Increased Shoot Length Research Articles

Sustainable agronomic response of carbon quantum dots on Allium sativum: Translocation, physiological responses and alternations in chromosomal aberrations

The revolutionary growth in the usage of carbon quantum dots (CQDs) in different areas have ultimately directed their discharge in the environment and further augmented the exposure of agricultural crops to these released particles. Therefore, the aim of current study is to evaluate the uptake, translocation and phytotoxicity of blue emissive CQDs on Allium sativum plant. The genotoxicity and cytotoxicity assessment of CQDs towards Allium sativum roots was estimated as function of three different concentrations. Considering the role of CQDs in promoting seed germination at 50 ppm concentration, a greenhouse experiment was performed to evaluate their effect on plant growth. Systematic investigations have shown the translocation of CQDs and their physiological response in terms of increased shoot length wherein P-CQDs exhibited more accumulation into Allium sativum parts. Our investigations unfold the opportunity to utilize Aegle marmelos fruit derived CQDs as a growth regulator in variety of other food plants.

Differences in the metabolic and functional mechanisms used to tolerate flooding in Guazuma ulmifolia (Lam.) from flood-prone Amazonian and dry Cerrado savanna populations.

Flood tolerance is crucial to the survival of tree species subject to long periods of flooding, such as those present in the Amazonian várzea. Tolerance can be mediated by adjustments of metabolism, physiology and morphology, reinforcing the need to investigate the physiological and biochemical mechanisms used by tropical tree species to survive this stress. Moreover, such mechanisms may vary between populations that are subjected to differences in the frequency of flooding events. Here, we aimed to identify the mechanisms used by two populations of the tropical tree Guazuma ulmifolia (Lam.) to tolerate flooding: an Amazonian population frequently exposed to flooding and a Cerrado population, adapted to a dry environment. Young plants were subjected to a flooding of the roots and lower stem for 32days, followed by 17days of recovery. Amazonian plants exhibited greater increases in shoot length and higher maximum photosynthetic rate (Amax) compared with non-flooded plants from 7days of flooding onwards, whereas increased Amax occurred later in flooded Cerrado plants and was not accompanied by increased shoot length. Lactate accumulated in roots of Cerrado plants after 24h flooding, together with transcripts coding for lactate dehydrogenase in roots of both Cerrado and Amazonian plants. After 7days of flooding, lactate decreased and alcohol dehydrogenase activity increased transiently, together with concentrations of alanine, γ-aminobutyric acid and succinate, indicating activation of metabolic processes associated with low oxygen availability. Other amino acids also increased in flooded Cerrado plants, revealing more extensive metabolic changes than in Amazonian plants. Wetland and dryland populations of G. ulmifolia revealed the great capacity to tolerate flooding stress through a suite of alterations in photosynthetic gas exchange and metabolism. However, the integrated physiological, biochemical and molecular analyses realized here indicated that wetland plants acclimatized more efficiently with increased shoot elongation and more rapid restoration of normal metabolism.

Effect of biostimulants on soil characteristics, plant growth and yield of Pea (Pisum sativum L.) under field conditions

Because of the safe use of biostimulants as they are eco-friendly and modern technique for substituting chemical fertilizers which have negative impacts on the environment. Therefore, this study was conducted to determine the effect of two biostimulants, Spirulina platensis and Trifolium alexandrinum on soil properties, growth and yield of pea (Pisum sativum L.) grown under silty clay soil conditions. The field experiment was carried out during the winter season by applying each fertilizer to the cultivated soil at 3 concentrations (2.5, 5 and 10 g) either singly or in combination, forming 15 treatments in addition to control. It was found that the vegetative growth parameters as well as, yield components were significantly increased by two fertilizers applied singly or in combination. In comparison with control, the highest concentration of combined treatment (10 g) significantly increased shoot length, number of leaves, leaf area and number of branches by 145, 200, 300 and 100 % respectively. Furthermore, the combined treatment (10 g) showed the highest values of the number of pods (8), pod length (12 cm), no. of seeds (13) and dry weight of seeds (21.5 g), compared to control. Biostimulants boosted the plant growth and yield by enhancing the estimated parameters. Also, the physicochemical properties and mineral status of soil were improved after the application of the biostimulants. The current study indicates that the single and combined treatments of Spirulina platensis and Trifolium alexandrinum may potentially increase soil fertility and enhance the growth and yield of pea.

