scholarly journals Use Of Plant Growth-Promoting Bacteria And Humic Acids For Phytostabilization of Acid-Generating Mining Wastes

Author(s):  
Svetlana Bratkova ◽  
Katerina Nikolova ◽  
Petya Genova ◽  
Anatoliy Angelov

Abstract Generation of acidic mine drainage is a major environmental problem in areas with mining waste. The cost-effective method for reclaiming of acid-generating mining wastes is a vegetation cover. Using plant growth-promoting bacteria (PGPR) and humic acid in remediation have several beneficial effects. The application of both humic substances and PGPR resulted in a decrease in Cu, Fe, Zn and sulfate concentrations in a variety of drainage water samples. Both PGPR and humic acid improve plant growth when used separately, however, the combination of both treatments has the most positive effect on fresh biomass yield – between 22% and 43 % and dry biomass of plants – between 31% and 41 %. Furthermore, addition of Bacillus and Pseudomonas bacteria, in combination with humic acids, to poor soil for reclamation improved grass mineral nutrition and reduced Cu and Zn uptake. The treatment with PGPR and humic acids significantly increased the uptake of nitrogen, phosphorus and potassium by plants.

2021 ◽  
Vol 3 ◽  
Author(s):  
Subhrangshu Mandal ◽  
Kunal Kumar Saha ◽  
Narayan Chandra Mandal

Over the past few decades, the massive increase in anthropogenic activity and industrialization processes has increased new pollutants in the environment. The effects of such toxic components (heavy metals, pesticides, etc.) in our ecosystem vary significantly and are of significant public health and economic concern. Because of this, environmental consciousness is increasing amongst consumers and industrialists, and legal constraints on emissions are becoming progressively stricter; for the ultimate aim is to achieve cost-effective emission control. Fortunately, certain taxonomically and phylogenetically diverse microorganisms (e.g., sulfur oxidizing/reducing bacteria) are endowed with the capability to remediate such undesired components from diverse habitats and have diverse plant-growth-promoting abilities (auxin and siderophore production, phosphate solubilization, etc.). However, the quirk of fate for pollutant and plant-growth-promoting microbiome research is that, even with an early start, genetic knowledge on these systems is still considered to be in its infancy due to the unavailability of in-depth functional genomics and population dynamics data from various ecosystems. This knowledge gap can be breached if we have adequate information concerning their genetic make-up, so that we can use them in a targeted manner or with considerable operational flexibility in the agricultural sector. Amended understanding regarding the genetic basis of potential microbes involved in such processes has led to the establishment of novel or advanced bioremediation technologies (such as the detoxification efficiency of heavy metals), which will further our understanding of the genomic/genetic landscape in these potential organisms. Our review aimed to unravel the hidden genomic basis and eco-physiological properties of such potent bacteria and their interaction with plants from various ecosystems.


2018 ◽  
Vol 39 (3) ◽  
pp. 1365
Author(s):  
Hend Pereira de Oliveira ◽  
Raphael Oliveira de Melo ◽  
Marihus Altoé Baldotto ◽  
Messias Antônio Andrade ◽  
Lílian Estrela Borges Baldotto

Sugarcane cultivation using pre-sprouted seedlings has decreased the number of stalks used per hectare, increased the multiplication rate, improved seedling health, and increased planting uniformity. However, because this system has been only recently proposed, the number of studies evaluating this new technology is still scarce, particularly those examining the effect of the application of growth-promoting substances on seedling characteristics during the production phase. Here, we hypothesized that it is possible to combine the plant growth-promoting activity of humic acid (HA) with the inoculation of selected strains of plant growth-promoting bacteria (PGPB) to improve the yield of sugarcane seedlings compared with the individual application of these two techniques. The potential of the combined use of HA and PGPB as agricultural inputs was evaluated by conducting an experiment with sugarcane micro cuttings in a greenhouse. Treatments included control, PGPB, HA, and PGPB with HA. At the end of the experiment (60 d after planting), the plants were subjected to biometric evaluation. The results indicated that it was possible to combine HA with selected strains of PGPB (Burkholderia sp.) to improve the yield of seedlings compared with individual HA and PGPB treatments. HA, PGPB, and HA + PGPB increased the total dry matter compared with the control by 23%, 25%, and 36%, respectively. Therefore, the use of HA-based plant regulators in combination with PGPB was more effective than the isolated use of these inputs for the treatment of micro cuttings and improvement of sugarcane seedling yield.


