Dry Weight Content Research Articles

Optimization of cultural conditions for omega 3-6 fatty acids and carotenoids production by \(\textit{ Schizochytrium mangrovei}\) TB17

Heterotrophic marine microalgae Thraustochytrids are commonly found in marine environments, sediments, and decaying mangrove leaves. Their ability to produce high-value products such as docosahexaenoic fatty acids (DHA, C22:6 ω-3), carotenoids, and sterols has gained increasing attention. The products are widely applied in the food, pharmaceutical, and cosmetic industries. In this paper, results on the effect of culture medium on fatty acid composition and pigment content as carotenoid and astaxanthin of Schizochytrium mangrovei TB17 strain biomass were presented. The optimal growth conditions of strain TB17 in the flask were determined including the temperature of 28 oC, the salt concentration of 15‰, glucose as carbon source with the concentration of 3%, yeast extract as nitrogen source with the concentration of 1%. Dry cell weight (DCW) and lipid content of strain TB17 reached highest values of 12.61 ± 0.16 g/L; 34.17 ± 1.92% DCW, respectively, after 120 hours of culture. The content of DHA, docosapentaenoic acid (DPA, C22:5 ω-3) and eicosapentaenoic acid (EPA, C20:5 ω-3) in biomass accounted for 36.66 ± 1.63%; 11.73 ± 1.14% and 0.48 ± 0.01% of total fatty acid (TFA), respectively. The content of total carotenoid and astaxanthin reached 35.86 ± 1.52 µg/g and 7.18 ± 0.21 µg/g DCW after 120 hours of culture. Therefore, the obtained biomass of strain TB17 was sufficient to meet the demand for the production of DHA, DPA, EPA fatty acids as well as the extraction of carotenoids, especially astaxanthin for functional food and other biotechnological applications.

Study of Antibacterial Activity of Root Bark, Leaves, and Pericarp Extracts of Diploknema butyracea and Evaluation of Prospective Antioxidant Activity.

This study was aimed to determine the antibacterial activity of root bark, leaves, and pericarp extract of Diploknema butyracea and to evaluate the prospective antioxidant activity, total flavonoid, polyphenol, and carbohydrate content. The plant parts were collected and extracted by cold maceration, using hexane, ethyl acetate, methanol, and distilled water. Phytochemical screening of different samples of D. butyracea in different solvents revealed the presence of varied extent of alkaloid, saponin, terpenoid, anthraquinones, tannin, cardiac glycoside, flavonoid, carbohydrate, polyphenol, protein and amino acid, resin, and phytosterol. Our study showed that methanolic root bark extract exhibited the potent antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumonia with an average zone of inhibition of 17.33 mm, 14.33 mm, and 13.0 mm, respectively. Surprisingly, all of the extracts were insensitive to Escherichia coli. The lowest minimum bactericidal concentration (MBC), 4.6 mg/ml, was observed with the aqueous pericarp extract against S. epidermidis and the highest was of 50 mg/ml shown by ethyl acetate pericarp against K. pneumonia. Our results showed that both the polar and nonpolar components present in the different parts of D. butyracea exhibit prominent antibacterial activities against different bacterial strains. The in vitro 2,2′-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity showed that the methanol extract of root barks displayed the most potent antioxidant activity (IC50 : 6.1 µg/ml). The total polyphenol content of the plant part extracts was observed between 19.48 ± 0.23 and 123.48 ± 1.84 µg gallic acid equivalent/mg of dry extract weight. Likewise, flavonoid content ranged from 40.63 ± 1.28 µg to 889.72 ± 3.40 μg quercetin equivalent/mg of dry extract weight and total carbohydrate content ranged from 11.92 ± 0.60 µg to 174.72 ± 0.60 µg glucose equivalent per/mg dry extract weight. Overall, our study showed that the root bark, pericarp, and leaves extract of D. butyracea evinced prominent antibacterial properties against various pathogenic bacterial strains.

