Total Chlorophyll Content Research Articles

Management of soft rot in pakchoi (Brassica chinensis L.) using polyphenols from pineapple peel waste

Soft rot is one of the most susceptible soil-borne diseases of pakchoi (Brassica chinensis L.), severely hindering its industrial development. The research aimed to evaluate the application effect of polyphenols extracted from pineapple peel waste in improving the rhizosphere soil environment of pakchoi infected by soft rot and promoting plant health and growth. We found that using pineapple peel polyphenols (PPPs) at 4 mg/mL concentration (P1 treatment) significantly improved soil quality, reduced pakchoi disease incidence, and effectively promoted pakchoi growth. Compared with the control group (CK), the P1 treatment led to a marked 79.97 % reduction in diseased pakchoi leaves. Meanwhile, the rhizosphere soil structure showed reduced diseased genera and increased beneficial bacterial phyla, along with boosted soil enzyme activities. Furthermore, P1 treatment improved key growth parameters of pakchoi, including neck thickness (62.07 %), plant height (57.43 %), fresh weight (154.52 %), dry weight (121.88 %), maximum leaf length (47.28 %), width (30.98 %), and total chlorophyll content (50.11 %). The application of PPPs has shown significant effects in enhancing the ecological environment of the diseased soil and reducing the incidence of soft rot disease of pakchoi and has great potential in increasing the yield of pakchoi. This study offers an eco-friendly and sustainable approach for the valorization of PPPs and the management of soil-borne diseases, which holds profound implications for enhancing crop quality, soil health, and human well-being.

Unraveling growth-promoting potential of plant beneficial actinobacteria on tropical bryophytes

Bryophytes are non-vascular plants with dominant gametophyte stage that play vital ecological roles in natural ecosystems. Unfortunately, their populations are currently in decline due to habitat destruction and various anthropogenic activities. The conservation efforts for bryophytes are hampered by their slow growth rates. This study aims to investigate the potential of actinobacteria to promote the growth of bryophytes. In this study, three plant growth-promoting actinobacteria, Dermacoccus abyssi MT1.1T, Micromonospora chalcea CMU55-4 and Streptomyces thermocarboxydus S3 were cultured in International Streptomyces Project medium 2 (ISP2) broth to obtain culture filtrates containing bioactive compounds for enhancing the growth of two bryophyte species, Physcomotrium sphaericum (C. Ludw.) Fürnr and Sphagnum cuspidatulum C. Müll. Interestingly, the incorporation of actinobacterial culture filtrates into 1/16 Murashige and Skoog (MS) medium yielded superior growth performance of P. sphaericum (C. Ludw.) Fürnr and S. cuspidatulum C. Müll, as observed from the thallus height, fresh weight, total chlorophyll contents, and total carotenoid contents compared to control groups. In addition, the inoculation of M. chalcea CMU55-4 on S. cuspidatulum C. Müll grown in sterile peat moss demonstrated the highest values for thallus height, fresh weight, dry weight, total chlorophyll content, and total carotenoid content. All actinobacteria successfully colonized the moss seedlings without any observable negative impacts, indicating beneficial interactions between actinobacteria and bryophytes. This research sheds light on the potential of harnessing plant beneficial actinobacteria to enhance the growth of bryophytes for conservation purposes.

Unveiling the impact of organically activated biochar on physiological, biochemical, and yield attributes of maize under varied field moisture conditions.