Suitable Materials for Paenibacillus sp. BSR1-1 Immobilization and Crop Growth Stimulation under Low Water Condition

Agricultural challenges due to a water shortage are factors limiting plant growth and productivity worldwide. One way to improve plant growth under unsuitable conditions is to use plant growth-promoting bacteria (PGPB). The objective of this study was to investigate the ability of PGPB to increase peanut, rice, and sweet corn growth under low water conditions. Suitable agricultural materials were selected first to be used in Paenibacillus sp. BSR1-1 immobilization. The materials were water hyacinth, reed, and coconut husk. Water hyacinth maintained the bacterial cell number when kept at either -4, 4, or 27-30 °C for both storage times, and water hyacinth soaked with a bacterial cell suspension prepared in 0.5 % ammonium sulfate ((NH4)2SO4) + 1 % glucose was the most suitable method to immobilize the bacterial cells. Paenibacillus sp. BSR1-1 with indole-3-acetic acid (IAA) and exopolysaccharide-producing abilities significantly increased root growth of peanuts under the low water condition. Root length and dry weight of inoculated peanut grown under low water conditions were 138.91 % and 156.51 % higher than uninoculated peanut, respectively. This bacterial isolate significantly increased rice shoot dry weight and root length under low and full water conditions. However, it only increased shoot length and root dry weight under the full water condition. Paenibacillus sp. BSR1-1 increased the dry weight of sweet corn under both conditions but only increased the root length of sweet corn under the full water condition. The shoot dry weight of inoculated sweet corn under the low water condition was 170.59 % higher than that of the un-inoculated sweet corn. When rice received Paenibacillus sp. BSR1-1 under the full water condition, and when peanuts received these bacteria under both conditions, they could produce more tillers and pods than the un-inoculated plants. Thus, Paenibacillus sp. BSR1-1 was an appropriate strain to use as a biofertilizer for agricultural proposes in water-limited areas.

Titanium Dioxide and Its Effect on Human Health and Environment- An in vitro Study

This work focuses on understanding the in-vitro effects of Titanium Dioxide (TiO2) led in the environment on human health, algae, and agriculture. Human dermal fibroblasts (HDF) from juvenile foreskin and human red blood cells (HRBC) were taken as a model to study the effect of TiO2 on human health in vitro. The study intended to define the toxic effect of TiO2 at 50 ppm, 100 ppm, and 200 ppm. The effect of TiO2 on the algae cyanobacterium as a model to analyze the algal toxicity effect i.e. was checked for freshwater toxicity at the concentration of TiO2 at 100 and 200 ppm was studied. The effect of TiO2 on the growth of microorganisms in wastewater was studied to determine its biodegradation in-vitro for 5 days using dissolved oxygen determination and the biological oxidation demand (BOD). Finally, phytotoxicity was monitored by observing the effect of TiO2 on wheat seed germination. It was found that TiO2 had no effect on HDF and HRBC at the tested concentrations as no cell death and hemolysis were observed when the cells were treated with TiO2. However, a statistically significant algal toxicity of 32.14 % was observed at 100 ppm and a 42.86 % (p<0.01) decrease in biomass was observed at 200 ppm. Additionally, there was no effect found on BOD of wastewater in the presence or absence of TiO2. The TiO2 had a positive effect on wheat seed germination in a dose-dependent manner. There was an increase in root length from 3.4 cm to 4.3 cm and 4.6 cm at 100 and 200 ppm of TiO2, respectively. Also, a slight increase in shoot length was observed at 100 ppm and 200 ppm. However, visible root thinning was a drawback observed. Hence, the present study gives an elaborative insight into the effects of Titanium Dioxide on human health and the environment.

Sugarcane plant growth promoting rhizo bacterial interaction for enhanced salinity tolerance