Soilless Tomato Production: Effects of Hemp Fiber and Rock Wool Growing Media on Yield, Secondary Metabolites, Substrate Characteristics and Greenhouse Gas Emissions

Replacement of rock wool by organic substrates is considered to reduce the environmental impact, e.g., through energy savings during production and waste prevention, caused by hydroponically produced crops. A suitable substrate for plant production is characterized by an optimal composition of air- and water-filled pores. In our study, we used hemp fibers as an organic alternative to rock wool in order to cultivate tomato plants in hydroponics for 36 weeks. The leaf area, plant length, and yields, as well as the quality of fruits including soluble solid contents, dry weight content, mineral composition, and contents of phenolic compounds caused by both substrates, were similar. Carotenoids were significantly increased in fruits from plants grown in hemp at some measuring dates. Nevertheless, higher emission rates of greenhouse gases such as N2O, CO2, and CH4 caused by hemp fiber compared to those emitted by rock wool during use are rather disadvantageous for the environment. While hemp proved to be a suitable substrate in terms of some physical properties (total pore volume, bulk density), a lower volume of air and easily available water as well as very rapid microbial decomposition and the associated high nitrogen immobilization must be considered as disadvantages.

Effect of spraying humic acid and potassium fertilization on growth and yield of lettuce plant Lsuctuca Sativa L

A field experiment was conducted in season 2019-2020 to study the effect of different levels fertilization using humic acid and potassium on the growth of lettuce plant. The experiment was conducted according to Complete Randomized Blocks Design(RCBD) and with two factors: the first is the ground fertilization factor using compound fertilization with levels of 200, 100 and 50 kg /ha and the second factor is foliar fertilization with humic acid with three concentrations (50, 25 and 12.5 ppm). The results showed increased in root length, wet, dry weight and chlorophyll content with higher values reached (16.1 and 16.7 / g), (97.7 and 101.1 / cm) ,(11.9 and 10.6 / g) and (76.52 and 70) using treatment 200 kg / ha potassium and 50 ppm humic acid respectively. While the lowest rates were recorded with control treatment for all treatment. Vegetative characteristics recorded same response for fertilization with level of 200 kg / ha and 50 ppm, the highest averages for stem length, leaf area, head diameter, head weight and head diameter with values (44.5 and 47.7), (8114 and 7255), (72.4 and 67.5), (1123 and 3.781) and (4.72 and 5.67) / cm

Evaluation of 11 potential trap crops for root-knot nematode (RKN) control under glasshouse conditions

Abstract A preliminary study of the development and growth of lettuce crops trap cropped with 11 trap crops for root-knot nematode (RKN) control was studied under glasshouse conditions in Kadoorie Agriculture Research Centre in Palestine Technical University. Main crop growth parameters were evaluated by measuring the shoot height, lateral root length, wet and dry weight, ash percentage, and chlorophyll content. The total RKNs recovered from both main and trap crops from root systems were counted 6 weeks post RKN artificial inoculation. The first screening of the potential trap crops against RKNs showed a significant reduction in nematode numbers in lettuce and the average number of galls per gram fresh root when trap cropped with canola, B.G. pumpkin, mustard, and vetch cv. 976. No eggs were found by the end of the experiment. These trap crops attracted more nematodes and kept them from infecting the main crop. The effect of these trap crops on the growth and development of the main crop was variable. Trap cropping lettuce with canola, mustard, Armenian cucumber, and bottle gourd pumpkin caused a significant reduction of the total wet weight and dry weight compared with the control. Still, trap cropping did not significantly affect the lateral root length and wet weight. Removing the trap crops from the field after 6–8 weeks could be applied to reduce the competition between the main crop and the trap crops.

Cerium Oxide Salicylic Acid Nanoparticles’ (CeO2: SA-NPs) Foliar Application and In-Soil Animal Manure Use Influence the Growth and Physiological Responses of Aloe vera L.

