Plant Shoot Length Research Articles

Soil microbiomes from the groundnut basin of Senegal contain plant growth-promoting bacteria with potential for crop improvement in arid soils.

The principal methods to maintain soil fertility in Sahel soils are largely allowing fields to go fallow and manure addition. These methods are not currently sufficient to improve soil fertility. To promote biological amendments, we aimed to understand the plant-growth promoting traits of various soil microbial isolates. The soils collected in different areas in Senegal exhibited a similar eDNA profile of bacteria; the dominant microbes were Firmicutes, followed by Proteobacteria and Actinobacteria. Of 17 isolates identified and tested, the vast majority solubilized rock phosphate and a large number grew on culture medium containing 6% salt, but very few degraded starches or hydrolysed carboxymethyl cellulose or produced siderophores. Upon single inoculation, Peribacillus asahii RC16 and Dietzia cinnamea 55 significantly increased pearl millet growth and yield parameters. For cowpea, plant shoot length was significantly increased by Pseudarthrobacter phenanthrenivorans MKAG7 co-inoculated with Bradyrhizobium elkanii 20TpCR5, and nearly all rhizobacteria tested significantly improved cowpea dry weight and pod weight. Additionally, the double inoculation of Dietzia cinnamea 55 and MKAG7 significantly increased shoot length, dry weight, and seed head weight of pearl millet. These isolates are promising inoculants because they are ecologically-friendly, cost-effective, sustainable, and have fewer negative effects on the soil and its inhabitants.

Evidence of Cooperative Interactions between Rhizobacteria and Wood-Decaying Fungi and Their Effects on Maize Germination and Growth

Advances in soil microbial communities are driving agricultural practices towards ecological sustainability and productivity, with engineering microbial communities significantly contributing to sustainable agriculture. This study explored the combined effects of two white-rot fungi (Trametes sp. and Pleurotus sp.) and six rhizobacterial strains belonging to four genera (Acinetobacter sp., Enterobacter sp., Flavobacterium sp., and Pseudomonas sp.) on maize growth and soil enzymatic activity over a 14-day period. At the plant level, germination, fresh and dry mass of the aerial and root parts, length, and stage of development of the stem, as well as the chlorophyll content, were evaluated. Furthermore, soil dehydrogenase, acid and alkaline phosphatases, pH, and electrical conductivity were evaluated. Rot fungi induced distinct effects on maize germination, with Pleurotus sp. strongly suppressing maize germination by 40% relative to that of the control. The isolated bacterial strains, except Enterobacter sp. O8, and 8 of the 12 fungus + bacterial strain combinations induced germination rates higher than those of the control (≥40%). Combinations of Flavobacterium sp. I57 and Pseudomonas sp. O81 with the rot fungus Pleurotus sp. significantly improved plant shoot length (from 28.0 to 37.0 cm) and developmental stage (fourth leaf length increase from 10.0 to 16.8 cm), respectively, compared with the same bacteria alone or in combination with the rot fungus Trametes sp. In the soil, the presence of both fungi appeared to stabilize phosphatase activity compared to their activity when only bacteria were present, while also promoting overall dehydrogenase enzymatic activity in the soil. Integrating all parameters, Trametes sp. rot fungus + Enterobacter sp. O8 may be a potential combination to be explored in the context of agricultural production, and future studies should focus on the consistency of this combination’s performance over time and its effectiveness in the field.

Synergistic effect of biochar and plant growth promoting bacteria improve the growth and phytostabilization potential of Sorghum bicolor in Cd and Zn contaminated soils