The present investigation was meted out on two promising sugarcane genotypes CoN-13072 and CoN-13073, were exposed to different NaCl levels to assess rhizobacterial interaction for salinity tolerance. From the shoot apex portion of two sugarcane genotypes tissue culture plantlets were developed. From that regenerated plantlets shifted to polyhouse and exposed to different NaCl levels to assess rhizobacterial interaction for salinity tolerance. Maximum shoot length (25.40 cm) was observed in genotype CoN-13073 under rhizobacterial inoculum at 2.0% NaCl concentration and maximum root length (12.40 cm) was observed at 0.0% and 1.5% NaCl concentration under rhizobacterial inoculum in genotype CoN-13072 and CoN-13073 respectively. Maximum shoot root ratio (2.60) and (2.40) was observed at 0.0% NaCl concentration with rhizobacterial inoculum within the rooting mixture of both the genotypes CoN-13073 and CoN-13072 respectively. High chlorophyll content index (5.48) and leaf area (41.20 cm2/plant) was observed in genotype CoN-13073 at 0.0% NaCl concentration under rhizobacterial inoculum. In genotypes CoN-13073 and CoN-13072, with a rise in NaCl concentration upto 2.0% and 1.5% respectively, increase in shoot length, leaf area and chlorophyll content index was observed as a result of increase in ACC deaminase activity. ACC deaminase activity and ethylene content within the plant body are negatively correlated. Increase in ACC deaminase activity results decrease in ethylene synthesis in plant body to avoid stress. Among the 2 genotypes, CoN-13073 found to be more salt tolerant at higher NaCl levels with the exhibition of low osmotic conductance, maximum leaf area with high chlorophyll content index.

Application of microbe-impregnated tannery solid waste biochar in soil enhances growth performance of sunflower.

Synergistic effect of biochar and microbes in soil enhances performance of plants. Hazardous tannery solid waste can be reduced by one-third in volume by conversion to biochar. A greenhouse trial was set up with soil having different doses of metal resistant microbe-impregnated biochar (MIBC) prepared from tannery solid waste. Consortia of autochthonous strains of Trichoderma and Bacillus were inoculated on BC and the behavior and fate of metals were evaluated for their bioavailability to sunflower. Sunflower was grown in pots for 80 days having six different amendments of tannery solid waste biochar (0-10% w/w) with and without Trichoderma and Bacillus consortia and its morphological and biochemical attributes as well as metal uptake were observed. The results illustrated that application of BC at 2% rate without inoculation increased the shoot length and dry biomass by 19.8% and 77.4%, respectively, while plant growth and performance were reduced at higher amendments of BC. However, application of MIBC with Trichoderma or/and Bacillus consortium significantly improved the plant attributes at all levels of amendment. The results indicated that MIBC having Trichoderma and Bacillus consortia at 10% rate increased shoot length and dry biomass by 65.3% and 516% compared to control without BC. Application of BC without inoculation reduced the uptake of Cu, Fe, and Ni and increased the mobilization of all other metals for uptake in sunflower. Mobilization and uptake of Cd, Cr, Cu, Ni, Pb, and Zn decreased with MIBC having Trichoderma and Bacillus consortia whereas that of Fe and Mg were noted. A considerable decrease in proline and total phenolic content was demonstrated by MIBC-grown sunflower. The data of metal fractionation in BC also supported the above findings. Therefore, MIBC can be used as a promising option for enhancing growth performance and ensuring the physiological safety of sunflower as an energy crop.

In-Depth Characterization of Plant Growth Promotion Potentials of Selected Alkanes-Degrading Plant Growth-Promoting Bacterial Isolates.

The use of plant growth-promoting rhizobacteria (PGPR) as a bioremediation enhancer in plant-assisted phytoremediation requires several steps, consisting of the screening, selection, and characterization of isolates. A subset of 50 bacterial isolates representing a wide phylogenetic range were selected from 438 morphologically different bacteria that were originally isolated from a petroleum hydrocarbon (PHC)-polluted site of a former petrochemical plant. Selected candidate bacteria were screened using six conventional plant growth-promoting (PGP) traits, complemented with the genetic characterization of genes involved in alkane degradation, as well as other pertinent functions. Finally, the bacterial isolates were subjected to plant growth promotion tests using a gnotobiotic approach under normal and stressed conditions. Our results indicated that 35 bacterial isolates (70%) possessed at least four PGP traits. Twenty-nine isolates (58%) were able to utilize n-hexadecane as a sole carbon source, whereas 43 isolates (86%) were able to utilize diesel as the sole carbon source. The presence of catabolic genes related to hydrocarbon degradation was assessed using endpoint PCR, with the alkane monooxygenase (alkB) gene found in 34 isolates, the cytochrome P450 hydroxylase (CYP153) gene found in 24 isolates, and the naphthalene dioxygenase (nah1) gene found to be present in 33 isolates. Thirty-six strains (72%) promoted canola root elongation in the growth pouch assay. After several rounds of screening, seven bacterial candidates (individually or combined in a consortium) were tested for canola root and shoot growth promotion in substrates amended by different concentrations of n-hexadecane (0%, 1%, 2%, and 3%) under gnotobiotic conditions. Our results showed that Nocardia sp. (WB46), Pseudomonas plecoglossicida (ET27), Stenotrophomonas pavanii (EB31), and Gordonia amicalis (WT12) significantly increased the root length of canola grown in 3% n-hexadecane compared with the control treatment, whereas Nocardia sp. (WB46) and Bacillus megaterium (WT10) significantly increased shoot length compared to control treatment at the same concentration of n-hexadecane. The consortium had a significant enhancement effect on root length compared to all isolates inoculated individually or to the control. This study demonstrates that the combination of PGPR traits and the PHC degradation potential of bacteria can result in an enhanced beneficial effect in phytoremediation management, which could lead to the development of innovative bacterial inoculants for plants to remediate PHC-contaminated soils.

