5 research outputs found

    Inoculation of zinc-solubilizing bacteria with different zinc sources and rates for improved growth and zinc uptake in rice

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    An experiment was conducted in growth chamber using sand culture technique to determine the effect of zinc-solubilizing bacteria (ZSB) inoculation with different zinc sources and zinc rates on growth and zinc uptake of rice. The treatments were consisted of non-inoculated control, two bacterial isolates (Acinetobacter sp. and Serratia sp.), two zinc sources (zinc sulfate and zinc oxide) with three rates (0, 0.2 and 0.4 mg L-1). The experiment was arranged in a factorial complete randomized (CRD) with three replications. Results revealed significant difference (p<0.05) among treatments on plant height, plant biomass, and leaf area index (LAI). The treatments also affected zinc concentration and its uptake. Plants inoculated with Acinetobacter sp. showed higher plant growth, zinc concentration and zinc uptake compared to non-inoculation and Serratia sp. Zinc sulfate at 0.2 mg L-1 was also recorded for high plant growth and zinc concentration. It can be concluded that Acinetobacter sp. and zinc sulfate at 0.2 mg L-1 have good potential in alleviating zinc deficiency in rice and important in solubilizing the insoluble zinc in soil for improved growth of rice

    Efficiency of zinc-solubilizing bacteria for in vitro zinc solubilization and its effects on IAA rice production

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    Zinc solubilizing efficiency of zinc-solubilizing bacteria (ZSB) were studied for its in vitro zinc solubilization, bacterial population, pH and IAA production. Four bacterial isolates from lowland rice soils, namely TM56 (Acinetobacter sp.), TM23 (Serratia sp.), TM9 (Serratia sp.) and BM13 (Serratia sp.) were found to solubilize different forms of insoluble zinc. TM56 was found to be significantly better for zinc carbonate and zinc oxide solubilization, followed by TM23 for zinc phosphate. The highest pH decreased occurred in zinc oxide and zinc phosphate, while zinc carbonate was lowest. Growth of bacteria was also significantly affected by different insoluble zinc in the modified liquid salts medium. Under gnotobiotic condition, TM56 showed the highest IAA production with the presence of zinc source

    Tripartite introductions of PGPR, humic acid, and N-fertilizer improve the growth and yield of sweet potato under glasshouse conditions

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    This study was undertaken to investigate the effects of plant growth-promoting rhizobacteria (PGPR) with humic acid (HA) as amendments on the morphological and physiological growth characteristics and yield of Sepang Oren sweet potato (Ipomoea batatas [L.] Lam). The experiment was conducted under glasshouse conditions at the Faculty of Agriculture, Universiti Putra Malaysia, for 110 days. Two factors were used in this experiment: The first factor was PGPR-HA inoculations (UPMB10, UPMRB9, and mixed strains) and non-inoculation-HA, and the second factor was the Nitrogen fertilizer levels (50, 75, and 100%). The treatments were replicated three times and arranged factorially in a randomized complete block design. The results showed that inoculations with PGPRs-HA (UPMRB9 and UPMB10 strains) positively affect the plant growth significantly (SPAD measurements, number of leaves, vine length, root length, leaf area index, root dry weight, shoot dry weight, and root: shoot ratio) of sweet potato upon addition of 50% and 75% of N-fertilizer, respectively. The nutrient content of soil and plant leaf significantly increased by 12-15% and 14-18%, respectively, compared to the uninoculated, when applied with the same inoculation. After 30 days, the population of soil bacteria increased, reaching a value of 8.65 log10 CFU/g soil. The use of PGPR-HA inoculations with N-fertilization resulted in a considerable rise in the majority of plant and soil parameters compared to the treatments without PGPR inoculation. Therefore, PGPR supplemented with humic acid (HA) may be considered a viable and sustainable strategy for enhancing sweet potatoes’ morphological and physiological attributes. This technique can result in increased crop productivity and serve as a substitute for nitrogen-based fertilizers

    Isolation, Characterization, and Identification of Zinc-Solubilizing Bacteria (ZSB) from Wetland Rice Fields in Peninsular Malaysia

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    Micronutrients, such as zinc (Zn), are essential for the growth and development of a wide range of crops. To overcome Zn deficiency in the soil, Zn-solubilizing bacteria (ZSB) have recently been employed. In the present study, samples from the rice fields in the state of Selangor, Malaysia, were collected to isolate, characterize, and identify the ZSB. A total of 88 strains were isolated, and only 9 strains were able to solubilize the insoluble Zn on zinc oxide (ZnO)-, zinc carbonate (ZnCO3)-, and zinc phosphate (Zn3(PO4)2)-amended Tris-minimal media agar and broth assays. The highest Zn solubilization (20.99%) was measured for the TM23 isolate when exposed to Zn3(PO4)2-modified media culture, whereas ZnCO3 showed the lowest (3.35%) Zn solubilization by ZSB. In addition, nine isolated ZSB also exhibited plant-growth-promoting (PGP) traits, including nitrogen fixation ability, siderophore production, indole acetic acid production (35.28&ndash;65.48 mL&minus;1), phosphate solubilization (27.69&ndash;77.38%), enzyme hydrolysis, and production of organic acids. Most of the isolated strains (88) were Gram-negative, except for TM54, which was Gram-positive. The four potential ZSB isolates based on 16RS rDNA sequence analysis were identified as Serratia sp. and Acinetobacter sp. Hence, this study&rsquo;s findings suggest that these isolates could be prospective candidates to overcome Zn deficiencies and reduce the consumption of chemical fertilizers in agricultural areas

    Human health risk assessment of nitrate in private well waters of shallow quaternary alluvial aquifer

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    Excessive nitrate intake via ingestion pathway and dermal absorption exposures has adverse health impacts on human health. This study evalu- ated groundwater (GW) nitrate concentrations and health risks which focused on ingestion and dermal exposures to residents in Bachok District, Kelantan, Malaysia. Three hundred (300) samples of private wells were collected and it is found that the nitrate concentrations ranging between 0.11 and 64.01 mg/Land females had HQ values more than 1, respectively. It was also observed that the mean of HQderm was lesser than HQoral for males and females. The spatial distribution of HQ by interpolation method showed high nitrate concentrations (>10 mg/L NO3-N) were distributed from the centre to the southern part of the study location, which identified as an agricultural area, indicating the used of nitrogenous fertilizers as the main source of GW nitrate contamination in this area. The findings of this study are valuable for estab- lishing private well water protection measures to stop further deterioration of GW quality caused by nitrate
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