The synergetic effect of biochar (BC) and plant growth promoting bacteria (PGPB) on phytoremediation potential of plants in heavy metal (HM) contaminated soils was not well understood. A pot experiment was carried out to evaluate the effects of banana pith derived BC (0, 2.5 and 5%, w/w) as soil amendment together with inoculation of PGPB Bacillus thuringiensis SE1C2 on the growth, physiological response and phytoremediation potential of Sorghum bicolor (L.) Moench in Cd and Zn contaminated soils. Combined treatment of BC 5% and SE1C2 increased plant shoot length, root length, fresh weight and dry weight but decreased Cd and Zn accumulation as compared to other treatments. The BC 5% treatment also increased SE1C2 colonization in rhizosphere soils and tissue interior of S. bicolor even under HM stress. In addition, the plants treated with BC 5% and SE1C2 also had increased chlorophyll, carotenoid and antioxidant enzymes while lower leaf malondialdehyde and proline contents which suggest their potential in improving HM stress tolerance in plants. Similarly, the combined BC 5% and SE1C2 treatment considerably improved enzymatic activities (acid phosphatases, alkaline phosphatases, β-glucosidase and urease) in HM contaminated soils. Thus, this study concludes that the combined treatment of Bacillus thuringiensis SE1C2 and banana pith BC could be exploited as an effective strategy for improving the plant growth and phytostabilization potential in HM contaminated soils.

Chitosan microspheres-based controlled-release nitrogen fertilizers improve the biological characteristics of Brassica rapa ssp. pekinensis and the soil

Present study investigates the impact of chitosan microspheres-based controlled-release nitrogen fertilizer (Cm-CRNFs) on biological characteristics of Brassica rapa ssp. pekinensis (Chinese cabbage) and soil. The study was carried out under various four treatments, urea (0.8033 g), blank chitosan microspheres (without urea), Cm-CRNFs (0.8033 g), and a control group (CK). The results indicated that Cm-CRNFs significantly prolonged the nitrogen release and enhanced the plant shoot length, shoot diameter, number of branches, pods, total amino acids, and vitamin C of Brassica rapa ssp. pekinensis as well as increased the soil nutrient availability. Chao index of bacterial diversity analysis showed a significant reduction of 15.89 % in Cm-CRNFs, but the Shannon index value in Cm-CRNFs was increased by 23.55 % compared to CK. Furthermore, Cm-CRNFs treatment significantly influenced genus richness level of Arthrobacter, Archangium, Bacillus, and Flavihumibacter. Moreover, relative abundance of bacteria significantly enhanced Cm-CRNFs, including Acidobacteriota, Acitinobacteriota, Cloroflexi, Cyanobacteria, and Patescibacteria. Soil enzyme activity such as: urease, acid phosphatase, and catalase enzymes in Cm-CRNFs and urea treatment significantly increased. Besides, other enzymes such as: cellulase and β-glucosidase activity decreased in the Cm-CRNFs treatment. It was concluded that Cm-CRNFs potentially prolonged discharge of micro/macronutrients and improved soil bacterial diversity, which ultimately enhanced the soil fertility and improved the soil enzyme activity.

Post Reclamation Evaluation of Residual Hydrocarbons in Crude Oil Contaminated Soil Using Gas Chromatographic Techniques and Plant Growth Indices

The present study was undertaken to evaluate the post-reclamation of crude oil-contaminated soil using gas chromatographic technique and plant growth indices. Enrichment techniques, turbidometric test, plasmid curing test, classical identification method, gas chromatographic flame ionization detection technique and plant growth indices were carried out using standard procedures. The results indicated that 22 of the isolates were observed to have high pollutant degrading potentials (A600nm > 0.3) due to their crude oil utilization ability. The results also indicated that isolates which were able to degrade crude oil belonged to genera Bacillus, Pseudomanas sp., Ochrobacterium sp. and Enterobacter sp. Moreso, the remediation percentages recorded were 98 %, 80 %, 21 % and 98 %, 78 % and 22 % for the respective crude oil pollution (3 %, 5 % and 10 %) for soil inoculated plasmid borne bacteria whereas soil inoculated with plasmid cured bacterial cultures had 65 %, 52 %, 11 % and 65 %, 50 % and 20 % degradation of the same concentration of the total petroleum hydrocarbon after 60 days for both Phaseolus vulgaris and Glycine max plant seeds, respectively. The remediation percentages in the uninoculated controls include 3 %, 5 %, 10 % and 12 %, 9 % and 5 % across the pollutions for both plant seeds. A significant (P < 0.05) increase in the growth parameters of the leguminous plants like percentage germination, mean plant shoot length, mean plant root length, plant fresh weight and number of root nodules were seen more in the soil microcosms inoculated with plasmid-borne bacteria than microcosm inoculated with culture of plasmid cured bacteria across all crude oil dilutions. Crude oil had a dose-dependent negative effect on the mean bacterial counts of each of the polluted soil containing the two different plants. Thus, the study clearly suggests that the selected hydrocarbon bacterial degraders could be effectively exploited in the remediation of crude oil-polluted sites.