Exploring biocontrol and growth-promoting potential of multifaceted PGPR isolated from natural suppressive soil against the causal agent of chickpea wilt

Chickpea is an important nutritive food crop both for humans and animals. Chickpea wilt caused by Fusarium oxysporum f.sp. ciceris (Foc) results in huge yield losses every year. Chickpea being a food crop requires the development of an eco-friendly bio-pesticide to effectively control the chickpea wilt disease. In this study, more than 50 bacterial stains isolated from the rhizosphere of healthy plants growing in wilt sick soil were examined for their Foc antagonist activities. Out of these, 17 strains showing > 90% growth inhibition of Foc were then characterized for their plant growth-promoting (PGP) and biocontrol traits. The biocontrol and PGP traits identified include amylase, hydrogen cyanide, protease, cellulase, chitinase activities, p-solubilization, nitrogen-fixing, and indole-3-acetic acid production. Two bacterial strains, IR-27 and IR-57, exhibiting the highest Foc proliferation inhibition and the PGP potential along with a consortium of four different strains (Serratia sp. IN-1, Serratia sp. IS-1, Enterobacter sp. IN-2, Enterobacter sp. IN-6) were used for controlling the chickpea wilt disease and growth promotion of the chickpea plants. Confocal laser scanning microscopy revealed their root colonization ability with partial or complete elimination of broken Foc mycelia and hyphae from roots. The bacterial inoculations particularly the consortium significantly suppressed the disease and improved the overall root morphology traits (root length, root surface area, root volume, forks, tips, and crossings), resulting in enhanced growth of the chickpea plants. Significant changes in growth (107% increase in root length, 23% increase in shoot length, and 54% increase in branches) in Foc-challenged plants were observed when inoculated with the consortium. Further investigations revealed that the chickpea plants inoculated with bacterial strains induced the expression of a number of key defence enzymes, including the phenylalanine ammonia lyase, peroxidase, polyphenol peroxidase, β-1,3 glucanase, which might have helped the plants to thwart the pathogen attack. These findings indicate the potential of our identified bacterial strains to be used as a natural biopesticide for controlling the chickpea wilt disease.

Characterization and cadmium detoxification dynamics of endophytic bacteria, isolated from rice plants

Over the past few decades, a special focus has been placed on plant endophytic bacteria's ability to improve plant responses to various stresses. We isolated bacteria from SWAT-1 rice variety and characterized them biochemically and morphologically. The isolates included seven from leaves, eight from roots, and five from stems. A total of 20 isolates were identified, of which four were gram-negative and sixteen were gram-positive. Eight of the isolates were catalase-positive, whereas twelve were catalase-negative. The highest production of indole-3-acetic acid (IAA) was recorded in IALIV (4.01 µg/ml), with the lowest production by IARIV (0.22 µg/ml). Similarly, IALIII and IASII produced the lowest (0.24 µg/ml) and highest (0.73 µg/ml) amylase respectively. IARVI and IASII showed maximum antimicrobial activity (27 mm) against Calcibacter and minimum activity (10 mm) against Xanthomonas. In terms of growth promotion, all isolates increased shoot length, root length, biomass production, and Cd uptake in plants. As compared to uninoculated plants, the inoculation of endophytes significantly improved (p < 0.05) the plant growth attributes in plants exposed to Cd stressors (7 mM and 12 mM). Generally, isolates have been shown to be useful as biocontrol agents and biofertilizers.