Aloe vera is an economic crop due to the presence of a gel-like substance inside the leaves, which contains polysaccharides, vitamins, proteins, fats, and amino acids. There is an ongoing need for this plant and its products for diverse food and pharmaceutical industries. To meet good agricultural practices, we studied the effect of manure application (0%, 10%, and 20% of v/v of soil) and foliar application with distilled water, salicylic acid (SA, 13.8 mg L−1 equivalent to 100 µM), cerium oxide nanoparticles (CeO2-NPs, 50 mg L−1), and cerium oxide salicylic acid nanoparticles (CeO2: SA-NPs; 100 µM + 50 mg L−1) on the growth and physiological responses of Aloe vera, and a factorial experiment was arranged based on a completely randomized design with three replications at Azarbaijan Shahid Madani University, Iran. The results showed that foliar application of CeO2: SA-NPs with the soil-based application of 10% and 20% manure increased plant dry weight and aloin content. The highest harvest index, economic yield, shoots-to-roots ratio, gel dry weight, chlorophyll a and b content, phenolics content of gel, and leaf and gel flavonoids’ content, as well as potassium, magnesium, zinc, and iron content, were obtained by the CeO2: SA-NPs × 20% manure treatment combination. The 10% and 20% manure and foliar application with CeO2-NPs, SA, and CeO2: SA-NPs increased the phenolics content of leaves compared to the control. Manure application (20%) positively affected the plant’s phosphorus content. The results revealed that co-application of soil-based cow manure and foliar CeO2: SA-NPs stimulated the growth and physiological responses of Aloe vera, and the results would be helpful to the agricultural extension sections and pioneer farmers.

Cell Retention as a Viable Strategy for PHA Production from Diluted VFAs with Bacillus megaterium

The production of biodegradable and biocompatible materials such as polyhydroxyalkanoates (PHAs) from waste-derived volatile fatty acids (VFAs) is a promising approach towards implementing a circular bioeconomy. However, VFA solutions obtained via acidification of organic wastes are usually too diluted for direct use in standard batch or fed-batch processes. To overcome these constraints, this study introduces a cell recycle fed-batch system using Bacillus megaterium uyuni S29 for poly(3-hydroxybutyrate) (P3HB) production from acetic acid. The concentrations of dry cell weight (DCW), P3HB, acetate, as well as nitrogen as the limiting substrate component, were monitored during the process. The produced polymer was characterized in terms of molecular weight and thermal properties after extraction with hypochlorite. The results show that an indirect pH-stat feeding regime successfully kept the strain fed without prompting inhibition, resulting in a dry cell weight concentration of up to 19.05 g/L containing 70.21% PHA. After appropriate adaptations the presented process could contribute to an efficient and sustainable production of biopolymers.

Melatonin application on phytochemical compositions of Agastache foeniculum under water-deficit stress

Background: Agastache foeniculum is one of the perennial aromatic plants of the Lamiaceae family. The essential oil (EO) of this plant has potent antibacterial and antifungal properties, and hence it is extensively used in the pharmaceutical and food industries. Water-deficit stress occurring at any plant growth stage changes the morphological, phytochemical, and physiological processes. Melatonin is considered as a new kind of plant growth regulator which increases plant tolerance to environmental stresses.
 Hypotheses: The response to water deficit in A. foeniculum is Mel-dependent and affects their physiological and phytochemical characteristics
 Studied species: Agastache foeniculum 
 Study site and dates: Tabriz, Iran, 2019.
 Methods: For this purpose, plants were subjected to water-deficit stress, which was followed by foliar application of melatonin as biostimulants on dry matter and secondary metabolites of A. foeniculum .
 Results: Results indicated that water-deficit stress (at 60 % of Field capacity) increased shoot dry weight, total phenol, anthocyanins and flavonoids content as well as EO content. Application of various melatonin concentrations improved the content of the mentioned traits. According to GC-MS analysis, ten chemical compounds were recognized in the EO composition of A. foeniculum . The most important EO compound (%) in the studied treatments was methyl chavicol, under severe water-deficit stress conditions with Mel at concentration of 100 μM.
 Conclusions: The results indicated that the application of Mel (at 100 µM) as a bio-inducer can alleviate the detrimental effects of water-deficit stress (at 60 and 30 % field capacity) and improve the quality of EO.

