Mz Alam

Antioxidant compounds and minerals in tomatoes by Trichoderma-enriched biofertilizer and their relationship with the soil environments

Abstract The experiment was conducted to evaluate the efficacy of Trichoderma-enriched biofertilizer (BioF/compost) on antioxidants and minerals in ripe tomatoes and soil health improvements in terms of nutrient availability and microbial populations. The study was comprised of six treatments: control (zero input); recommended doses of NPK (135.5, 45.6 and 22.9 kg ha−1, respectively); 100% BioF/compost; 75% BioF/compost+25% N; 50% BioF/compost+50% N; and 25% BioF/compost+75% N. The recommended doses of P and K were used in the last three treatments. It was found that the application of 100% BioF/compost enhanced plant growth, leaf greenness, and produced 12.9% higher yield compared to the recommended doses of NPK and other treatments. Mineral contents (P, K, Ca, Mg, Cu, Fe, Mn and Zn) in tomato roots, shoots and fruits and antioxidant compounds, i.e., ascorbic acid, (β-carotine, and lycopene were increased significantly in fruits fertilized with 100% BioF/compost. The high efficiency of Trichoderma compost might be the result of its potential of nutrient solubilization and harboring soil microorganisms. Collectively, BioF/compost increased soil fertility and favored growth of microbes in the rhizosphere which ultimately contributed to higher yield, antioxidant, and mineral concentrations in tomatoes. Thus, Trichoderma-enriched biofertilizer may reduce application of chemical fertilizers and therefore, can be considered as a noble practice in sustainable agriculture.

Effect of Salinity Intrusion on Food Crops, Livestock, and Fish Species at Kalapara Coastal Belt in Bangladesh

Salinity has caused significant negative effects on agricultural production. This research is focused on the vulnerabilities of soil and water salinities on crop, fish, and livestock production across the Kalapara coastal belt of Bangladesh. Several parameters were measured as indicators of salinity. The electrical conductivity of water was found to be significant with TDS, F−, Cl−, , Na

CytR Homolog of Pectobacterium carotovorum subsp. carotovorum Controls Air-Liquid Biofilm Formation by Regulating Multiple Genes Involved in Cellulose Production, c-di-GMP Signaling, Motility, and Type III Secretion System in Response to Nutritional and Environmental Signals

Pectobacterium carotovorum subsp. carotovorum [Pcc (formerly Erwinia carotovora subsp. carotovora)] PC1 causes soft-rot disease in a wide variety of plant species by secreting multiple pathogenicity-related traits. In this study, regulatory mechanism of air-liquid (AL) biofilm formation was studied using a cytR homolog gene deletion mutant (ΔcytR) of Pcc PC1. Compared to the wild type (Pcc PC1), the ΔcytR mutant produced fragile and significantly (P < 0.001) lower amounts of AL biofilm on salt-optimized broth plus 2% glycerol (SOBG), yeast peptone dextrose adenine, and also on King’s B at 27°C after 72 h incubation in static condition. The wild type also produced significantly higher quantities of AL biofilm on SOBGMg– (magnesium deprived) containing Cupper (Cu2+), Zinc (Zn2+), Manganese (Mn2+), Magnesium (Mg2+), and Calcium (Ca2+) compared to the ΔcytR mutant. Moreover, the wild type was produced higher amounts of biofilms compared to the mutant while responding to pH and osmotic stresses. The ΔfliC (encoding flagellin), flhD::Tn5 (encoding a master regulator) and ΔmotA (a membrane protein essential for flagellar rotation) mutants produced a lighter and more fragile AL biofilm on SOBG compared to their wild counterpart. All these mutants resulted in having weak bonds with the cellulose specific dye (Calcofluor) producing lower quantities of cellulose compared to the wild type. Gene expression analysis using mRNA collected from the AL biofilms showed that ΔcytR mutant significantly (P < 0.001) reduced the expressions of multiple genes responsible for cellulose production (bcsA, bcsE, and adrA), motility (flhD, fliA, fliC, and motA) and type III secretion system (hrpX, hrpL, hrpA, and hrpN) compared to the wild type. The CytR homolog was therefore, argued to be able to regulate the AL biofilm formation by controlling cellulose production, motility and T3SS in Pcc PC1. In addition, all the mutants exhibited poorer attachment to radish sprouts and AL biofilm cells of the wild type was resistant than stationary-phase and planktonic cells to acidity and oxidative stress compared to the same cells of the ΔcytR mutant. The results of this study therefore suggest that CytR homolog is a major determinant of Pcc PC1’s virulence, attachment and its survival mechanism.