Seed priming with vermicompost leachate, Ecklonia maxima extract-Kelpak® and smoke-water induce heat stress amelioration and growth in Vigna unguiculata L. seedlings

With the human population increase, food production will be required to double. However, there is a direct correlation between prevalent abiotic stresses and yield reduction in crops. Cowpea (Vigna unguiculata) makes a staple meal in most diets worldwide, but its growth remains susceptible to stress. Biostimulants; vermicompost leachate (VCL), seaweed extract Kelpak® (KEL) and smoke-water (SW) are suggested as economical solutions with the potential to improve yield under abiotic stresses. Therefore, the aim of the present study was to investigate the effects of seed priming (SP) and non-priming (NP) with VCL, KEL and SW on germination and growth of cowpea (local cv. IT18) cultivated under 30, 35 and 40 °C. VCL 1:20 (v/v), KEL (0.6%) and SW 1:1000 (v/v) were more potent as priming germination cues under the three examined temperatures. Seed priming using the three biostimulants significantly (P ≤ 0.05) increased seedling vigour index, root length and fresh weight of 7-day-old seedlings under 30, 35 and 40 °C compared to non-primed controls. They also elicited significant increases in shoot length, leaf number, seedling area and reduced average germination time at 40 °C. KEL and SW-priming markedly increased stem diameter, seedling area, shoot length, leaf number, fresh and dry biomass after 28 d under 30 and 40 °C compared to control. However, SP inhibited root stimulation in cuttings. These results are encouraging and showcase the potential of the three stimulants for maintaining crop yields under heat stress and are relevant for other neglected staple crops in South Africa and globally.

Transcriptional regulation of cell growth and reprogramming of systemic response in wheat (Triticum turgidum subsp. durum) seedlings by Bacillus paralicheniformis TRQ65.

Bacillus paralicheniformis TRQ65 reprograms the gene expression patterns associated with systemic response to potentially facilitate its colonization and stimulate cell growth and plant biomass. Plant growth-promoting rhizobacteria (PGPR) carry out numerous mechanisms that enhance growth in seedlings, such as nutrient solubilization, phytohormone production, biocontrol activity, and regulation of induced systemic resistance (ISR) and acquired systemic resistance (ASR). Bacillus paralicheniformis TRQ65 is a biological and plant growth-promoting bacterium isolated from wheat (Triticum turgidum subsp. durum) rhizosphere. In this study, we performed a transcriptomic analysis of wheat seedlings inoculated with the native rhizobacterium Bacillus paralicheniformis TRQ65 (1 × 107cells∙g -1 of soil) at early development stages (GS15). A morphometrical assay was carried out to confirm growth promotion and after the cultivation period, TRQ65 was re-isolated to define inoculum persistence. Inoculated seedlings showed a significant (P < 0.05) increase in shoot length (93.48%) and dry weight in both shoot (117.02%) and root (48.33%) tissues; also, the strain persisted in the soil at 1.4 × 107UFC∙g-1 of soil. A total of 228 differentially expressed genes (DEGs) (FDR < 0.05 and |log2 fold change|≥ 1.3) were observed in response to TRQ65 inoculation, of which 185 were down-regulated and 43 were up-regulated. The transcriptional patterns were characterized by the regulation of multidimensional cell growth (ROS, Ca+2 channel, and NADPH oxidases activity), suppression of defense mechanism (PR proteins, PDFs, ROS, transcription factors), induction of central stimuli receptors (RALF, WAK, MAPK), carbohydrate metabolism (invertase activity) and phytohormone-related transport (ABCG transporter and AAAP). These results suggest that B. paralicheniformis TRQ65 is a promising bioinoculant agent for increasing wheat growth and development by reprogramming ISR and ASR simultaneously, suppressing defense mechanisms and inducing central stimuli response.

Role of nanosilicab to boost the activities of metabolites in Triticum aestivum facing drought stress

This study was designed to assess the effect of nanosilicab fertilizer on Triticum aestivum under drought stress. The plants were grown in pots having the soil incubated with SiO2 NPs, biofertilizer and nanosilicab. The experimental design was completely randomized design and drought stress was applied at stem elongation stage. Plants were maintained in the pots till the collection of yield. Nanosilicab enhanced the germination percentage, germination index, and germination vigor index by 23.07%, 14.49%, and 93.10% under control and 14.42%, 10.52%, and 46.15% under drought stress. In the pot experiment, the soil was treated with 150 mg/kg silicon dioxide nanoparticles (SiO2), 1% biofertilizer and, 1% nanosilicab before sowing. Nanosilicab increased shoot length and root length by 34.77%, and 16.88% under control and 30.58%, and 21.56% under stress conditions, respectively. It also increased photosynthetic pigments, osmolytes content, relative water content, membrane stability index, phenol, and flavonoid content. The increase in antioxidant activity was significant by the application of nanosilicab i.e. the augmentation in catalase, peroxidase, and superoxide dismutase was 68.65%, 83.69%, and 85.99%, respectively. It also increased indole acetic acid and cytokinin by 22.28% and 14.79% in comparison to control. The improvement in hundred-grain weight and grains per spike by the use of nanosilicab was 36.25%, and 38.76% under control, and 27.47%, and 22.59% under stress conditions. The positive effect of nanosilicab on the roots of the plants improved the growth of plants significantly and this fertilizer showed potential for application on crops.