Extracellular Synthesis of Fe-NPs by Bacteria/Biosurfactant, Kinetic Parameter and Reduction of Cr (VI) from Pollutant Samples

Hexavalent Cr is most toxic metal and hazardous compound worldwide. It is also considered to be cellular oxidizing pollutant causing damage, mutagenic and hematopoietic effects to living systems. Present work is focused on synthesis of zero valent iron nano particles (Fe-NPs) using Bacillus subtilis SHB 13, Achromobacter xylosoxidans SHB 204 and Surfactin and their application for Cr (VI) detoxification (100 ppm) in synthetic solutions and polluted sludge, sewage and soil samples about 90-100% reduction observed with above particles. Qualitative analysis, structural characterization of Fe-NPs, adsorption, and recovery of Cr (VI) were carried out using XRD, SEM and TEM. This work explains adsorption isotherm of Cr with iron nano particles (Fe- NPs), was best fitted with Langmuir model and it followed first order rate kinetic reaction. Microcosm studies were carried out using Fe-NPs in sludge, sewage and tannery samples and Cr (VI) was completely (100 %) removed within 72 h. In another microcosm experiment, bacteria were able to reduce (60-70 %) Cr (VI) from soils with and without moisture and glucose. In green house experiments both the bacteria were able to reduce Cr (VI) (65-90%) effectively from both polluted and non-polluted soil and there was increase in root length and shoot length of plant L. esculentum was observed and maximum plant biomass was observed with plants inoculated with SHB 204 and SHB 13.

Effect of GA3 and NAA on growth, physiological parameters, and bioactive constituents of Ammi majus L.

Coumarins, the naturally occurring benzo-α-pyrone derivatives, are important group of secondary plant-metabolites derived from phenylalanine metabolism. Two net-house experiment was carried out concurrently to examine the effects of Gibberellic acid (GA3) (Experiment 1) and naphthalene acetic acid (NAA) (Experiment 2) on growth and physiological parameters, and active constituents of Ammi majus, which is a medicinally important plant rich in coumarins and various flavonoids, alkaloids, and terpenoids. Foliar-spray treatments, consisting of increasing concentrations of GA3 (0, 50, 100, 200, and 400 mg L−1) and NAA (0, 25, 50, 100, and 200 mg L−1) were applied at 45 days after sowing. Application of both of the PGRs improved all of the parameters significantly. The best results were obtained at 100 mg L−1 of GA3 (Experiment 1) and 50 mg L−1 of NAA (Experiment 2) in terms of growth characteristics (plant height, fresh weight and dry weight), physiological parameters (photosynthetic pigments, chlorophyll fluorescence, and activities of nitrate reductase and carbonic anhydrase) and seed-quality parameters (bioactive constituents). The most effective treatments, viz. 100 mg L−1 of GA3 (Experiment 1) and 50 mg L−1 of NAA (Experiment 2), resulted in appreciable increases in seed bioactive ingredients. The primary components were Methoxsalen, 7 H-furo [3,2-g] [1] benzopyron-7-one, 4, 9 dimethoxy, and p-camphorene, according to gas liquid chromatographic analyses. In comparison to the control, foliar treatment of GA3 (100 mg L−1) considerably increased the plant's shoot length (29.54%), root length (27.58%), fresh weight (36.78%), and dry weight (41.71%). Whereas, 50 mg L−1 of NAA enhanced these growth attributes by 31.12%, 32.61%, 34.84%, and 30.32%, respectively, in comparison to the control. Foliar application of 100 mg L−1 of GA3 increased the chlorophyll fluorescence (51.8%) as well as total content of chlorophyll (39.81%), and carotenoids (47.53%), in contrast with the control. Comparing the control, 50 mg L−1 of NAA enhanced the chlorophyll fluorescence, and total content of chlorophyll and carotenoids by 42.3%, 30.92%, and 27.81%, respectively. The best foliar-application treatments of 100 mg L−1 of GA3 and 50 mg L−1 of NAA were most effective for NR activity, surpassing the control by 27.7% and 21.5%, respectively. The largest increase in leaf CA activity was observed due to 100 mg L−1 of GA3 and 50 mg L−1 of NAA, which exceeded the control by 24.6% and 19.04%, respectively.