Water deficiency in semiarid regions is a limiting factor that affects crop quality and yield. In Punjab, Pakistan, a 27% decline in maize yield was detected over the past two decades just because of water scarcity. Currently, no studies have reported the effects of organically activated biochar (AB) on crop productivity under natural field conditions. For this purpose, a field experiment in a split-split-plot design was conducted with three amendment levels (0, 2, and 4 tonnes ac-1), and three maize hybrids (DK-9108, DK-6321, and Sarhaab) under 100%, 70%, and 50% irrigation water (IW) of crop evapotranspiration (ETc). The AB significantly improved the soil's physical and chemical properties, and maximum improvement was recorded in 4 tonnes ac-1 AB amendment in organic matter (16.6%), total organic carbon (17%), phosphorus (11.43%), and available potassium (29.27%). The 4 tonnes ac-1AB amendment in soil had a significant impact on total chlorophyll content (0.3-1-fold in DK-6321), carotenoid content (3.9-4.4-fold in Sarhaab), and relative water content (30% and 21% in Sarhaab) under 50% irrigation water (IW) of ETc at V14th and R3 stages, respectively. Moreover, a significant decline in stress markers (proline content and sugar content) was detected at both growth stages in all maize hybrids in AB amended soil. The analysis of plant metabolites indicated increased intensities of phenolics, alkyl esters, and carbohydrates by 2.5-7%, 17-80%, and 40-43% in DK-6321 under 50% IW in 2-4 tonnes ac-1 AB amended soil, respectively. The highest improvement in growth and yield attributes among maize hybrids was detected in the order DK-6321¿DK-9108¿Sarhaab in 2-4 tonnes ac-1AB amended soil under 70% and 50% IW of ETc, respectively. Hence, this research might help to develop an effective soil amendment to restore degraded soils and improve maize growth under arid climatic conditions.

Aluminium bioavailability and toxicity disrupted chloroplast structure and inhibited inorganic carbon utilization and nutrient uptake in Vallisneria natans at acidic and alkaline pH

Vallisneria natans, as submerged aquatic plants, face significant threats from aluminium (Al) toxicity. While the effects of Al at low pH on terrestrial plants have been extensively studied, there is a lack of research on the impacts of both low and high pH on chloroplast ultrastructure and nutrient uptake in submerged plants. This research is important as it aims to fill this gap by exposing the leaves of Vallisneria natans to 100 μM Al at varying pH levels (4.5, 5.5, 7.5, and 9.5) for 48 hours. The results showed that inorganic carbon (CT), CO2, and HCO3 content increased at extreme pH levels (4.5 and 9.5), suggesting decreased inorganic carbon utilization under Al stress. Additionally, photosystem II efficiency and electron transport rate were significantly reduced at extreme pH levels, highlighting the sensitivity of V. natans to Al. Chlorophyll a and total chlorophyll content were significantly lower at pH 4.5 compared to pH 7.5. Chloroplast structural disruptions were evident at extreme pH levels coupled with Al exposure, whereas minimal injury was observed at pH 5.5 and 7.5. The study also noted vacuole enlargement, altered plasma membrane permeability, and hematoxylin staining, indicating Al accumulation in leaves. ICP analysis revealed increased Al content at extreme pH levels, underscoring heightened Al bioavailability and toxicity. Significant reductions in macro and micronutrient content (P, Mg, K, Fe, Zn, B, Mn) were observed, likely due to Al-induced root and cell damage and altered nutrient uptake. These findings emphasize the complex interplay between Al exposure, pH fluctuations, and their cascading effects on the physiology and elemental composition of Vallisneria natans, highlighting the need for further research and environmental management strategies.

Phytotoxic Activity of Sesquiterpene Lactones-Enriched Fractions from Cynara cardunculus L. Leaves on Pre-Emergent and Post-Emergent Weed Species and Putative Mode of Action

Sesquiterpene lactones (SLs) are compounds that are highly produced in Cynara cardunculus leaves, known for their phytotoxic activity. This study aims to assess SL-enriched fractions’ (cynaropicrin, aguerin B, and grosheimin) phytotoxic potentials and putative modes of action, compared to an initial extract, using two approaches: first, against a panel of nine weed species in pre-emergence, and then on Portulaca oleracea L.’s post-emergency stage. The SL-enriched fractions demonstrated greater phytotoxic activity when compared with the C. cardunculus leaf initial extract. The SL-enriched fractions had higher activity at root growth inhibition over the panel tested, doubling the activity in five of them at 800 ppm. Regarding the post-emergence bioassay, the SL-enriched fractions had a higher influence on the plants’ growth inhibition (67% at 800 ppm). The SL-effects on the plants’ metabolisms were evidenced. The total chlorophyll content was reduced by 65% at 800 ppm. Oxidative stress induction was observed because of the enhancement in MDA levels at 800 ppm compared to control (52%) and the decrease in SOD-specific activity from 4.20 U/mg protein (400 ppm) to 1.74 U/mg protein (800 ppm). The phytotoxic effects of the SL-enriched fractions suggest that they could be used for a future bioherbicide development.

