized in the outer mitochondrial membrane, functions as a gatekeeper for the entry or exit of Ca2+ between mitochondria and the cytosol and participates in multiple physiological processes. Here, we showed a novel role of VDAC1 in melanogenesis. Depletion of VDAC1 increased pigment content and up-regulated melanogenic genes, TYR, TYRP1, and TYRP2 Knockdown of VDAC1 increased free cytosolic Ca2+ in cultured melanocytes at the resting state, which activated calcineurin through the Ca2+-calmodulin-CaN pathway. The activated CaN dephosphorylated CRTC1 to facilitate its nuclear translocation and ultimately up-regulated the transcription of the master regulator of melanogenesis MITF. Consistently, depletion of Vdac1 in mice led to up-regulation of the transcription of MITF and thereafter its targeted melanogenic genes. These findings suggest that VDAC1 is an important negative regulator of melanogenesis, which expands our knowledge about pigment production and implies its potential role in melanoma.

Effects of different light-emitting diode qualities on the growth and photosynthetic characteristics of Spathiphyllum floribundum

Spathiphyllum floribundum (Linden & André) N.E.Br. is an important indoor flower species. Thus, optimizing its growth by regulating the light quality under indoor low-light conditions may be critical for generating high-quality flowers. In this study, the effects of the following six light-quality treatments on peroxidase and superoxide dismutase activities in two S. floribundum cultivars (“Sweet Chico” and “Queen”) were analyzed: monochromatic light comprising 100% red (R, 657 nm) or 100% blue (B, 450 nm) light, a combination of R and B lights [80% R + 20% B (8:2), 70% R + 30% B (7:3), and 60% R + 40% B (6:4)], and white light. The light treatments were performed using light-emitting diodes. The light intensity and photoperiod were set to 45 ± 2 µmol·m−2·s−1 and 14 h·day−1, respectively. The results of this study revealed that an appropriate R:B light ratio may lead to increased pigment contents, thereby increasing the synthesis and accumulation of photosynthetic products, which will result in increased stress resistance and enhanced growth. These findings provide the basis for future investigations on the growth and production of S. floribundum and other indoor ornamental plants.

Distinctive phenolic accumulation response to temperature-induced by row orientation of two field-grown Vitis vinifera cultivars

PurposePhenolic compounds play a critical role in grape quality, and their content is strongly influenced by bunch zone temperature during the ripening period. The mechanism of responding to temperature was found to highly depend on cultivars. The present study aimed to evaluate the effects of row orientation and canopy side on phenolic content in grape berries.Design/methodology/approachThe authors analyzed the accumulation of phenolic compounds in mature berries of Cabernet Sauvignon and Cabernet Gernischt. They were harvested from various canopy sides of north-south and east-west row orientations, which were NS–E and NS–W, EW–S and EW–N.FindingsDuring the ripening period, mean temperatures of the bunch zones, NS–W and EW–N were respectively higher than NS–E and EW–S. At harvest, the total phenolic, total anthocyanin, tannin and reducing sugar contents were higher in NS–E and EW–S, than in NS–W and EW–N, respectively, indicating a negative relationship with temperature. For both varieties, EW–S had the highest proportion of malvidins anthocyanins. Peonidins, delphinidins, and cyanidins anthocyanins of EW–N showed a higher ratio in Cabernet Sauvignon, while NS–E showed a higher ratio in Cabernet Gernischt.Originality/valueTo improve grape monomeric anthocyanin content, the results indicate that Cabernet Sauvignon of NS–W and Cabernet Gernischt of NS–E can be utilized for an effective strategy. Moreover, the optimal combination planting choices with cultivars would improve wine quality by increasing pigment concentrations linked to the color and antioxidant potential.

Label-free proteomics approach reveals candidate proteins in rice (Oryza sativa L.) important for ACC deaminase producing bacteria-mediated tolerance against salt stress.