Nitrogen application affects maize grain filling by regulating grain water relations

Grain water relations play an important role in grain filling in maize. The study aimed to gain a clear understanding of the changes in grain dry weight and water relations in maize grains by using hybrids with contrasting nitrogen efficiencies under differing nitrogen levels. The objectives were: 1) to understand the changes in dry matter and percent moisture content (MC) during grain development in response to different nitrogen application rates and 2) to determine whether nitrogen application affects grain filling by regulating grain water relations. Two maize hybrids, high N-efficient Zhenghong 311 (ZH311) and low N-efficient Xianyu 508 (XY508), were grown in the field under four levels of N fertilizer: 0, 150, 300, and 450 kg N ha–1 during three growing seasons. Dry weight, percent MC and water content (WC) of basal–middle and apical grains were investigated. The difference in the maximum WC and filling duration of basal–middle and apical grains in maize ears resulted in a significant difference in final grain weight. Grain position markedly influenced grain drying down; specifically, the drying down rate of apical grains was faster than that of basal–middle grains. Genotype and grain position both influenced the impact of nitrogen application rate on grain filling and drying down. Nitrogen rate determined the maximum grain WC and percent MC loss rate in the middle and the late grain-filling stages, thus affecting final grain weight. The use of high N-efficient hybrids, combined with the reduction of nitrogen application rate, can coordinate basal–middle and apical grain drying down to ensure yield. This management strategy could lead to a win–win situation in which the maximum maize yield, efficient mechanical harvest and environmental safety are all achieved.

Isolation and molecular characterization of domestic Bradyrhizobium species from soybean roots in the savannah soil of Nigeria

Abstract. The identification of effective indigenous strains of Bradyrhizobia could lead to the development of efficient and affordable inoculants for improving soil fertility. This can also promote nitrogen fixation in smallholder farming systems of Nigeria and as well make the use of nitrogen fertilizers unnecessary. This study was conducted to characterize and evaluate the nodulating properties of indigenous Bradyrhizobium species in soybean plant. A total of 18 strains were isolated using Bradyrhizobium japonicum selective medium (BJSM) from the root nodules of plants harvested from five sites on Ahmadu Bello University farm, Zaria Kaduna State, Nigeria. These isolates were evaluated for nodulating potential in a screen house using soybean (TGx 1448-2E) as a test crop. The total number of nodules, percentage effective nodules, nodule fresh and dry weights, shoot fresh and dry weight and plant nitrogen content were assessed. The nodules produced by the isolates showed high percentage effectiveness with isolate A4 having significantly higher nodule dry weight (78.00 mg) than the rest of the test isolates. The soybean inoculant, BIOFIX used in this study performed poorly having a nodule dry weight of 6.0 mg. There was positive and highly significant correlation between the nodule dry weight, shoot dry weight and plant nitrogen content (r=0.740, 0.641, 0.616, respectively) at p<0.001. Sequence analyses were carried out on the high performing isolates from each site of sampling and the result obtained using the NCBI Database showed similarity of these isolates with reference strains belonging to the genus Bradyrhizobium (A4- Bradyrhizobium japonicum RV9, B2- Bradyrhizobium guangdongense CCBAU 51649, C1- Bradyrhizobium sp. UFLA05-149, D3- Bradyrhizobium sp. B918 and E3- Bradyrhizobium sp.UFLA05-149). A 16srRNA phylogenetic tree constructed with the sequences obtained grouped the isolates without any close reference strain. However, isolate B2 showed close affiliation with Bradyrhizobium guagdongense with 95% sequence identity. Based on the effectiveness of these five strains of Bradyrhizobium, it is suggested that they can be used as potential candidate for inoculants production.