Microbial consortia inoculation of woody legume Erythrina brucei increases nodulation and shoot nitrogen and phosphorus under greenhouse conditions

The legume-rhizobium symbiosis provides Nitrogen (N), while Legume-AMF symbiosis improves Phosphorus (P) supply to plants. This research was conducted to evaluate the symbiotic effectiveness of the Bradyrhizobium spp. and consortial inoculation of plant growth promoting bacteria -Bradyrhizobium shewense (AU27) and Acinetobacter soli (AU4), and arbuscular mycorrhizhal fungi Glomus sp.1 (AMF1) and Acaulospora sp.1 (AMF2), on growth, production and shoot N and P content of Erythrina brucei.The bacterial and mycorrhizal species were evaluated for phyto-beneficial properties in the greenhouse as individual as well as consortial inoculation.. All Bradyrhizobium species were effective for symbiotic nitrogen fixation. Consortial inoculations comprising of B. shewense (AU27) + A. soli (AU4) + Glomus sp.1 (AMF1) + Acaulospora sp.1 (AMF2) (T7) increased shoot length and shoot dry weight by 140% and 268%, respectively compared to un-inoculated control. Inoculations that involved B. shewense (AU27) + A. soli (AU4) increased shoot nitrogen by 260%, and 1200% increment of shoot P was recorded with inoculations of B. shewense (AU27) + Glomus sp.1 (AMF1) compared to un-inoculated control. These microbial inputs could be candidates for growth enhancement and shoot nitrogen and phosphorus improvement in Erythrina brucei and also as sustainable and eco-friendly agriculture input.

In Vitro Propagation of the Dendrobium anosmum Lindl. Collected in Vietnam

Hoa Binh province is one of the best places for orchids in Vietnam. The climate and environment of Hoa Binh province are favorable for the development of orchids, especially rare indigenous ones. Dendrobium anosmum Lindl., which stands out because of the unique fragrance and colors, is one of the most popular varieties in Hoa Binh province. To meet the increasing demands of the industrial market as well as to contribute to the preservation and development of genetic resources of Dendrobium sp. in Hoa Binh province, propagating D. anosmum Lindl. is a crucial step. Plant tissue culture, which has been applied to improve reproducibility of orchids for many years, is still an effective method, especially for large-scale propagation. Studies on in vitro propagation of D. anosmum Lindl. from Hoa Binh province showed that growth regulators (BA, kinetin, α-NAA) did not have a significant effect on protocorm initiation because D. anosmum Lind. from Hoa Binh province already has a high rate of regeneration. However, MS medium + 1.0 mg/L kinetin + 0.5 mg/L α-NAA + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the optimal medium to increase shoot length. The MS medium + 1.0 g activated charcoal + 30 g sucrose + 8.0 g agar per liter, pH 5.7–5.8 was the most suitable medium for shoot growth—after 6 weeks of culture, the average shoot length was 1.09 cm, the average number of leaves was 6.13, the average number of roots was 3.17, and the average root length was 1.11 cm—about 3.3, 4.17, 3.41, and 1.67 times higher, respectively, than in the control (without activated charcoal).

Efficacy of authentic bio-nematicides against the root-knot nematode, Meloidogyne javanica infecting tomato under greenhouse conditions

