Influence of Pseudomonas sp. NEEL19 Expelled Volatile Compounds on Growth and Development of Crop Seedlings

Soil and water contamination by heavy metals, such as chromium, poses a significant food safety concern. Scientists are suggesting various remedial strategies to address this burning problem worldwide. Chromium-VI causes detrimental morphological, physiological and metabolic impacts on plant system. In this research, we examined how citric acid influences the reduction of stress caused by Cr-VI stress in mung bean (Vigna radiata) seedlings. Results showed that Cr exposure led to diminished plant growth, decrease in the photosynthetic pigment levels and antioxidant enzyme activity. Addition of citric acid with chromium improved shoot and root length, total chlorophyll, chlorophyll a, chlorophyll b, carotenoids, anthocyanin, total sugar and reducing contents, phenol and flavonoid levels in plants. Furthermore citric acid supplementation increases ROS scavenging enzyme activities while proline, MDA and H2O2 levels declined. These results concluded that citric acid boosted the antioxidant system of test seedlings to diminish the toxicity of Chromium-VI. Hence, application of exogenous citric acid might be a useful strategy for alleviating Cr-VI toxicity in mung bean seedlings in Cr contaminated field.

Silicon and nitric oxide interplay alleviates copper induced toxicity in mung bean seedlings

Different physiological and biochemical responses in mung bean (Vigna radiata L.) and tomato (Solanum lycopersicum L.) seedlings induced by graphene quantum dots (GQDs) (250–1500 mg L−1) were studied. Results showed that both seeds exposed to GQDs can still germinate normally. However, the growth of the seedlings after germination was adversely affected by the GQDs, and mung bean was more sensitive than tomato. In hydroponic experiments, the appropriate concentration of GQDs enhanced the accumulation of chlorophyll in mung bean (250–1250 mg L−1) and tomato (250–500 mg L−1) seedlings after exposure for 2 weeks. High concentrations of GQDs (1000–1500 mg L−1) led to an increase in the H2O2, malondialdehyde (MDA), proline, glutathione (GSH) levels, as well as increased catalase (CAT) and glutathione reductase (GR) activities in seedlings of both species. In addition, the migration of GQDs into plants was observed. Results showed that high concentrations of GQDs had an adverse effect on the growth of both plants, and mung bean seedlings were more sensitive than tomato seedlings. In addition, the problem of nanocontamination was suggested and the resulting food safety problems warrant further investigation.

A role for brassinosteroids in the amelioration of aluminium stress through antioxidant system in mung bean ( Vigna radiata L. Wilczek)

The present study investigated the effect of ferulic acid (FA; 0–1000 µM) on early growth, and rhizogenesis in mung bean (Vigna radiata) hypocotyls and associated biochemical changes. FA severely affected the radicle elongation and number of secondary roots after 72 h. The root and shoot length, number and length of secondary roots, and seedling dry weight of one-week-old seedlings of mung bean were decreased by 64%. The rooting potential (percent rooting, number and length of adventitious roots) of mung bean hypocotyls under in vitro conditions was significantly inhibited in response to 1–100 µM FA. At 1000 µM there was complete cessation of rooting. FA caused a reduction in the contents of water-soluble proteins and endogenous total phenolics, whereas the activities of proteases, peroxidases, and polyphenol peroxidases increased. The study concludes that FA inhibits root growth and development, and in vitro rooting process in mung bean by interfering with biochemical processes that are crucial for root formation.

Cadmium (Cd) is one of the foremost phytotoxic elements. Its proportion in agricultural soil is increasing critically due to anthropogenic activities. Cd stress is a major crop production threat affecting food security globally. Triacontanol (TRIA) is a phytohormone that promotes growth, development, and metabolic processes in plants. The current study explicates the mitigation of Cd toxicity in Vigna radiata L. (mung bean) seedlings through the application of TRIA by a seed priming technique under Cd stress. The role of TRIA in improving metabolic processes to promote Vigna radiata (mung bean, green gram) vegetative growth and performance under both stressed and unstressed conditions was examined during this study. To accomplish this, three doses of TRIA (10, 20, and 30 µmol L−1) were used to pretreat V. radiata seeds before they were allowed to grow for 40 days in soil contaminated with 20 mg kg−1 Cd. Cd stress lowered seed germination, morphological growth, and biomass in V. radiata plants. The maximum root and shoot lengths, fresh and dry weights of roots, and shoot and seed germination rates were recorded for TRIA2 compared with those of TRIA1 and TRIA3 under Cd stress. In Cd-stressed V. radiata plants, TRIA2 increased the content of chlorophyll a (2.1-fold) and b (3.1-fold), carotenoid (4.3-fold), total chlorophyll (3.1-fold), and gas exchange attributes, such as the photosynthetic rate (2.9-fold), stomatal conductance (6.0-fold), and transpiration rate (3.5-fold), compared with those in plants treated with only Cd. TRIA seed priming increased nutrient uptake (K1+, Na1+, Mg2+, and Zn2+), total phenolic content, total soluble protein content, and DPPH (2,2-diphenyl-1-picrylhydrazyl) activity. Additionally, TRIA2 significantly reduced the quantity of Cd in the plants (3.0-fold) and increased the metal tolerance index (6.6-fold) in plants contrasted with those in the Cd-treated plants. However, TRIA2 promoted plant growth and biomass production by lowering Cd-induced stress through modifying the plant antioxidant machinery and reducing oxidative stress. The improved yield characteristics of V. radiata seedlings treated with TRIA suggest that exogenous TRIA may be used to increase plant tolerance to Cd stress.