Developmental-specific regulation promotes the free amino acids accumulation in chlorotic tea plants (Camellia sinensis)

Chlorophyll-deficient tea plant exhibits a significantly higher accumulation of free amino acids (FAAs) than normal tea plants. This study focused on the impact of leaf color and the developmental stage on FAAs in six tea germplasms while maintaining all other conditions. The total FAAs content initially increased as the leaf matured during the one-bud-two-leaves (1B2L) and one-bud-three-leaves (1B3L) stages in green germplasms, then decreased or stabilized in the one-bud-four-leaves (1B4L) stage. In contrast, chlorotic germplasms showed continuous FAAs’ content increase from 1B2L to 1B4L, thus being significantly positively correlated with total chlorophyll content. Interestingly, ethylamine content decreased with leaf maturation in both chlorotic and green germplasms, thus showing a significant negative correlation with L-theanine content only in chlorotic germplasms. Comparative RNA-seq analysis linked FAAs accumulation in chlorotic germplasm’s 1B3L to photosynthesis inhibition and in 1B4L to nitrogen assimilation promotion. Feeding experiments revealed higher L-theanine synthesis and degradation abilities in chlorotic shoots versus green shoots, with synthesis efficiency exceeding degradation efficiency. Overall, this study uncovers a developmental-specific FAAs accumulation pattern in chlorotic germplasms and offers novel insights into the precise regulation by leaf color and developmental stage.

The transcription factor TaNF-YB4 overexpression in wheat increases plant vigor and yield

Ensuring food security is a priority in developing countries. This study aimed to improve wheat yield by overexpressing the TaNF-YB4 transcription factor, which is involved in carbon assimilation and stress tolerance. An expression cassette for TaNF-YB4 was developed in a modified wheat transformation vector (pSB219) and examined through transient expression in Nicotiana tabacum, followed by Agrobacterium-mediated transformation of wheat variety FSD-2008. T0 transgenic plants were propagated to obtain T3 generation PCR-positive plants. Transgene expression was assessed in PCR-verified T2 plants using RT-PCR and qRT-PCR at six weeks post-germination. qRT-PCR analysis using the ΔΔCT method indicated higher TaNF-YB4 expression in transgenic lines than in the wild-type control plants. Improved agronomic and phenotypic traits were observed with a 6-36% increase in 1000-grain weight in the selected transgenic lines. Root architecture assessments demonstrated enhanced root length, surface area, and projected area in transgenic lines compared with wild-type plants. Additionally, notable variances in total chlorophyll, protein, and sugar content levels were observed between the transgenic lines and control plants, demonstrating statistical significance with a p-value ≤ 0.05. This study indicates that low-level constitutive expression of TaNF-YB4 can enhance wheat yield, presenting a viable strategy for improving wheat productivity.

INFLUENCE OF MICROBIAL FERTILIZERS ON MORPHOLOGICAL, PHYSIOLOGICAL AND VALUABLE ECONOMIC CHARACTER OF CHICKPEA (CICER ARIETINUM L.)

A field experiment was conducted to study the effects of Rhizobium 3 , Rhizobium 9 and PlantaStim microbial fertilizers on the morphological, physiological and valuable economic characters of chickpea (Сicer arietinum L.). All samples treated with microbial fertilizers showed positive results compared to the control variation. Efficiency of Rhizobium 3, among the microbial fertilizers, was higher. In the chickpea samples, treatment with Rhizobium 3 increased the total chlorophyll content by 14.91%, carotenoid content by 20%, plant biomass by 31.39%, grain number by 19.37%, productivity by 27.25%, total protein content by 25.29%, and amount of nodule by 2.07 times, compared to the control variation.

Nutrition for commercial flower production of Longiflorum asiatica (LA) hybrid under northern plains