Methylorubrum rhodesianum M520 as a biocontrol agent against Meloidogyne incognita (Tylenchida: Heteroderidae) J2s infecting cucumber roots.

Root-knot nematodes (RKNs) are plant pathogens that cause huge economic losses worldwide. The biological management of RKNs may be a sustainable alternative to chemical control methods. Here, the biocontrol potential of Methylorubrum rhodesianum M520 against the RKN Meloidogyne incognita was investigated to theoretically support its application as a biocontrol agent in field production. In-vitro assays showed 91.9% mortality of M. incognita second-stage juveniles in the presence of strain M520 and that the hatching rate of M. incognita eggs was 21.7% lower than that of eggs treated with sterile water. In pot experiments, the M520 treatment caused 70.8% reduction in root-knots and increased plant shoot length and stem and root fresh weights, compared to control plant values. In split-root experiments, cucumber roots treated with M520 showed 25.6% decrease in root gall number, compared to that in control roots. M520 has multiple mechanisms against RKNs and might be used as a biocontrol agent against M. incognita in cucumber, laying a foundation for further studying M520 biocontrol against RKNs.

Green Synthesis of Zinc Oxide Nanoparticles using Leaf Extract of Causonis trifolia (L.) and its Applications on Germination and Growth Enhancement of Mustard Seeds

The present work reported the seed germination and plant growth activity studies on mustard seeds using bio-inspired green synthesized zinc oxide nanoparticles (ZnO NPs). The ZnO NPs were synthesized via green method utilizing Causonis trifolia (L.) plant leaf extract as a capping as well as reducing agent. The synthesized zinc oxide nanoparticles (ZnO NPs) have been characterized by using powder XRD (X-ray diffraction), FTIR (Fourier transforms infrared spectroscopy), emission SEM (scanning electron microscopy) and UV-visible spectroscopy. Based on various characterizations, it was proved that the nanoparticles were hexagonal Wurtzite form with more or less spherical in shape having an average particle size of 58 nm that contains 78% of metallic zinc. Seed germination and plant growth activity studies of ZnO NPs have been performed on mustard seeds through the pot method. The result revealed a high seed germination rate (91.7%) of mustard seeds when comparing observed in control pots (62.1%). Further dose-dependent studies also performed under the same condition. The measurements of each plant shoot length and root length have performed after six days. The mustard plants root grown in pots with ZnO NPs at 1000 mg/Kg (6.9 cm) have grown 627% higher and plants in pots with ZnO NPs at 100 mg/Kg (4.8 cm) have grown 436% higher than the control pot (1.1 cm). The shoot length of the mustard plant at ZnO NPs at 1000 mg/Kg (9.8 cm) has grown 316% at 100 mg/Kg (6.7 cm) has grown 216% higher than the control pot (3.1 cm). The results indicate that the synthesized ZnO NPs could potentially be used as an enrichment fertilizer to improve agricultural output.

Studies on Vermicomposting of Sericultural Wastes: An Eco-Friendly Approach for Effective Management of Seri-Wastes