Author(s):  
Aminthia Pombo Sudré da Silva ◽  
Fábio Lopes Olivares ◽  
Cláudia Pombo Sudré ◽  
Lázaro Eustáquio Pereira Peres ◽  
Natália Aguiar Canellas ◽  
...  

Abstract Background The bacterial-spot disease caused by different Xanthomonas species is one of the major tomato diseases that reduce crop production and quality. Pesticides indiscriminate usage has resulted in an increase in resistant bacterial strains as well as contamination of farmers, consumers and the environment. Plant growth-promoting bacteria and humic acids can act as elicitors of plant defence mechanism causing extensive transcriptional and metabolic reprogramming which, in turn, produce a range of plant chemical defences. The purpose of this study was to study how humic acids and plant growth-promoting bacteria, when applied to the substrate, affected the severity of bacterial spot symptoms in tomato leaves. Materials and methods One-month-old Micro-Tom tomato (Solanum lycopersicum L.) were transferred to 3 L pots filled with a sterile mixture of sand and vermiculite (2:1, v:v) and treated or not (control) with 250 mL of 4.5 mmol C. L−1 of humic acids, Herbaspirillum seropedicae (108 CFU. mL−1) and the combination of humic acids plus H. seropedicae. One day after substrate treatment, the leaves were inoculated (or not) with X. euvesicatoria (Xe). The area below the disease progression curve based on severity scores and the number of symptomatic leaflets was used to assess phytopathogen virulence. The concentration of oxalic, citric and succinic acids in leaf extracts were determined using HPLC analysis. Results Sole or combined H. seropedicae (BAC) and humic acids (HA) application promoted shoot and root growth related to control when plants were challenged with Xe pathogen. For plants inoculated with Xe, more significant plant-growth promotion results were obtained for HA + BAC treatment. The first visible symptoms were observed 16 days after inoculation with 2 × 104 CFU. g−1 of Xe cells in leaves of control plants. HA and BAC applied alone or combined reduced disease severity. Only plants treated with HA were able to reduce disease incidence (number of the leaflets with symptoms). Organic acids, such as oxalic, citric and succinic acids, rose in Xe-inoculated leaves. The reduced amount of organic acids in diseased leaves treated with HA + BAC may be linked to a decrease in disease progression. Conclusion Humic acids and H. seropedicae increased growth by modulating the content of organic acids in leaf tissue, attenuating the symptoms of the bacterial spot disease. Graphic abstract


Revista CERES ◽  
2018 ◽  
Vol 65 (3) ◽  
pp. 271-277 ◽  
Author(s):  
Raphael Oliveira de Melo ◽  
Hend Pereira de Oliveira ◽  
Klever Cristiano Silveira ◽  
Lílian Estrela Borges Baldotto ◽  
Marihus Altoé Baldotto

ABSTRACT Seed treatment with inoculants based on plant growth-promoting bacteria (PGPB) or the application of humic acids (HA) may increase the productivity of plants of agricultural interest. The hypothesis of this work is that it is possible to combine the effect of plant growth promoting characteristic of HA with the inoculation of PGPB selected strains in the treatment of maize seeds. Thus, providing superior responses than in single applications of both in the initial maize development. To meet this purpose, we conducted isolated application of HA or PGPB inoculation of Burkholderia gladioli and Rhizobium cellulosilyticum, and the combined application of PGPB and HA for treatment of maize seeds. At the end of the experiment (45 days after germination), the plants were evaluated biometrically, nutritionally and a bacteria count was performed in plants using the Most Probable Number technique. The results showed that it is possible to combine the effects of HA with the inoculation of selected strains of PGPB, obtaining superior responses to the isolated application of both. Thus, the use of HA-based bio-stimulants in combination with PGPB is positive and complementary compared to inputs generally used in the treatment of maize seeds.


Author(s):  
J. Monk ◽  
E. Gerard ◽  
S. Young ◽  
K. Widdup ◽  
M. O'Callaghan

Tall fescue (Festuca arundinacea) is a useful alternative to ryegrass in New Zealand pasture but it is slow to establish. Naturally occurring beneficial bacteria in the rhizosphere can improve plant growth and health through a variety of direct and indirect mechanisms. Keywords: rhizosphere, endorhiza, auxin, siderophore, P-solubilisation


2020 ◽  
Vol 53 (2) ◽  
Author(s):  
Muhammad Mubeen ◽  
Asghari Bano ◽  
Barkat Ali ◽  
Zia Ul Islam ◽  
Ashfaq Ahmad ◽  
...  

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