The study was conducted during the winter seasons, comprising the various combinations of inorganic fertilizers (N, P2O5, and K2O) and organic manure (FYM). Treatment T24 [(25 t FYM+160 kg N+120 kg P2O5+100 kg K2O)/ha] emerged as the statistically significant treatment, outperforming others in respect of tallest plant (122.43 cm), leaf count per plant (79.33), leaf length (7.90 cm), and early flower bud initiation (28.01 days), bud initiation to colour shown (47.11 days), and colour shown to flower opening (6.10 days). This treatment also tended to show the longest flower retention on plant (15.30 days), number of flower buds per plant (4.20), bud length (8.96 cm), stalk length (110.10 cm), stalk diameter (0.96 cm), flower diameter (22.98 cm), total chlorophyll content (6.50 mg/g), leaf nitrogen (4.70%), potassium (4.10%), and net assimilation ratio (NAR) (0.0065 mg/cm2/ day). Treatment T23 [(25 t FYM+120 kg N+90 kg P2O5+75 kg K2O)/ha] proved next best treatment. The lowest value was recorded in T25 (Control). Overall, treatment T24 proved to be the most effective treatment statistically for the commercial flower production of LA hybrid lilium for northern Indian plains.

FOLIAR APPLICATION OF DEPOLYMERISED CHITOSAN ENHANCES THE GROWTH AND CONTENT OF POLYPHENOLS AND L-ASCORBIC ACID IN Eucomis autumnalis, AN ORNAMENTAL AND MEDICINAL PLANT

Chitosan and its derivatives are promising plant biostimulants with potentially broad applications in agriculture and horticulture. In this study, we determined the effect of the application method and dose of depolymerised chitosan on morphological characteristics and metabolite levels in Eucomis autumnalis, a medicinal and ornamental plant. Depolymerised chitosan (molecular weight ~154,500 g/mol, number average molecular weight ~22,800 g/mol and degree of deacetylation ~85%) was used at 50 and 100 mg/l by drenching plants or spraying. In general, depolymerised chitosan increased the length of plant leaves and roots, especially at the dose of 100 mg/l, and also increased the fresh weight of leaves, bulbs and roots, with a more potent effect found when depolymerised chitosan was applied as a foliar spray. In addition, spraying the plants with chitosan solution at 50 and 100 mg/l caused a significant increase in the total chlorophyll content, by 55.4% and 42.0%, respectively, and the total polyphenol content, by 77.7% and 59.0%, respectively, compared with the control. On the other hand, the biosynthesis of carotenoids was most favourably affected by the application of 100 mg/l depolymerised chitosan by drenching and 50 mg/l depolymerised chitosan by spraying. Foliar application of depolymerised chitosan led to an increase in leaf L-ascorbic acid content by an average of 36.4%, regardless of the dose. The results suggest that depolymerised chitosan applied as a foliar spray promoted the growth of E. autumnalis and contributed to increased biosynthesis of polyphenols, which may be a future means of obtaining metabolites in this species.

Integrative approaches to improve litchi (Litchi chinensis Sonn.) plant health using bio-transformations and entomopathogenic fungi

Bio-transformations refer to the chemical modifications made by an organism on a chemical compound that often involves the interaction of plants with microbes to alter the chemical composition of soil or plant. Integrating bio-transformations and entomopathogenic fungi into litchi cultivation can enhance symbiotic relationships, microbial enzymatic activity in rhizosphere, disease suppression and promote overall plant health. The integration of biological formulations and entomopathogenic fungi can significantly influence growth, nutrient dynamics, physiology, and rhizosphere microbiome of air-layered litchi (Litchi chinensis Sonn.) saplings. Biological modifications included, K-mobilizers, AM fungi, Pseudomonas florescence and Azotobacter chroococcum along with Metarhizium, entomopathogenic fungi have been used. The treatments included, T1-Litchi orchard soil + sand (1:1); T2-Sand + AM fungi + Azotobacter chroococcum (1:2:1); T3-Sand + Pseudomonas florecence + K-mobilizer (1:1:1); T4- AM fungi + K-mobilizers (1:1); T5, P. Florecence + A. chroococcum + K-mobilizer (1:1:1); T6-Sand + P. florecence (1:2) and T7-Uninoculated control for field performance. Treatments T4-T6 were further uniformly amended with drenching of Metarrhizium in rhizosphere. T2 application significantly increased resident microbe survival, total chlorophyll content and root soil ratio in seedlings. A. chroococcum, Pseudomonas, K-mobilizers and AM fungi increased in microbial biomass of 2.59, 3.39, 2.42 and 2.77 times, respectively. Acidic phosphatases, dehydrogenases and alkaline phosphatases were increased in rhizosphere. Leaf nutrients reflected through DOP were considerably altered by T2 treatment. Based on Eigen value, PCA-induced changes at biological modifications showed maximum total variance. The study inferred that the bio-transformations through microbial inoculants and entomopathogenic fungi could be an encouraging strategy to enhance the growth of plants, health and productivity. Such practices align well with the goals of sustainable agriculture through biological means by reducing dependency on chemical inputs. By delving into these aspects, the research gaps including microbial processes, competitive and symbiotic relationships, resistance in microbes and how complex interactions among bio-transformations, entomopathogenic fungi and microbes can significantly impact the health and productivity of litchi. Understanding and harnessing these interactions can lead to more effective and sustainable farming practices.