Vermicompost is one of the most essential and efficient organic manure commonly applied to the mulberry field in most the advance sericulture countries. Vermicompost is the one of the beneficial biotechnology is the bioconversion of organic waste into useful form. In the current experiment, soil treated with vermicompost of three different treatments viz., Cow dung + Seri-waste (T-1), Cow dung +Seri-waste (T-2) and Cow dung +Seri-waste + Rice straw (T-3) were recorded different parameters. After the application of different treatment of vermicompost the best recorded treatment as a T-as 6.7 pH. The moisture retention capacity was recorded as 52% in T-1 and 74% and 62% respectively in T-2 and T-3, with electric conductivity as 2-3ms/cm. The soil texture of soil treated with T-2 (Cow dung +Seri-waste) showed best input as 50% as compared to T-1 and least in T-3 as 40% and 35% respectively. Application of different treatment of vermicompost on soil recorded to be T-2 (Cow dung +Seri-waste) showed positive response and high availability of microorganisms that are beneficial for the mulberry plant. The germination percentage of seed of mulberry treated with different treatment was recorded to be highest of 90% in T-2 and root and shoot length of plant grown as 26cm and 12cm as compared to T-1 and T-3 as 19 cm and 8cm, 34cm and 10cm respectively. Similarly, the moisture percentage and moisture retention capacity of T-2 was recorded to be highest as 74.64% and 73.21% respectively. Therefore, the current experiment opens new avenues vermicompost substrate for promoting of by-product utilization seri-waste in sericulture. The resultant product could be utilized for agricultural and horticultural as well. The present results offer numerous scopes for further sustainable agriculture with special emphasis on sericulture industry.

Multi-dimensional Studies on Thermotolerant Phosphate Solubilizing Bacteria Isolated from Rock Phosphate Mines for Bioactivation of Rock Phosphate

We conducted multi-parametric studies on thermotolerant phosphate solubilizing bacteria useful in bioactivation of rock phosphate. Selected two different thermotolerant phosphate solubilizing cultures. Statistical optimization found pH, ammonium sulfate and EDTA concentration to be the significant variables for high phosphate solubilization by Bacillus sp. BISR-HY63. Alkaline phosphatase production by Brevibacillus sp. BISR-HY07 was increased from 1400 unitsL−1 to 3000 unitsL−1. Partial purification of alkaline phosphatase performed by size exclusion and anion-exchange chromatography and the enzyme purified by 76 folds. Organic compost prepared and inoculated with alkaline phosphatase producing bacterium BISR-HY07 for increasing it’s efficacy. Soluble P decreased from 9.5 mgKg−1 to 4.1 mgKg−1 and available P increased from 200 mgKg−1 to 1000 mgKg−1 after incubation of 50 days. When cultures used as bioinoculants, total P content absorbed by the plants inoculated by Brevibacillus sp. BISR-HY07 along with rock phosphate was highest and significantly higher at 9.3 gkg−1. Shoot length of plants treated by rock phosphate and Brevibacillus sp. BISR-HY07 found to be highest and significantly higher at 31.5 cm. Root length, shoot biomass and root biomass of plants treated by rock phosphate and Bacillus sp. BISR-HY63 was highest but not significantly high at 10.3 cm, 0.73 g and 0.34 g respectively.

Heavy Metal-Resistant Plant Growth-Promoting Citrobacter werkmanii Strain WWN1 and Enterobacter cloacae Strain JWM6 Enhance Wheat (Triticum aestivum L.) Growth by Modulating Physiological Attributes and Some Key Antioxidants Under Multi-Metal Stress.

Due to wastewater irrigation, heavy metal (HM) exposure of agricultural soils is a major limiting factor for crop productivity. Plant growth–promoting bacteria (PGPB) may lower the risk of HM toxicity and increase crop yield. In this context, we evaluated two HM-resistant PGPB strains, i.e., Citrobacter werkmanii strain WWN1 and Enterobacter cloacae strain JWM6 isolated from wastewater-irrigated agricultural soils, for their efficacy to mitigate HM (Cd, Ni, and Pb) stress in a pot experiment. Increasing concentrations (0, 50, 100, and 200 ppm) of each HM were used to challenge wheat plants. Heavy metal stress negatively affected wheat growth, biomass, and physiology. The plants under elevated HM concentration accumulated significantly higher amounts of heavy metals (HMs) in shoots and roots, resulting in increased oxidative stress, which was evident from increased malondialdehyde (MDA) content in roots and shoots. Moreover, alterations in antioxidants like superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) were observed in plants under HM stress. The severity of damage was more pronounced with rising HM concentration. However, inoculating wheat with Citrobacter werkmanii strain WWN1 and Enterobacter cloacae strain JWM6 (107 CFU ml–1) improved plant shoot length (11–42%), root length (19–125%), fresh weight (41–143%), dry weight (65–179%), and chlorophyll a (14%-24%) and chlorophyll b content (2–24%) under HM stress. Citrobacter werkmanii strain WWN1 and Enterobacter cloacae strain JWM6 either alone or in co-inoculation enhanced the antioxidant enzyme activity, which may lower oxidative stress in plants. However, seeds treated with the bacterial consortium showed an overall better outcome in altering oxidative stress and decreasing HM accumulation in wheat shoot and root tissues. Fourier transform infrared spectroscopy indicated the changes induced by HMs in functional groups on the biomass surface that display effective removal of HMs from aqueous medium using PGPB. Thus, the studied bacterial strains may have adequate fertilization and remediation potential for wheat cultivated in wastewater-irrigated soils. However, molecular investigation of mechanisms adopted by these bacteria to alleviate HM stress in wheat is required to be conducted.