The root-knot nematode (RKN), Meloidogyne javanica is considered one of the most widely distributed and economically damaging plant-parasitic nematodes worldwide. Given the exacerbation of the environmental pollution problem with chemical nematicides, the use of biological nematicides is one of the most acceptable alternative methods in nematode management by the farming community. Four bio-nematicides namely: NT (Steinernema feltiae), MM (Ascophyllum nodosum and Bacillus amyloliquefaciens), GA sol+ (A. nodosum, B. amyloliquefaciens, and Trichoderma harzianum), and Ortie-Prele (aqueous extract of nettle and horsetail (Equisetum arvense)) were evaluated for their efficacy against M. javanica infecting tomato plants under greenhouse conditions. Their efficiencies were compared to a positive control and NemGuard Granules (garlic granule extract) as a standard nematicide. Treatment effects on the growth parameters were also examined. All tested treatments gave high nematicidal effect, except for the Ortie-Prele. The highest reductions in root galling (63%), as well as the number of egg masses (98%), eggs (96%), second-stage juveniles (J2s) (93%), and the reproduction factor (RF = 2.36) were obtained by the NT treatment, which was superior to the efficacy of the standard nematicide 52.63%, 91.58%, 88.30%, and 92.07%, respectively. The Ortie-Prele treatment gave the lowest reduction for the previous nematode criteria 0%, 53.96%, 12.39%, and 11.84%, respectively. On the other hand, all treatments, significantly improved tomato growth parameters; plant length, shoot fresh weight and, root systems when compared to the standard nematicide (Nemguard Granules), and the positive control. The highest increase in shoot length (30.90%), root length (58.13%) and shoot weight (30.98%) were obtained by GA sol+, while Ortie-Prele recorded the highest increase in root weight systems (91.89%). Therefore, our results indicated that NT, MM, and GA sol + proved to be crucial components for an integrated management of M. javanica in tomato crops.

Mitigation of Commercial Food Waste-Related Salinity Stress Using Halotolerant Rhizobacteria in Chinese Cabbage Plants

The use of commercial food waste in the Korean agricultural industry is increasing due to its capacity to act as an ecofriendly fertilizer. However, the high salt content of food waste can be detrimental to plant health and increase salinity levels in agricultural fields. In the current study, we introduced halotolerant rhizobacteria to neutralize the negative impact of food waste-related salt stress on crop productivity. We isolated halotolerant rhizobacteria from plants at Pohang beach, and screened bacterial isolates for their plant growth-promoting traits and salt stress-mitigating capacity; consequently, the bacterial isolate Bacillus pumilus MAK9 was selected for further investigation. This isolate showed higher salt stress tolerance and produced indole-3-acetic acid along with other organic acids. Furthermore, the inoculation of B. pumilus MAK9 into Chinese cabbage plants alleviated the effects of salt stress and enhanced plant growth parameters, i.e., it increased shoot length (32%), root length (41%), fresh weight (18%), dry weight (35%), and chlorophyll content (13%) compared with such measurements in plants treated with food waste only (control). Moreover, relative to control plants, inoculated plants showed significantly decreased abscisic acid content (2-fold) and increased salicylic acid content (11.70%). Bacillus pumilus MAK9-inoculated Chinese cabbage plants also showed a significant decrease in glutathione (11%), polyphenol oxidase (17%), and superoxide anions (18%), but an increase in catalase (14%), peroxidase (19%), and total protein content (26%) in comparison to the levels in control plants. Inductively coupled plasma mass spectrometry analysis showed that B. pumilus MAK9-inoculated plants had higher calcium (3%), potassium (22%), and phosphorus (15%) levels, whereas sodium content (7%) declined compared with that in control plants. Similarly, increases in glucose (17%), fructose (11%), and sucrose (14%) contents were recorded in B. pumilus MAK9-inoculated plants relative to in control plants. The bacterial isolate MAK9 was confirmed as B. pumilus using 16S rRNA and phylogenetic analysis. In conclusion, the use of commercially powered food waste could be a climate-friendly agricultural practice when rhizobacteria that enhance tolerance to salinity stress are also added to plants.

Response of Rhizobacterial strains and organic amendments on chickpea growth.

Plant Growth Promoting Rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and promote plant growth through a variety of mechanisms such as phosphate solubilization, phytohormones production, antifungal activity and also improve plant growth and yield. Field experiment was carried out to investigate the residual effect of organic amendments plus soil microbes along with integrated nutrient management. (PGPR) are important soil organism that promotes plant growth and yield root colonization is an example of a direct and indirect mechanism. The treatments included control, (inorganic fertilizer and no organic fertilization).Five bacterial strains were identified morphologically and biochemically screened from the rhizospheres of chickpea, lentil, barseem, mungbean, and sesame. The experiment was conducted at the Arid Zone Research Center in D.I.Khan (Pakistan). The majority of isolates resulted in significant increase in shoot length, root length, and dry matter production of Cicer arietinum seedlings' shoot and root. The experiment represented that isolates treated plots with rhizobium strain inoculation resulted in greater plant height (35.000 cm) and nodule count (38.00) No of pods per plant-1 (44.66) when compared to the control treatment, While (Mesorhizobium cicero) along with organic amendments showed significant response the greater root length (50 cm) was observed in T4 treatment. The Performance of rhizobial strains on chickpea germination in an arid environment was found to significantly increase crop germination percentage. This combination thus increases nitrogen and phosphorus uptake in inoculation treated plots. The study found that plots with inoculation treatments yielded significantly higher than non-treated plots Treatment with Mesorhizobium Cicero and compost resulted in a higher grain yield (8%) as compared to the control. The greater grain yield was observed in Treatment T4 (183.67).The result showed that use of PGPR have the potential to increase nutrient absorption from soil while improved growth of chickpea.