Determination of the Short-Term Drought Stress Tolerance of Three Barley Varieties Using Physiological and Biochemical Changes

Barley (Hordeum vulgare L.) is an important agricultural plant that can adapt to stress conditions. Abiotic stress factors significantly reduce growth, photosynthetic efficiency and metabolic processes in barley. Drought stress increases reactive oxygen species (ROS) in plant cells, and the antioxidant defense system reduces damage caused by overproduction of ROS. The aim of this study was to determine the physiological and biochemical effects of short-term drought stress on some barley cultivars (Kalaycı-97, Harman and Yaprak) grown in Turkey. In 21-day-old seedlings, short-term drought stress decreased the total chlorophyll content. The amount of total protein reduced in the Harman variety, while it increased by 19% in Kalaycı-97 and 27% in Yaprak. The H2O2 content decreased in Yaprak while increasing by 76% in the Kalaycı-97 variety. It was demonstrated that TBARS levels increased by 62% in Kalaycı-97 and 26% in Yaprak. In other ways, while drought stress caused a 48% decrease in APX activity in Kalaycı-97, it caused a 42% and 20% increase in APX activity in Harman and Yaprak, respectively. However, in Kalaycı-97 and Yaprak, CAT increased by 48% and 69%, respectively. These results indicate that Yaprak genotype is tolerant, Kalaycı-97 sensitive and Harman moderately tolerant to short term drought stress.

Optimization of Ultrasonication for Chlorella sp. Growth: Impacts on Biomass Productivity and Nutrient Utilization

Aims: This study aimed to investigate the effect of ultrasonic treatment of different durations on Chlorella sp. culture to analyze biomass concentration, biomass productivity and chlorophyll and macronutrients, such as nitrate and phosphate, which were added to the Chlorella sp. culture. Study Design: This investigation sought to optimize the duration of exposure of live microalgal culture to ultrasonic treatment to estimate economically significant biomass and pigments. Microalgal biomass has potential applications in biofuels, pharmaceuticals, and nutraceuticals, and is highly sought after by industry. Consequently, it is imperative to optimize this process for large-scale production. Chlorophyll pigment is not only crucial in the photosynthesis process but also serves as a high-value component in the food, cosmetic, and health industries. Furthermore, utilizing the optimized duration of ultrasonication treatment, residual nitrate and phosphate in the medium were analyzed, providing key insights into the nutrient consumption of Chlorella sp. under ultrasonication stress. Place and Duration of Study: The present investigation was conducted over 36 days to estimate the effect of ultrasonication on biomass, chlorophyll, nitrate and phosphorus concentration in Chlorella culture at the laboratory of Synthetic Ecology and Environment Biotechnology, Department of Environmental Science, School of Earth Sciences, Central University of Rajasthan, Bandarsindri, Ajmer. Methodology: In this study, the effects of ultrasonication on biomass and chlorophyll content were evaluated by treating Chlorella sp. cultures for 5, 10, and 15 min in addition to an untreated control group. Based on these results, an optimized ultrasonication duration of 5 min was selected for further analysis. During this phase, the nitrate and phosphorus contents in the culture medium were measured to investigate the influence of ultrasonication on these nutrient levels. All treatments were conducted in triplicate to ensure reproducibility of the results, with the mean and standard deviation calculated as measures of statistical reliability. The use of mean and standard deviation in triplicate tests ensure that the results are consistent and reproducible, hence providing a measure of statistical dependability. Results: The biomass concentration and biomass productivity concentration increased from 29.9 ± 0.00240 mg/L (control) to 66.8 ± 0.01485 mg/L, 1.275 ± 0.5033 (control) to 3.71 ± 0.4163 mg/L/day respectively. The highest total chlorophyll concentration was observed in the exponential phase (9 days of culture) which was 3.7772 ± 0.0500. There was a decrease in the concentrations of nitrate and phosphate throughout the culture period, with a total nitrate consumption of 38.5% and total phosphate consumption of 24%. Conclusion: Chlorophyll and biomass concentrations were maximized after 5 min of ultrasonic treatment, but declined with longer exposure. Nutrient analysis revealed a significant decrease in nitrate and phosphate concentrations over time, consistent with nutrient uptake by the growing cells and the subsequent accumulation of metabolites.