Evaluation of Bacillus and Rhizobium Strains to Enhance the Growth of Vigna radiata (L.) under Drought Stress

In the present study, strains of Bacillus and Rhizobium were evaluated for their efficacy to produce auxin and to enhance the growth of Vigna radiata (L.) under drought stress. Colorimetric analysis indicated the production of auxin in bacterial culture supernatants in the presence of 0, 200, and 500 µg ml-1 L-tryptophan. At 500 µg ml-1 of L-tryptophan, B. subtilis Z-24, and B. simplex Z-38 produced significant levels of 41.4 and 24.8 µg ml-1 auxin, respectively. High Performance Liquid Chromatography (HPLC) also detected the auxin production by bacterial strains. In vitro rooting assay also recorded maximum increase in number of lateral roots with B. simplex Z-02, over control. For pot trials, seeds treated with single and mixed bacterial cultures were grown under 28%, 20%, and 10% field capacities (FC) of loamy soils. At 28% FC (normal water level), maximum increase of 28% dry weight was observed for R. rosettiformans Z-30; as compared to respective control. At 10% FC (highest water stress), significant increases of 87% and 70% in fresh weight and root length were recorded by B. cereus Z-59 and B. simplex Z-37, respectively. In case of mixed culture, C-3 (Z-38, Z-20, and Z- 30) and C-2 (Z-59, Z-20, and Z-23) were the most effective to enhance up to 68% dry weight and 13% shoot length of plants under drought stress (10% FC). Results showed that Bacillus and Rhizobium strains have the potential to produce auxin and improved the growth of mung beans under drought stressed conditions.

Biodegradation of PAHs by Bacillus marsiflavi, genome analysis and its plant growth promoting potential

The biodegradation of hazardous petroleum hydrocarbons has recently received a lot of attention because of its many possible applications. Bacillus marsiflavi strain was isolated from oil contaminated soil of Rawalpindi, Pakistan. Initial sequencing was done by 16s rRNA sequencing technique. Bac 144 had shown 78% emulsification index and 72% hydrophobicity content. Further, the strain displayed production of 15.5 mg/L phosphate sloubilization and 30.25 μg/ml indole acetic acid (IAA) in vitro assay. The strain showed 65% biodegradation of crude oil within 5 days by using Gas Chromatography-Mass Spectrometry (GC-MS) analysis. Whole Genome analysis of Bac 144 was performed by PacBio sequencing and results indicated that Bacillus marsiflavi Bac144 strain consisted of size of 4,417,505bp with closest neighbor Bacillus cereus ATCC 14579. The number of the coding sequence was 4662 and number of RNAs was 141. The GC content comprised 48.1%. Various genes were detected in genome responsible for hydrocarbon degradation and plant defense mechanism. The toxic effect of petroleum hydrocarbons in soil and its mitigation with Bac 144 was tested by soil experiment with three levels of oil contamination (5%, 10% and 15%). Soil enzymatic activity such as dehydrogenase and fluorescein diacetate (FDA) increased up to 49% and 40% with inoculation of Bac 144, which was considered to be correlated with hydrocarbon degradation recorded as 46%. An increase of 20%, 14% and 9% in shoot length of plant at 5%, 10% and 15% level of oil was recorded treated with Bac 144 as compared to untreated plants. A percent increase of 14.89%, 16.85%, and 13.87% in chlorophyll, carotenoid, and proline content of plant was observed by inoculation with Bac 144 under oil stress. Significant reduction of 14% and 18%, 21% was recorded in the malondialdehyde content of plant due to inoculation of Bac 144. A considerable increase of 21.33%, 19.5%, and 24.5% in super oxide dismutase, catalase, and peroxidase dismutase activity was also observed in plants inoculated with strain Bac 144. These findings suggested that Bac-144 can be considered as efficient candidate for bioremediation of hydrocarbons.