Effects of Integrated Pest Management on Pest Damage and Yield Components in a Rice Agro-Ecosystem in the Barisal Region of Bangladesh

Recently, recognition of negative environmental impacts associated with overuse of pesticides in the agricultural regions of Bangladesh has made it clear that unsustainable pest-control strategies must change. Integrated Pest Management (IPM) was developed for use as a tool in the production of healthy, sustainably grown food. A strategic approach to crop-pest control, IPM aims to minimize pest populations by combining environmentally friendly pest-control methods and economically viable farming practices. This study examined the impact of IPM on insect damage to crop-yield parameters in a rice agro-ecosystem. IPM methods tested were: 1) collection of egg masses; 2) sweeping (using a funnel shaped net to capture insects); 3) perching (installing a branch or pole which serves as a resting place for predatory birds); and 4) Economic Threshold Level (ETL) based insecticide application (The ETL is the point at which the value of the crop destroyed exceeds the cost of controlling the pest). We also examined the effects of prophylactic insecticide application and current management practices on rice yield. Rice-yield indicators included number of healthy tillers, number of hills, central leaf drying (Dead Heart), and grain-less panicles (White Head). For two consecutive years, the lowest percentages of Dead Heart (1.23 and 1.55) and White Head (2.06) were found in the IPM-treated plots. Further, the IPM-treated plots had higher yields (7.3-7.5 ton/ha) compared with the non-IPM treatments (6.28-7.02 ton/ha). The location of the plots appeared to be non-significant for all measured yield components. The effect of treatment on the percentage of Dead Heart, White Head, number of hills, and yield was statistically significant (p ≤ 0.05). We concluded that IPM is an effective strategy for obtaining high rice yields in sustainable rice agro-ecosystems.

Contamination status of arsenic, lead, and cadmium of different wetland waters

The present investigation was conducted to determine the contamination status of arsenic (As), cadmium (Cd), and lead (Pb) in the wetland waters of Bhaluka in Bangladesh. Water samples were collected from 15 selected wetlands of Bhaluka region and analyzed using an atomic absorption spectrophotometer. Estimated results of three metals detected were As (7–80 µg L−1), Pb (0–86 µg L−1) and Cd (0–70 µg L−1) in water samples in all wetlands. The level of As in all investigated wetlands (93%) was higher than that of WHO recommended permissible limit of drinking water except Alanga wetland. However, As levels were higher than that recommended for livestock water quality levels. Eighty-seven percent of the investigated wetlands showed lower content of Pb than WHO recommended permissible limit of drinking water, but two wetland waters (Dohuria-1 and Chowdhuri) were polluted with higher Pb levels. Sixty-seven percent of the investigated wetlands displayed higher levels of Cd than WHO recommended permissible limit in drinking water. Dissolved organic material showed no significant difference among the 15 investigated wetlands water, but total dissolved solids was significantly greater. The condition of the water of all wetlands was basic pH. All water samples were applied to linear regression equation and correlation coefficients where values showed no significant differences. Data demonstrate that the estimated high metal concentrations of these ponds may contribute to bioaccumulation within plants, food grains and shrimp.

Air Pollutants and their Possible Health Effects at Different Locations in Dhaka City

Air pollution is a major environmental risk. For many decades, air pollutants have increased dramatically in the city of Dhaka. Study of air pollutants in Dhaka, as well as other urban areas, is significantly important for the sustainable environment. The present research is focused on air pollutants and their possible health effects in the areas of Dhaka city. Different pollutants such as, volatile organic compounds (VOC, s), carbon monoxide (CO), relative humidity (RH), nitrogen oxide (NOx), hydrogen sulfide (H2S), carbon dioxide (CO2), oxygen (O2),sulfur dioxide(SO2), particulate matter (PM10), particulate matter (PM2.5), suspended particulate matter (SPM), and lead (Pb) were found to be at hazardous levels in this study area. The VOC was found to have a statistically positive correlation with CO, RH, NOx, H2S, CO2, PM10, PM2.5, SPM, and Pb (p<0.01; 0.01<p ≤ 0.05; 0.05<p ≤ 0.1). Similarly, a positive correlation was found between each of CO2, CO, SO2, NOx, H2S, SPM, PM10, PM2.5, and Pb. These air pollutants have significantly increased from June 2016 to July 2017 at different locations in Dhaka. According to public perception and health physicians, air pollutants contribute to health concerns such as, eye irritation, headaches, damage to kidneys and central nervous system, skin cancer, cardio vascular diseases, nausea, asthma, and anemia. Regular monitoring of air quality parameters can be effective to protect inhabitants from various illnesses as well as significant help in providing a guideline for the development of a sustainable environment in the city dwellers of Dhaka.