Characterization of polyhydroxyalkanoate production capacity, composition and weight synthesized by Burkholderia cepacia JC-1 from various carbon sources

Polyhydroxyalkanoates (PHA) are microbial polymers that have received widespread attention in recent decades as potential alternatives to some petrochemical-based plastics. However, widespread use of PHA is often impeded by its cost of production. Therefore, the search for and systematic investigation of versatile microbial PHA producers capable of using various carbon sources, even in the form of animal fats, for PHA biosynthesis is desirable. This study highlights the PHA production capacity, monomer composition and molecular weight synthesized by Burkholderia cepacia JC-1, a locally isolated strain from soil, from various carbon sources. In the category of simple sugars and plant oils, the use of glucose and palm oil at C:N ratio of 40 resulted in the highest accumulation of 52 wt% and 36 wt% poly(3-hydroxybutyrate) [P(3HB)] homopolymer and dry cell weight of 2.56 g/L and 3.17 g/L, respectively. Interestingly, B. cepacia JC-1 was able to directly utilize animal-derived lipid in the form of crude and extracted chicken fat, resulting in appreciable dry cell weight and PHA contents of up to 3.19 g/L and 47 wt% respectively, surpassing even that of palm oil in the group of triglycerides as substrates. The presence of antibiotics (streptomycin) in cultivation medium did not significantly affect cell growth and polymer production. The supply of sodium pentanoate as a co-substrate resulted in the incorporation of 3-hydroxyvalerate (3HV) monomer at fractions up to 37 mol%. The molecular weight of polymers produced from glucose, palm oil and chicken fat were in the range of 991–2118 kDa, higher than some reported studies involving native strains. The results from this study form an important basis for possible improvements in using B. cepacia JC-1 and crude chicken fats in solid form for PHA production in the future.

Endophytic fungus Bipolaris sp. CSL-1 induces salt tolerance in Glycine max.L via modulating its endogenous hormones, antioxidative system and gene expression

ABSTRACT Salinity stress is one of the most serious environmental stress that inhibits plant growth. In this study, we adopted an environment friendly technique and screened different plant growth-promoting fungi for different plant growth promoting (PGP) traits and salinity stress. Among those isolates, Bipolaris sp. CSL-1 was selected based on plant growth-promoting characteristics, such as producing indole-3-acetic acid (IAA), gibberellins (GAs), organic acids and resistance to sodium chloride (NaCl) stress. Here, we found that inoculating soybean with isolate CSL-1 significantly increased shoot and root length, shoot and root fresh and dry weight and chlorophyll content under NaCl stress (200 mM). Endogenous abscisic acid (ABA) levels were significantly decreased, whereas salicylic acid (SA) levels were increased in CSL-1-inoculated plants under NaCl stress. NaCl-treated noninoculated plants showed higher levels of antioxidants and oxidative stress such as peroxidase, polyphenol oxidase (PPO), malondialdehyde (MDA) and superoxide anion (SOA). Furthermore, CSL-1 inoculation improved soybean resistance to NaCl stress, and there was a significant decrease in GmFDL19, GmNARK, and GmSIN1 expression levels. As a result, the fungal isolate CSL-1 mitigates the effect of salt stress and enhance soybean growth and might be used as a valuable ecofriendly microorganism resource in salt-affected areas.

Morphological, physiological and biochemical responses to combined cadmium and drought stress in radish (Raphanus sativus L.)