Effects of polyester microfibers (PMFs) and cadmium on lettuce (Lactuca sativa) and the rhizospheric microbial communities: A study involving physio-biochemical properties and metabolomic profiles

Microfibers (MFs) and cadmium (Cd) are widely distributed in soil ecosystems, posing a potential threat to soil biota. To explore potential risks of single MFs and in combination with Cd (co-PMFs/Cd) to soil environment, we systematically investigated the effects of PMFs and co-PMFs/Cd treatments on physio-biochemical performance and metabolomic profile of lettuce (Lactuca sativa), as well as the rhizospheric bacterial communities. Our results showed that both PMFs and co-PMFs/Cd treatments adversely disturbed the plant shoot length, photosynthetic, and chlorophyll content. Co-PMFs/Cd specifically increased the activities of antioxidant enzymes. The metabolites in lettuce leaf were significantly altered by PMFs and co-PMFs/Cd treatments. A significant reduction in the relative abundance of amino acids sugar and sugar alcohols indicated the altered nitrogen and carbohydrates related metabolic pathways. Additionally, PMFs and co-PMFs/Cd treatments altered the structure of rhizospheric bacterial communities and caused significant changes in some key beneficial/functional bacteria involved in the C, and N cycles. The present study provides a novel insight into the potential effects of PMFs on plant and rhizosphere bacterial communities and highlights that PMFs can threaten the terrestrial ecosystem and should be further explored in future research.

Determination of Effective Mutation Dose on Walnut (Juglans regia L. cv. Chandler) Budwoods

Walnut (Juglans regia L., 2n=2x=32, Juglandaceae) is a deciduous temperate fruit species with an increasing economic importance and health benefits. The effective mutation dose (EMD) was not determined for ‘Chandler’ budwoods. The objective of this study was to determine the radiosensitivity of walnut budwoods to cobalt-60 gamma ray. One-year-old budwoods of ‘Chandler’ walnut cultivar carrying 4-5 buds in 20 cm in length were irradiated with cobalt-60. The gamma irradiation and chip budding were performed three different times. The budwoods were irradiated (1) with 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 Gy gamma doses on Apr 2017, (2) with 0, 20, 25, 30, 35, 40 Gy gamma doses on Sep 2017, and (3) with only 42 Gy gamma dose on Apr 2018. Then, gamma irradiated budwoods were chip budded on seedling rootstocks. Mutation 1 Vegetation 1 (M1V1) plants were obtained. The humidity content of the budwoods was determined after gamma irradiation. The bud take ratio, shoot length, and chlorophyll density of M1V1 plants were measured. From the shoot length of the plants, EMD was calculated as 42.1 Gy after the first irradiation on Apr, 2017, and that was calculated as 20.9 Gy in the second irradiation on Sep, 2017. The main plant population was obtained by previously calculated 42.1 Gy dose in the third irradiation on Apr, 2018. The survival rates of budded plants in three irradiation experiments were 21.6%, 54.8%, and 32.0%, respectively. According to the results, the most suitable gamma ray dose is 42.1 Gy.

Comparative analysis of responses to field salinity stress in contrasting soybean accessions highlights NaCl exclusion in leaves as a key mechanism for salinity stress tolerance.

Salinity is one of the main limitations to legume productivity in many regions of the world and it is estimated that 50% of all arable land will become affected by salinity by 2050. The impact of field salinity on soybean performance was assessed using two soybean accessions (KCW and HMC) cultivated in salt-treated soil and non-salt treated soil. We used a 30 cm deep field system layered with 0.4 kg/m2 NaCl for the salt-treated experiment while the control field received no salt treatment. The results show that salinity reduces soybean growth and yield as evident from the reduction in the plant shoot length, stem diameter, number of branches, number of pods and seed weight. However, the reduction in these growth parameters was less pronounced in the HMC accession than the KCW accession. Furthermore, Na+ content in leaves of the HMC accession was lower than that of the KCW accession. This proved that salinity has a damaging effect on soybean growth and yield and the relative tolerance of the HMC accession is attributed in part to its ability to restrict Na+ transport to the leaves. While the study emphasizes salt exclusion as a potentially useful mechanism for salinity tolerance in soybean, it provides evidence that the HMC accession is a good genetic resource for breeding soybean varieties with improved salinity stress tolerance.