Comparative Study of Integrated Pest Management and Farmers Practices on Sustainable Environment in the Rice Ecosystem

Integrated pest management (IPM) is an environmentally friendly technology. IPM is a multifaceted approach to pest management that seeks to minimize negative impacts on the environment. This technique is an important step towards providing healthy, viable food for a growing global population. The focus of this study was to examine the impact of integrated pest management in a rice agroecosystem. Currently, more than 80% of farmers rely on pesticides. IPM methods employed in our study had an impact on the number of healthy tillers and hills and grain weight. The lowest percentage of dead heart (1.03) and white head (2.00) was found in the IPM treated plots. These plots had an average yield of 7.4 tonne/ha. We found that there were significant differences between the treatment and the observed percentage of dead heart, grain weight, and yield. We conclude that IPM practices are an effective strategy for obtaining high rice yields while protecting the environment and creating a more sustainable agroecosystem. Furthermore, the need for ongoing research and training on IPM methods will be essential for creating a sustainable rice agroecosystem.

Metal-Adapted Bacteria Isolated From Wastewaters Produce Biofilms by Expressing Proteinaceous Curli Fimbriae and Cellulose Nanofibers

Bacterial biofilm plays a pivotal role in bioremediation of heavy metals from wastewaters. In this study, we isolated and identified different biofilm producing bacteria from wastewaters. We also characterized the biofilm matrix [i.e., extracellular polymeric substances (EPS)] produced by different bacteria. Out of 40 isolates from different wastewaters, only 11 (27.5%) isolates (static condition at 28°C) and 9 (22.5%) isolates (agitate and static conditions at 28 and 37°C) produced air–liquid (AL) and solid–air–liquid (SAL) biofilms, respectively, only on salt-optimized broth plus 2% glycerol (SOBG) but not in other media tested. Biomass biofilms and bacteria coupled with AL biofilms were significantly (P ≤ 0.001) varied in these isolates. Escherichia coli (isolate ENSD101 and ENST501), Enterobacter asburiae (ENSD102), Enterobacter ludwigii (ENSH201), Pseudomonas fluorescens (ENSH202 and ENSG304), uncultured Vitreoscilla sp. (ENSG301 and ENSG305), Acinetobacter lwoffii (ENSG302), Klebsiella pneumoniae (ENSG303), and Bacillus thuringiensis (ENSW401) were identified based on 16S rRNA gene sequencing. Scanning electron microscope (SEM) images revealed that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, A. lwoffii ENSG302, and K. pneumoniae ENSG303 are highly fibrous, compact, and nicely interlinked as compared to the biofilm developed by E. ludwigii ENSH201 and B. thuringiensis ENSW401. X-ray diffraction (XRD) results indicated that biofilm matrix produced by E. asburiae ENSD102, uncultured Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 are non-crystalline amorphous nature. Fourier transform infrared (FTIR) spectroscopy showed that proteins and polysaccharides are the main components of the biofilms. Congo red binding results suggested that all these bacteria produced proteinaceous curli fimbriae and cellulose-rich polysaccharide. Production of cellulose was also confirmed by Calcofluor binding- and spectrophotometric assays. E. asburiae ENSD102, Vitreoscilla sp. ENSG301, and A. lwoffii ENSG302 were tested for their abilities to form the biofilms exposure to 0 to 2000 mg/L of copper sulfate (for Cu), zinc sulfate (for Zn), lead nitrate (for Pb), nickel chloride (for Ni), and potassium dichromate (for Cr), several concentrations of these metals activated the biofilm formation. The polysaccharides is known to sequester the heavy metals thus, these bacteria might be applied to remove the heavy metals from wastewater.

Status of Biodiversity at Wetland Ecosystem of Mohangonj Upazila in Netrakona District

Species in wetlands provide ecosystem services, and protect the sustainable environment for human beings. The wetland biodiversity has been impacted at Mohangonj in Bangladesh due to the development of major environmental threats. The present research is undertaken to report the species status, wetland properties, and major environmental pressures in each wetland ecosystem. Among the recorded species, the total percentage of visible, threatened, endangered, and extinct species was 69.23, 18.62, 10, and 1.92% in these wetland ecosystems, respectively. The highest number of threatened species was found in the wetland of Aizda (29%); the lowest was in Khalaura (8%). The maximum number of endangered species was noted in the wetland of Sonarthal (16%), and the minimum was in Chadra (4%) wetland. Four percent species were in the extinct category at some of the wetland ecosystems. Wetland biodiversity protects wetland ecosystem services and the sustainable environment for species conservation. Continuous monitoring of wetland biodiversity might be helpful for the conservation of species in the wetland ecosystem.