Evaluation of Symbiotic Association between Various Rhizobia, Capable of Producing Plant-Growth-Promoting Biomolecules, and Mung Bean for Sustainable Production

To feed the increased world population, sustainability in the production of crops is the need of the hour, and exploration of an effective symbiotic association of rhizobia with legumes may serve the purpose. A laboratory-scale experiment was conducted to evaluate the symbiotic effectiveness of twenty wild rhizobial isolates (MR1–MR20) on the growth, physiology, biochemical traits, and nodulation of mung bean to predict better crop production with higher yields. Rhizobial strain MR4 resulted in a 52% increase in shoot length and 49% increase in shoot fresh mass, while MR5 showed a 30% increase in root length, with 67% and 65% improvement in root fresh mass by MR4 and MR5, respectively, compared to uninoculated control. Total dry matter of mung bean was enhanced by 73% and 68% with strains MR4 and MR5 followed by MR1 and MR3 with 60% increase in comparison to control. Rhizobial strain MR5 produced a maximum (25 nodules) number of nodules followed by MR4, MR3, and MR1 which produced 24, 23, and 21 nodules per plant. Results related to physiological parameters showed the best performance of MR4 and MR5 compared to control among all treatments. MR4 strain helped the plants to produce the lowest values of total soluble protein (TSP) (38% less), flavonoids contents (44% less), and malondialdehyde (MDA) contents (52% less) among all treatments compared to uninoculated control plants. Total phenolics contents of mung bean plants also showed significantly variable results, with the highest value of 54.79 mg kg−1 in MR4 inoculated plants, followed by MR5 and MR1 inoculated plants, while the minimum concentration of total phenolics was recorded in uninoculated control plants of mung bean. Based on the results of growth promotion, nodulation ability, and physiological and biochemical characteristics recorded in an experimental trial conducted under gnotobiotic conditions, four rhizobial isolates (MR1, MR3, MR4, and MR5) were selected using cluster and principal component analysis. Selected strains were also tested for a variety of plant-growth-promoting molecules to develop a correlation with the results of plant-based parameters, and it was concluded that these wild rhizobial strains were effective in improving sustainable production of mung bean.

Lead-Tolerant Bacillus Strains Promote Growth and Antioxidant Activities of Spinach (Spinacia oleracea) Treated with Sewage Water

Irrigation with sewage-contaminated water poses a serious threat to food security, particularly in developing countries. Heavy metal tolerant bacteria are sustainable alternatives for the removal of wastewater contaminants. In the present study, four lead (Pb)-tolerant strains viz. Bacillus megaterium (N8), Bacillus safensis (N11), Bacillus sp. (N18), and Bacillus megaterium (N29) were inoculated in spinach and grown in sewage water treated earthen pots separately and in combination with canal water. Results showed that Pb-tolerant strains significantly improved plant growth and antioxidant activities in spinach and reduces metal concentration in roots and leaves of spinach plants irrigated with treated wastewater. Strain Bacillus sp. (N18) followed by B. safensis (N11) caused the maximum increase in shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, and leaf area compared to the uninoculated control of sewage water treated plants. These strains also improved antioxidant enzymatic activity including catalase, guaiacol peroxidase dismutase, superoxide dismutase, and peroxidases activities compared to the uninoculated control under sewage water conditions. Strain Bacillus sp. (N18) followed by B. safensis (N11) showed the highest reduction in nickel, cadmium, chromium, and Pb contents in roots and leaves of spinach compared to the uninoculated control plants treated with the sewage water. Such potential Pb-tolerant Bacillus strains could be recommended for the growth promotion of spinach after extensive evaluation under field conditions contaminated with wastewater.