Drought and heavy metal stress are among the most important stress factors that negatively affect plant growth. This study was carried out to determine the individual and combined effects of cadmium (Cd) and drought stress on growth (plant leaf area, stem and root diameter, shoot and root fresh weight, shoot and root dry weight), physiological [electrolyte leakage (EL), leaf relative water content (LRWC)] and biochemical [antioxidant enzyme activity, hydrogen peroxide (H2O2), malondialdehyde (MDA), proline, sucrose and mineral element content] parameters of radish. In the study, four Cd concentrations (0 mg kg−1, 100 mg kg−1, 150 mg kg−1 and 200 mg kg−1), three irrigation levels (100%, 75% and 50% of field capacity—FC) were used. Leaf area, stem and root diameter, shoot and root fresh weight, shoot and root dry weight, LRWC, chlorophyll a, chlorophyll b and total chlorophyll content decreased with increased level of drought and Cd stress, but EL has increased. The effect of water deficit on these parameters was more detrimental than heavy metal stress; however, the stress-related damage was greater under combined stress conditions. In addition, H2O2, MDA, proline and sucrose content of radish leaves increased with increased water deficit and Cd stress levels. POD, CAT and SOD enzyme activities of radish leaves under combined stresses increased more than individual stress conditions. There was a significant increase in the content of Cd in the plant leaves and roots under Cd stress compared to the control. This increase in leaves was more pronounced than roots. Although individual drought and Cd stress negatively influenced radish growth and development, the damage was greater with the simultaneous occurrence of these two stress factors.

Sustainable arabitol production by a newly isolated Debaryomyces prosopidis strain cultivated on biodiesel-derived glycerol

The purpose of this research was the bioconversion of biodiesel-derived glycerol to arabitol through the adoption of sustainable bioprocessing. Arabitol production by Debaryomyces prosopidis FMCC Y69 was significantly affected by initial glycerol concentrations. The highest arabitol concentration of 45.5 g/L was achieved in the case of 120 g/L initial glycerol combined with the highest yield (0.379 g arabitol/g initial glycerol). The yeast strain showed a non-typical oleaginous behavior with low accumulation of lipids (up to 20.9% w/w) despite nitrogen-limited condition that prevailed in the fermentation media. Endopolysaccharides (IPs) were considerably high with a yield on the produced dry cell weight (YIPs/X) (=40.9% w/w) when 85 g/L of glycerol was utilized as the starting material. The fermentation efficiency was further improved when the optimal carbon to nitrogen (C/N) ratio was applied. More specifically, arabitol production was maximized (reaching 56.5 g/L) at a C/N ratio of 158 moles/moles while yield and productivity were also enhanced with respective values of 0.48 g arabitol/g consumed glycerol and 0.112 g/L.h. The increase in C/N ratios led to a decrease in cell dry weight (DCW) concentrations, which is rationally associated with decreased nitrogen availability in the growth medium. YIPs/X values were remarkably high (23.1–26.1% w/w) at the end of each fermentation with the highest concentration in absolute values of 7.3 g/L achieved at the lowest C/N ratio employed (i.e., 79 moles/moles). This study demonstrated the efficient arabitol production along with other value-added metabolites, such as IPs and cellular lipids, implementing biotechnology and renewable resources and thus contributing to the development of circular economy technologies.

Straw checkerboard barriers improve soil restoration and mitigate the impacts of drought on Medicago scutellata L.

Straw checkerboard barriers (SCB) are widely employed for ecological restoration of habitats in the arid and semi-arid regions of the world. Through a field experimental study in 2018–2019, we evaluated the environmental effects of SCB with three treatments of border, center and outside the SCB (as the control) on several soil properties such as soil water content (SWC), soil organic carbon (SOC), total N, available P and available K. Furthermore, several key physiological traits of Medicago scutellata including plant height, leaf dry weight, chlorophyll a nd carotenoids, relative water contents, malondialdehyde and proline were measured in order assess growth performance of this plant in response to microhabitat condition provided by SCB. The results showed that SOC, total N, available P and available K significantly increased by 26%, 33%, 52% and 71% respectively, nine months after SCB establishments compared to the control. The SCB reduced water losses from the soil surface and enhance soil moisture retention and resulted in higher rates of growth, CO 2 assimilation, and improved yields. Higher amounts of SWC (18–22%), leaf dry weight (183%), chlorophyll a (96%), chlorophyll b (93%), carotenoid (65%), and relative water contents (21%), were observed for individual of M. scutellata in SCB compared to control. The results also showed that the SCB resulted in the microhabitat modification of soil condition for growth characteristics of M. scutellata , particularly for border of SCB by improving SWC, which may affect nitrogenase activity and nodulation of M. scutellata. The results indicate that the barrier could create a microhabitat with improved factors that suit it for successful establishment, plant recovery and ecological restoration of arid and semi-arid areas. • Establishment of straw checkerboard barriers enhanced water retention in depths of 5, 15 and 25 cm compare to bare soil. • Soil chemical properties were improved in straw checkerboards. • High morpho-physiologic and functional attributes of Medicago scutellata in checkerboard promise for ecological restoration.