BackgroundChromium (Cr) contamination in soil poses a serious hazard because it hinders plant growth, which eventually reduces crop yield and raises the possibility of a food shortage. Cr’s harmful effects interfere with crucial plant functions like photosynthesis and respiration, reducing energy output, causing oxidative stress, and interfering with nutrient intake. In this study, the negative effects of Cr on mung beans are examined, as well as investigate the effectiveness of Azospirillum brasilense and salicylic acid in reducing Cr-induced stress.ResultsWe investigated how different Cr levels (200, 300, and 400 mg/kg soil) affected the growth of mung bean seedlings with the use of Azospirillum brasilense and salicylic acid. Experiment was conducted with randomized complete block design with 13 treatments having three replications. Significant growth retardation was caused by Cr, as were important factors like shoot and root length, plant height, dry weight, and chlorophyll content significantly reduced. 37.15% plant height, 71.85% root length, 57.09% chlorophyll contents, 82.34% crop growth rate was decreased when Cr toxicity was @ 50 µM but this decrease was remain 27.80%, 44.70%, 38.97% and 63.42%, respectively when applied A. brasilense and Salicylic acid in combine form. Use of Azospirillum brasilense and salicylic acid significantly increased mung bean seedling growth (49%) and contributed to reducing the toxic effect of Cr stress (34% and 14% in plant height, respectively) due to their beneficial properties in promoting plant growth.ConclusionsMung bean seedlings are severely damaged by Cr contamination, which limits their growth and physiological characteristics. Using Azospirillum brasilense and salicylic acid together appears to be a viable way to combat stress brought on by Cr and promote general plant growth. Greater nutrient intake, increased antioxidant enzyme activity, and greater root growth are examples of synergistic effects. This strategy has the ability to reduce oxidative stress brought on by chromium, enhancing plant resistance to adverse circumstances. The study offers new perspectives on sustainable practices that hold potential for increasing agricultural output and guaranteeing food security.

Aluminium (Al) is one of the major constraints reducing the growth and productivity of many crops in acidic soils throughout the world. In order to explore a possible measure to counter Al toxicity in plants salicylic acid (SA) was used as a treatment in this investigation. The seedlings of mung bean were grown in a plant growth chamber under controlled conditions in a sand culture. The seedlings were subjected to Al (0.0, 1.0 or 10.0 mM) stress, at 1 week old stage and were sprayed with 0 or 10−5 M of SA, at 14 day stage. The analysis of the plants at the completion of 3 weeks of growth revealed that the presence of Al in the nutrient medium caused a sharp reduction in growth (length, fresh and dry mass of root and shoot), the activity of carbonic anhydrase (E.C. 4.2.1.1), relative water content, water use efficiency, chlorophyll content and the rate of photosynthesis. However, the activity of antioxidative enzymes [catalase (E.C. 1.11.1.6), peroxidase (E.C. 1.11.1.7) and superoxide dismutase (E.C. 1.15.1.1)] in leaves and the content of proline, both in leaves and roots increased in the Al stressed plants. The spray of SA, in absence of Al strongly favoured the above parameters and also improved them in the plants grown under Al stress. Moreover, SA caused a further stimulation of antioxidative enzymes and proline content, which were already enhanced by Al stress. This implies that the elevated level of proline in association with antioxidant system, at least in part, was responsible for the amelioration of Al stress in mung bean seedlings.