Effect of watering frequency on germination and early growth of maize (Zea mays) seed

Maize (Zea mays) is one of the most important cereal crops grown principally during the raining season in Ethiopia which is commonly used for both human consumption and poultry feed. Green house experiment on the effect of watering frequency on germination and early growth of maize was carried out at Ambo Agricultural Research Center using a hybrid maize variety (Jibat) (Zea mays) from December 1 to January20th, 2018/19. The study was conducted to determine the effect of watering frequencies on germination and early growth of maize seed (Zea mays). The highland maize hybrid variety of AMH-851 (Jibat) was used as a test crop for the experiment. Three watering frequencies one day interval, three days intervals and five days intervals were used as an experimental treatment, and they were laid out in a Completely Randomized Design (CRD) with four replications. The watering frequencies showed statistically significant differences, on plant shoot length and biomass weight, but the treatments didn’t reveal statistical difference on seedlings emergence. Therefore, one day watering interval shows better performance on shoot length, fresh and dry biomass.

GENETIC EVALUATION FOR MORPHOLOGICAL TRAITS OF CORIANDRUM SATIVUM GROWN UNDER SALT STRESS

The Coriandrum is most important among the herb which is used as an ingredient in daily human food. It contains a good amount of antioxidants and health improving ingredients that save human body cells from diseases. It is very sensitive for abiotic environmental stress conditions involving drought, heat, and salt stress as important stress conditions. For this purpose, a study was planned to conduct in the greenhouse of the Institute of Molecular Biology and Biotechnology, University of Lahore to determine the effects of salt stress on Coriandrum seedling growth. For our study we have selected four Coriandrum varieties viz., GAMZE, EAGLE, SUPER XO, and PAK-ORG. The results revealed that there were significant differences among the treatments of NaCl concentrations, Coriandrum genotypes, and the interactions among the Coriandrum genotypes and salt concentrations applied. The average Coriandrum seedling length was recorded as 23.021±1.2026cm while root length was recorded as 22.0128±1.0027cm. The genotype GAMZE showed higher root and shoot length which indicated that GAMZE was a higher salt-tolerant genotype and may be used as a salt-tolerant genotype to improve yield per plant in Coriandrum. The genotype EAGLE has shown poor performance for all of the studied traits which indicated that it was a salt-sensitive Coriandrum genotype. The genetic advance and heritability were found higher for all of the studied traits. The significant correlation between shoot length and root length indicated that the genotypes grow longer roots under stress conditions to increase the shoot length of plants while survive under stressful environmental conditions. The selection of Coriandrum genotype on the basis of root length and shoot length may be useful to improve slat stress tolerance in Coriandrum genotypes for higher seed and green plant biomass yield.

Nanomagnetite and Chitosan Affect Seed Germination and Growth of Wheat (Triticum Aestivum L.)

Iron deficiency is one of the limiting factors of plant growth. In recent years nanotechnology has attracted attention to producing forms of iron that are available to plants. Chitosan, which is widely used in agriculture due to its unique properties, has metal-binding abilities. We decided to study nanomagnetite and chitosan's combined action to improve seed germination and growth of wheat (Triticum aestivum L.). The thumbnail method was used in the study. The seeds were treated with magnetite suspension and chitosan solutions before planting. An increase in plant growth, root, and shoot length of plants was found in all seed treatment methods (chitosan, nanomagnetite, and combined action). This increase was significantly dependent on the concentration of chitosan. However, chitosan and magnetite combination was 1.3 times more effective for seed germination than pure chitosan or magnetite. A mechanism based on chitosan's ability to promote the better transfer of iron ions to plants is proposed. However, further investigation for the optimization of chitosan/magnetite proportions for improving seed growth is required.