The omics-based studies are important for identifying characteristic proteins in plants to elucidate the mechanism of ACC deaminase producing bacteria-mediated salt tolerance. This study evaluates the changes in the proteome of rice inoculated with ACC deaminase producing bacteria under salt-stress conditions. Salt stress resulted in a significant decrease in photosynthetic pigments, whereas inoculation of Methylobacterium oryzae CBMB20 had significantly increased pigment contents under normal and salt-stress conditions. A total of 76, 51 and 33 differentially abundant proteins (DAPs) were identified in non-inoculated salt-stressed plants, bacteria-inoculated plants under normal and salt stress conditions respectively. The abundances of proteins responsible for ethylene emission and programmed cell death were increased, and that of photosynthesis-related proteins were decreased in non-inoculated plants under salt stress. However, bacteria-inoculated plants had shown higher abundance of antioxidant proteins, RuBisCo and ribosomal proteins that are important for enhancing stress tolerance and improving plant physiological traits. Collectively, salt stress might affect plant physiological traits by impairing photosynthetic machinery and accelerating apoptosis leading to a decline in biomass. However, inoculation of plants with bacteria can assist in enhancing photosynthetic activity, antioxidant activities and ethylene regulation related proteins for attenuating salt-induced apoptosis and sustaining growth and development.

The Role of Plant Growth Promoting Rhizosphere Microbiome as Alternative Biofertilizer in Boosting Solanum melongena L. Adaptation to Salinity Stress.

Recent ecological perturbations are presumed to be minimized by the application of biofertilizers as a safe alternative to chemical fertilizers. The current study aims to use bioinoculum (I) as an alternative biofertilizer and to alleviate salinity stress in the cultivar Solanum melongena L. Baldi. The salinity drench was 200 mM NaCl (S), which was used with different treatments (0; I; S; S + I) in pots prefilled with clay and sand (1:2). Results showed that salinity stress inhibited both plant fresh and dry weights, water content, and photosynthetic pigments. The content of root spermine (Spm), spermidine (Spd), and puterscine (Put) decreased. However, addition of the bioinoculum to salt-treated plants increased pigment content (80.35, 39.25, and 82.44% for chl a, chl b, and carotenoids, respectively). Similarly, K+, K+/Na+, Ca2+, P, and N contents were significantly enhanced. Increases were recorded for Spm + Spd and Put in root and shoot (8.4-F, 1.6-F and 2.04-F, 2.13-F, respectively). RAPD PCR showed gene expression upregulation of photosystem II D2 protein, glutathione reductase, glutathione-S-transferase, protease I, and protease II. The current work recommends application of the selected bioinoculum as a green biofertilizer and biopesticide. Additionally, the studied eggplant cultivar can be regarded as a source of salt tolerance genes in agricultural fields.

Co-cultivation with blue mussels increases yield and biomass quality of kelp

Integrated multi-trophic aquaculture (IMTA) has to date largely centred on a fed species, often finfish or shrimps, alongside which extractive species, such as bivalves or seaweeds, have been placed. In comparison, IMTA systems excluding a fed component have received little research. Here we report a field study of an IMTA cultivation of the sugar kelp, Saccharina latissima, and the blue mussel, Mytilus edulis, on the Swedish west coast. Kelp were cultivated at two depths, 1-2 m and 3-4 m, either 10 m downstream of commercial scale blue mussel farms, or at control (monoculture) sites at least 500 m from the nearest farm. Significant enhancement of kelp yields in terms of both blade length and biomass was observed in IMTA treatments compared to monoculture, with a mean increase in length of 22% and biomass of 38%. Moreover, kelps co-cultivated with mussels displayed an epiphyte reduction of more than half compared to kelps grown in monoculture, with a 15% coverage in monoculture compared to 6% in co-culture. Significant increases in pigment content were also detected, with higher levels of chlorophyll a, fucoxanthin and phaeophytin in IMTA treatment kelps in comparison to monoculture. This study provides evidence for the potential of IMTA systems containing solely extractive species and presents factors beyond nutrient enrichment as drivers for enhanced growth in these systems.