Sustainable alternatives to herbicides, agrochemicals, and other synthetic molecules are imperative for the ecological sustainability in the line of United Nations Sustainable Development Goals (SGD) goals. Natural aqueous extracts from different plant species are important sources of biomolecules that can be used to holistically manage crops by improving germination and plant development. The objective of this study was to evaluate the application of two aqueous extract preparations of Verbesina sphaerocephala on the germination and development of tomato and mung bean seedlings. Infusion and maceration extracts were prepared using V. sphaerocephala leaves at different concentrations (0.25, 0.75, and 1.5 g/l). The effects on seed germination and seedling development were evaluated under nursery conditions. The germination percentage of tomato seeds was significantly reduced following the application of all extracts, which was considered an allelopathic effect. The opposite results were observed in mung bean seeds. Seedling development also differed between species following extract application, although the development of certain agronomic variables, such as stem height, root length, and fresh weight, were favored in both in tomato and mung bean. From the study, it may be conclude that V. sphaerocephala extracts delay germination during the first three days of tomato growth, however, they promote optimum seedling development both in tomato and mung bean.

The nanotechnology revolution is developing daily all over the world. Soil-borne fungi cause a significant yield loss in mung beans. Our study was performed to identify the impact of different concentrations of MgO nanoparticles (MgONPs) and to assess the prevalence of Fusarium solani (F. solani) and Fusarium oxysporum (F. oxysporum) in mung bean plants under in vivo conditions and, subsequently, the remaining impacts on soil health. In vitro studies revealed that MgONPs could inhibit fungal growth. Mung bean plants treated with MgONPs showed a promotion in growth. The obtained MgONPs were applied to the roots of 14-day-old mung bean plants at a concentration of 100 µg/mL. The application of MgONPs at a concentration of 100 µg/mL caused an increase in mung bean seedlings. Compared to the control treated with water, plants exposed to MgONPs at 100 µg/mL showed improvements (p < 0.05) in shoot fresh weight (28.62%), shoot dry weight (85.18%), shoot length (45.83%), root fresh weight (38.88%), root dry weight (33.33%), root length (98.46%), and root nodule (70.75%). In the greenhouse, the severity of disease caused by F. solani decreased from approximately 44% to 25% and that by F. oxysporum from 39% to 11.4%, respectively. The results of this study confirm that the temporal growth of the soil microbial biomass was partially reduced or boosted following the nanoparticle drenching addition and/or plant infections at higher concentrations of 50 and 100 µg/mL while there was no significant decrease at the lowest concentration (25 µg/mL). The current research helps us to better understand how nanoparticles might be used to prevent a variety of fungal diseases in agricultural fields while avoiding the creation of environmental hazards to soil health.

Abstract: Both protein and starch hydrolysis contribute to the effective mobilization of seed reserves to trigger seed germination. We studied the activities of hydrolytic enzymes in germinating seeds of mung bean (Vigna radiata) exposed to cadmium stress at 0, 25, 50, 75, 100 mg.L-1. Exposure to Cd stress decreased the seed germination rate and early seedling growth traits, including root and shoot length and plant fresh and dry biomass compared to control. The adverse effects of Cd were more prominent in terms of shoot length than root length. Seedling α-amylase and protease activities exhibited significant reductions with increasing Cd dose. We also recorded Cd-induced reduction in total soluble proteins and sugars while the concentration of free amino acids exhibited an increase. Above all, a decrease in the hydrolysis process of reserve carbohydrates, proteins and impaired reserve translocation contributed to the inhibition of seedlings’ germination and early growth traits.

Plant growth and development rely on various factors, including mineral nutrients. Some are macronutrients like nitrogen, phosphorus, and potassium, whereas some are micronutrients like iron, magnesium, zinc, and a few vitamins. This experimental attempt was to check the stimulatory effect of zinc nanoparticles on pulse plant growth. The study was conducted on the green synthesis of zinc oxide nanoparticles using Coriandrum sativum leaves extract. The characterization of zinc oxide nanoparticles was studied using the X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope technique (TEM). The effect of zinc oxide nanoparticles as a fertilizer on pulses plant (Bengal gram, Turkish gram, and green grams) was studied in vitro. The seed germination rate, length of root and shoot, fresh weight, dry weight, and protein and chlorophyll content were measured in different media for assessment of zinc oxide nanoparticle’s growth stimulatory effects. The green synthesis of zinc oxide nanoparticles was confirmed with a size around 100 nm by transmission microscope technique. The germination rate of plants was 100% in MS media and MS media + nanoparticles. The present study found that the root length, shoot length, and weight were higher in MS media + nanoparticles followed by MS media, MS media only with nanoparticles, and MS media without zinc, respectively. It is found that the zinc oxide nanoparticles support seed germination and plant growth and also increase the protein and chlorophyll content. Significantly enhanced growth and development were evident in green gram and Turkish gram compared to that in Bengal gram in media treated with zinc oxide nanoparticles. The protein estimation results showed that the content was higher after 7 days in plants of Bengal gram (1.23 mg/ml), Turkish gram (1.19 mg/ml), and green gram (1.26 mg/ml) than that in roots and shoots. The application of MS media + ZnO nanoparticles results showed that chlorophyll content 12.6 mg/l was observed in other applications in the plant’s seedlings. In contrast, the absence of zinc decreases the germination rate, plant growth, chlorophyll, and protein content. This study confirms that the green synthesis of zinc oxide nanoparticles assessed from Coriandrum sativum leaves holds implication and should function as an active biofertilizer.