Physiological and proteomic responses of Posidonia oceanica to phytotoxins of invasive Caulerpa species

The invasive green algae Caulerpa taxifolia (M. Vahl) C. Agardh, 1817 and Caulerpa cylindracea Sonder, 1845 are widely diffused in the Mediterranean Sea, where they compete for space with the endemic seagrass Posidonia oceanica (Linnaeus) Delile, 1813, a keystone species in Mediterranean marine biodiversity. The present study aims to explore the possible effects of bioactive metabolites from the invasive algae on the seagrass, which may imply an allelopathic action. In particular, the study focuses on the effects of the algal alkaloid caulerpin and the sesquiterpene caulerpenyne. Changes in leaf growth, chlorophyll content, and leaf protein expression of P. oceanica genets under treatments were evaluated after 28 days of cultivation in mesocosms. Caulerpenyne strongly inhibited the growth of adult leaves and the formation of new ones, while inducing the elongation of the intermediate leaves and increased total chlorophyll content; on the contrary, caulerpin did not significantly influence leaf growth and the formation of new ones. A total of 107 differentially accumulated proteins common to the two treatments were also identified using the proteomic approach. Both molecules induced cells to maintain homeostasis, enhancing the amino acid metabolism or fatty acid biosynthesis. Despite these disruptions, P. oceanica demonstrated a more efficient response to stress induced by caulerpin, stimulating the biosynthesis of essential amino acids to maintain cellular homeostasis and mitigate damage caused by reactive oxygen species (ROS). Overall, obtained results supports the possible role of caulerpenyne, and not caulerpin, as an effector in allelopathic interactions among invasive Caulerpa species and P. oceanica in the Mediterranean.

Low-dose 60Co-γ-ray irradiation promotes the growth of cucumber seedlings by inducing CsSAUR37 expression.

Cucumber (Cucumis sativus L.) is a major vegetable crop grown globally, with a cultivation history of more than 3000years. The limited genetic diversity, low rate of intraspecific variation, and extended periods of traditional breeding have resulted in slow progress in their genetic research and the development of new varieties. Gamma (γ)-ray irradiation potentially accelerates the breeding progress; however, the biological and molecular effects of γ-ray irradiation on cucumbers are unknown. Exposing cucumber seeds to 0, 50, 100, 150, 200, and 250Gy doses of 60Co-γ-ray irradiation, this study aimed to investigate the resulting phenotype and physiological characteristics of seedling treatment to determine the optimal irradiation dose. The results showed that low irradiation doses (50-100Gy) enhanced root growth, hypocotyl elongation, and lateral root numbers, promoting seedling growth. However, high irradiation doses (150-250Gy) significantly inhibited seed germination and growth, decreasing the survival rate of seedlings. More than 100Gy irradiation significantly decreased the total chlorophyll content while increasing the malondialdehyde (MDA) and H2O2 content in cucumber. Transcriptome sequencing analysis at 0, 50, 100, 150, 200, and 250Gy doses showed that gene expression significantly differed between low and high irradiation doses. Gene Ontology enrichment and functional pathway enrichment analyses revealed that the auxin response pathway played a crucial role in seedling growth under low irradiation doses. Further, gene function analysis revealed that small auxin up-regulated gene CsSAUR37 was a key gene that was overexpressed in response to low irradiation doses, promoting primary root elongation and enhancing lateral root numbers by regulating the expression of protein phosphatase 2Cs (PP2Cs) and auxin synthesis genes.