Effects of biochar amendments on rice growth and metabolic response to salinity stress in salt-affected soils

Exploring cheaper and sustainable strategies for managing salt-affected soils remains crucial in irrigated areas. Many researchers recommended using gypsum as material for reclamation salt-affected soils, which are costly and unavailable for most farmers. In this study, we used biochar derived from the common materials found in the irrigated areas that are locally available and less utilized as a substitute for gypsum for sustainable reclamation of salt-affected soils. Salt-affected soils (saline, saline-sodic and sodic) and unaffected were collected from the Watari Irrigation project, Kano State Nigeria using farmers' perceptions about the salinity situations of the irrigation scheme and existing legacy map data. The biochar used for this study were made using the Typha grass, rice straw, and rice bran samples collected from the same area. Thirty-six (36) containers (plastic pots) with a diameter of 27.5cm and height of 45cm each were filled with eight-kilogram dried soils, including non-saline, saline, and saline-sodic. We measured plant height, and normalized difference vegetation index (NDVI) at interval of 14 days. Number of tillers per plant were also measured during tillering stage at interval of 14 days. Stover dry weight, grain dry weight, electrolytic leakage and proline contents were measured after the end of the experiment. The results revealed a high significant effect (p<0.01) of biochar amendments in remediating different forms of salt affected soils. Saline sodic soil was effectively managed when using Typha biochar with a mean value very close to non-saline soil. Rice straw and rice bran reduces the salinity levels particularly in sodic soil. Therefore, biochar from different source could be used in addressing salt-specific problems rather than using a uniform treatment.

Geotechnical Effects of Municipal Solid Waste Destruction with Different Compaction Methods


 
 
 Disposal of waste in municipal solid waste landfills is the only way of waste disposal in Serbia, with daily compaction and covering with soil material. Due to less space for the construction of new landfills, it is necessary to use their maximum capacity. Well-compacted municipal solid waste takes up less volume and enables safer storage, so it is useful to previously determine the compaction parameters in the laboratory: maximum dry unit weight (γdmax) and optimal water content (wopt). In the practice so far, the standard method has been used to obtain these parameters (Proctor compaction test) which is common in soil mechanics. However, although this methodology has been adopted, different treatments of municipal solid waste at the landfill (including pre-treatment) indicate the need to change this classical approach. Therefore, during the research, various innovative solutions are introduced, such as the change of the classic flat Proctor hammer, by adding spikes, whose function, in addition to compaction, is partial destruction and shredding of municipal waste. In this way, the operation of compactors (hedgehogs) in the field is simulated. The paper presents the behaviour of four artificially prepared samples of municipal solid waste of different composition. The samples were tested in the standard Proctor apparatus at the same compaction energy, using different hammers, a standard flat hammer, and an innovative hammer with spikes. After that, the geotechnical effects of compaction depending on the applied approach were analyzed.
 