Five strains of Streptomyces sp. were evaluated in vitro for their ability of inhibiting the mycelial growth of Macrophomina phaseolina, the causal agent of root rot of mung bean (Vigna radiata L.). Among the Streptomyces sp. strains tested, PDK showed the maximum in vitro inhibition of mycelial growth of M. phaseolina and recorded an inhibition zone of 21 mm. The strains CBE, MDU, SA and ANR recorded inhibition zones of 18, 16, 13 and 11 mm, respectively. These Streptomyces sp. strains were tested for their growth-promoting efficiency on mung bean seedlings. Among them, CBE and PDK recorded the maximum increase in shoot length, root length and seedling vigour compared with control, followed by MDU. Three Streptomyces sp. strains (CBE, MDU and PDK) that showed higher levels of inhibition of growth of M. phaseolina in dual culture assay and plant growth-promoting activity were tested for their biocontrol activity against root rot under greenhouse and field conditions. Seed treatment or soil application with powder formulation of Streptomyces sp. strains CBE, MDU and PDK was effective in controlling root rot disease; but, combined application through seed and soil increased the efficacy in both the greenhouse and field trials. Among the treatments, seed treatment plus soil application with powder formulation of Streptomyces sp. strain CBE proved to be most effective, which reduced the root rot incidence from 26.8% (with non-bacterised seeds) to 4.0% in Trial I and from 32.0 to 4.9% in Trial II. The above treatment recorded the highest yield in both the field trials, and the yield increase was 78 and 74% over control in Trial I and Trial II, respectively. Isozyme analysis of the Streptomyces sp.-treated plants indicates that seed treatment plus soil application strongly induce the activities of peroxidase (PO-1 and PO-2) and polyphenol oxidase (PPO-2 and PPO-3) in mung bean. Among the three strains tested, Streptomyces sp. strain MDU- treated plants showed higher levels of activities of PO and PPO. Based on the above findings, it can be concluded that both the direct inhibition of pathogen and induced resistance might be involved in the control of root rot of mung bean by Streptomyces sp.

The online version contains supplementary material available at 10.1007/s11756-022-01269-3.

Piper aduncum L. (Piperaceae) has great potential for economic exploration because of the proven use of its essential oil in the agriculture and in the human health. A technique that improves its propagation, as the tissue culture, becomes necessary. Some parameters must be determined for the successful cultivation in vitro. Thus, this study aimed to determine the salts concentration of MS medium, temperature, luminosity and light quality for in vitro culture of this species. The following treatments were conducted: 1/4MS, 1/2MS, MS and 2MS; 20℃, 25℃, 30℃ and 35℃; monochromatic blue, red and white lights and the combination of red and blue, using light emitting diodes (LEDs); luminosities of 17, 37, 48 and 73 μmol·m-2·s-1 obtained with cool white fluorescent lamp. After 35 days, the treatments were analyzed. To determine the salts concentration of MS, the variables were evaluated: number of shoots, leaves and roots, length and width of leaves, length and dry mass of root and shoots and percentage of death by necrosis. To the plantlets under different temperatures, length and dry mass of shoot and root, number of shoots, number, length and width of leaves and survival and rooting percentages were measured. The plantlets that were maintained under different luminosities were evaluated for length of shoot and root, dry mass of leaf and root. To evaluate the growth under the LEDs, the length and dry mass of shoot and root, number of shoots and roots, percentage of rooting and sprouting were assessed. The medium 1/4MS and the medium 1/2MS showed better responses for number and length of root, leaf width and shoot length. The temperature 25℃ provided the highest number of leaves, length of shoot and root, root dry mass and rooting percentage. The luminosity 73 μmol·m-2·s-1 provided higher values in length of root and dry mass of leaf and root. The red LED provided plantlets with greater growth. Thus, for the in vitro cultivation of Piper aduncum, 1/4MS, environment temperature of 25℃, light intensity of 73 μmol·m-2·s-1 and environments with red light to obtain high quality plantlets for propagation of this species are recommended.