Halotolerant phosphate solubilizing bacteria isolated from arid area in Tunisia improve P status and photosynthetic activity of cultivated barley under P shortage

Forty-seven (47) bacterial strains were isolated from soil of Gabes (an arid region in southern Tunisia) and were screened for their ability to produce Indole-3-Acetic Acid (IAA) and to solubilize phosphate (P). The characterization and molecular identification of the most successful P-solubilizing bacteria (PSB) were then carried out. When grown on suitable artificial media, the most salt-tolerant strains also showed the highest P solubilization capacity (up to 126.8 μg ml−1 of released phosphorus after 7 day incubation) and the strongest ability to produce IAA (up to 101.86 μg ml−1 after 3 day incubation). Overall, bacterial isolates displayed a different tolerance to varying pH, temperatures, and salinity. The molecular identification revealed that 11 strains belonged to three genera: Bacillus, Pseudomonas and Mesorhizobium. Inoculation of barley with P-solubilizing bacteria under tricalcium phosphate-induced P shortage significantly improved plant growth (biomass, shoot height, and root length) together with increasing total chlorophyll contents and photosynthetic activity. This was concomitant with (i) higher P uptake and translocation and (ii) increased phosphorus absorption and utilization efficiencies (PAE and PUE), which is indicative of a better plant P nutrition under P scarcity. Taken together, we provide strong arguments showing that bacteria native to extreme environments display PSB potential making them promising candidates to mitigate low Pi availability for crop plants.

Co-application of Parthenium biochar and urea effectively mitigate cadmium toxicity during wheat growth

Environmental contamination by cadmium (Cd), a highly toxic heavy metal, poses significant health risks to plants and humans. Biochar has been effectively used to promote plant growth and productivity under Cd stress. This study presents an innovative application of biochar derived from the invasive weed Parthenium hysterophorus to promote plant growth and productivity under Cd stress. Our study includes detailed soil and plant analyses, providing a holistic perspective on how biochar and urea amendments influence soil properties, nutrient availability, and plant physiological responses. To address these, we established seven treatments: the control, Cd alone (5 mg kg−1), biochar alone (5 %), urea alone (3 g kg−1), biochar with Cd, urea with Cd, and a combination of biochar and urea with Cd. Cd stress alone significantly reduced plant growth indicators such as shoot and root length, fresh and dry biomass, chlorophyll content, and grain yield. However, the supplementation of biochar, urea, or their combination significantly increased shoot length (by 48%, 34%, and 65%), root length (by 73%, 46%, and 70%), and fresh shoot biomass (by 4%, 31%, and 4%), respectively. This improvement is attributed to enhanced soil properties and improved nutrient absorption. The biochar–urea combination also enhanced Cd tolerance by improving total chlorophyll content by 14 %, 13 %, and 16 % compared to the control, respectively. Similaly, these treatments significantly (p < 0.05) boosted the activity of antioxidant enzymes such as catalase, peroxidase, and superoxide dismutase by 51 %, 30 %, and 51 %, respectively, thereby mitigating oxidative stress as a defensive mechanism. The Cd tolerance was improved by biochar, urea, and their combinations, which reduced Cd content in the shoots (by 60.5 %, 38.9 %, and 51.3 %), roots (by 47.5 %, 23.9 %, and 57.6 %), and grains (by 58.1 %, 30.2 %, and 38.3 %) relative to Cd stress alone, respectively. The synergistic effects of biochar and urea are achieved through improved soil properties, nutrient availability, activating antioxidant defense mechanisms, and minimizing the accumulation of metal ions in plant tissues, thereby enhancing plant defenses against Cd stress. Conclusively, converting invasive Parthenium weed into biochar and combining it with urea offers an environmentally friendly solution to manage its spreading while effectively mitigating Cd stress in crops.

Response of blueberry photosynthetic physiology to light intensity during different stages of fruit development.