 

The Oxygen Paradigm—Quantitative Impact of High Concentrations of Dissolved Oxygen on Kinetics and Large-Scale Production of Arthrospira platensis

The cultivation of Arthrospira platensis in tubular photobioreactors (tPBRs) presents a promising approach for the commercial production of nutraceuticals and food products as it can achieve high productivity and effective process control. In closed photobioreactors, however, high amounts of photosynthetically produced oxygen can accumulate. So far, there has been a wide range of discussion on how dissolved oxygen concentrations (DOCs) affect bioprocess kinetics, and the subject has mainly been assessed empirically. In this study, we used photorespirometry to quantify the impact of DOCs on the growth kinetics and phycocyanin content of the widely cultivated cyanobacterium A. platensis. The photorespirometric routine revealed that the illumination intensity and cell dry weight concentration are important interconnected process parameters behind the impact that DOCs have on the bioprocess kinetics. Unfavorable process conditions such as low biomass concentrations or high illumination intensities yielded significant growth inhibition and reduced the phycocyanin content of A. platensis by up to 35%. In order to predict the biomass productivity of the large-scale cultivation of A. platensis in tPBRs, a simple process model was extended to include photoautotrophic oxygen production and accumulation in the tPBR to evaluate the performance of two configurations of a 5000 L tPBR.

Environmental effect on temporal patterns in lentil seed quality development

AbstractTo maximize seed longevity, seeds should be harvested at optimal maturity, that is, when seeds have acquired maximum physiological quality before deterioration begins. The aim of this study was to map the variation in temporal patterns of lentil (Lens culinaris Medik.) seed quality development when grown across four regeneration environments, which differ in the level of temperature and humidity control throughout the growing season, at the Australian Grains Genebank. Seeds of two lentil accessions (76080 and 76072) were harvested at different stages throughout development, commencing at 21 d after 50% anthesis until a maximum of 130 d. At each harvest, physiological quality traits, including germinability (fresh and dried seeds) and seed longevity, were determined, as well as seed dry weight and moisture content. Seeds of both accessions, and in all environments, started to accumulate physiological quality early on in development but did not reach their maximum until 3–54 d after mass maturity. The temporal patterns of desiccation tolerance and storage longevity were highly influenced by the environmental conditions during the maturation drying phase, affecting both ‘when’ maximum quality was attained and for how long it was maintained, thereafter. Seeds did not show a typical developmental response, rather variation was observed in seed quality development both between and within accessions grown in the different environments. The poorest storage longevity was seen when seeds of both accessions were grown in the cooler, temperature-controlled glasshouse, and the maximum longevity was observed in the warmer, semi-protected environments of the green and the big igloo for accessions 76080 and 76072, respectively.

Mutagenic efficiency of gamma rays on in-vitro regeneration in Indian mustard (Brassica juncea)

In the study Indian mustard [Brassica juncea (L.) Czern. & Coss.] was treated with different doses (0, 2.5, 10, 20 and 100 Gy) of gamma rays (radioactive cobalt, 60Co) and the effects were investigated on callus initiation, seed germination, seedling growth, total chlorophyll, protein and proline contents of seedling leaves, which were grown from hypocotyl explant of non-irradiated and irradiated seeds. Experiment was conducted at School of Biotechnology, Gautam Buddha University during 2017–18. The results showed that irradiated seeds had increased seed germination per cent, seedling length, fresh and dry weight, total chlorophyll, protein and proline content in low dose exposure (2.5Gy). Callus cultures were established from hypocotyl explants of 15 days old seedlings obtained from irradiated and non-irradiated seeds of B. juncea on MS1 [MS+BAP (2 mg/ml) + 2,4 D (1 mg/ml)] and MS2 [MS+BAP (2 mg/ml) + 2,4 D (0.5 mg/ml)] medium. Cultured hypocotyls formed callus at their cut ends within a week and simultaneously differentiation started into nodular structures from their base. MS1 callus induction medium gave good callus induction percentage (58%) as compared to MS2. It was observed that the callus was green, compact and showed 83% induction frequency in 100Gy gamma dose in MS1, whereas in different dose treatment (2.5–20Gy), callus was white and friable. It turned light brown in 100Gy treatment in MS2 medium. Thus, results of the present study showed pre-sowing seed irradiation is an effective method of improving seed germination at the early developmental stage of the plant.