To investigate the response of blueberry photosynthetic physiology to different light intensities during different stages of fruit development. In this study, four light intensity treatments (25%, 50%, 75% and 100% of full light) were set up to study the change rule of photosynthetic pigment content and photosynthetic characteristics of 'O'Neal' southern highbush blueberry leaves during the white fruiting stage (S1), purple fruiting stage (S2) and blue fruiting stage (S3) under different light intensity environments, and to explore the light demand and light adaptability of blueberry during different developmental stages of the fruit. The results showed that the chlorophyll and carotenoid contents of blueberry leaves showed an increasing trend with decreasing light intensity at all three stages of fruit development. The total chlorophyll content of blueberry leaves at 25% light intensity increased by 76.4% compared with CK during the blue fruiting stage; the maximum net photosynthetic rate (Pmax), light compensation point (LCP), light saturation point (LSP), rate of dark respirations (Rd), inter-cellular CO2 concentration (Ci), stomatal conductance (Gs), transpiration rate (Tr), net photosynthesis rate (Pn), and chlorophyll a/b showed a decreasing trend with decreasing light intensity. The Pn of blueberry leaves was highest under full light conditions at all three stages, and the Pn at 25% light intensity decreased by 68.5% compared with CK during the white fruiting stage Reflecting the fact that blueberries can adapt to low-light environments through increases in chlorophyll and carotenoids, but reduced light intensity significantly inhibited their photosynthesis. The photosynthetic physiology of blueberry showed a consistent pattern at all three stages, but there were some differences in the changes of photosynthetic parameters at different stages. The results of the study can provide theoretical references for the selection of sites and density regulation in blueberry production.

Evaluating the efficacy of microalgal-bacterial granular sludge system in lake water remediation.

The microalgal-bacterial granular sludge (MBGS) process is attracting attention as a green wastewater treatment technology. However, research on the application of MBGS in lake water remediation is limited. Thus, this experiment investigated the feasibility and the efficacy of the MBGS process for the treatment of natural lake water in a continuous-flow tubular reactor. The averageremoval efficiencies of COD, NH4+-N, NO3--N, NO2--N, TN, PO43--P, TP, and turbidity by MBGS system in the day/night cycles were 50.10/61.39%, 63.52/75.23%, 43.37/73.57%, 90.72/93.48%, 78.30/80.02%, 71.13/74.62%, 65.08/70.57%, 92.32/89.84%, respectively. As the experiment progressed, the total chlorophyll content in MBGS decreased as the granule size increased, while the extracellular polymeric substances content increased, suggesting that thelake water contributed to bacterial growth and favored the stability of MBGS. Moreover, the eukaryotic microorganisms were dominated by Chlorophyta and Rotifera, and prokaryotic microorganisms were dominated by Proteobacteria in MBGS. By promoting the decomposition of various organic compounds in the lake water and inhibiting sludge expansion, these microorganisms helpthe MBGS system tomaintain excellent granular characteristics and performance. Overall, the MBGS system proved to be a feasible option for the remediation of natural lake waters.

Performance Study of Betelvine (Piper betle Linn.) Cultivars under Varying Doses of Phytohormone-Triacontanol

Betel vine (Piper betle Linn.) belongs to the family Piperaceae. The experiment was carried out with two factorial randomized block design combining 3 replications and 18 no. of treatments. Adopted plant spacing was 50 cm x10 cm and plot to plot distance was 60 cm. Treatment Details: Factor 1: Triacontanol – 0.1% (T1), Triacontanol – 0.05% (T2), Triacontanol – 0% (T3), Factor 2: Cultivars: Utkal Sudam, Kali Bangla, Kotki, Simurali Bhabna, Simurali Gol Bhabna, Chalani local. Nutrients were applied as FYM (10 tonnes ha-1) and N:P:K::200:100:100 Kg ha-1year-1. Regarding the interaction effect of cultivar with the effect of Triacontanol, the cultivar Kotki treated with Triacontanol @ 0.1% (T1) recorded highest average vine elongation per month (32.83 cm). Whereas both the cultivar Kotki and Kali Bangla, when treated with Triacontanol @ 0.1% (T1) recorded maximum number of leaves per vine per year (4.60). The highest content of total Chlorophyll (3.89 mg/g) and essential oil (0.82%) was obtained from the cultivar Simurali Gole Bhabna treated with Triacontanol @ 0.1% (T1). The cultivar Utkal Sudam with Triacontanol @ 0.05% (T2) was observed highest Phenol content (142.58 mg GAE /100g). Maximum shelf life (18 days) was obtained from the cultivar Kali Bangla and Kotki treated with Triacontanol 0.1% (T1). From this experiment, highest benefit:cost ratio (3.03) was obtained from the cultivar Kali Bangla treated with Triacontanol @ 0.1%(T1) and lowest benefit:cost ratio (1.75) was recorded in cultivar Chalani local without the use of Triacontanol i.e. in control plot.