Decrease In Dry Weight Research Articles

Flag Leaf of Bread Wheat (Triticum aestivum L.) Genotypes and Relation with Yield Component under Rainfed Conditions

An experiment was carried out to assess flag leaf fresh and dry weight of advanced bread wheat genotypes and their relation with yield and yield components. A total of 25 bread wheat genotypes were tested during the 2017-2018 cycles in four locations in the Trakia region, Turkey. The experiment was conducted in a randomized complete blocks design (RCBD) with four replications. Grain yield (GY), spike number per square meter (SNM), kernel number per spike (KNS), spikelet number per spike (SNS), spike weight (SW), plant height (PH), peduncle length (PL), spike length (SL), flag leaf fresh weight (FLFW), flash leaf dry weight (FLDW) were investigated. The combined ANOVA revealed significant differences among genotypes (G), environments (E) and their interaction (G×E) for grain yield (p<0.01). The highest grain yield was performed by G21 (6807 kg ha-1) and G20 (6776 kg ha-1). Both genotypes also had higher yield potential across four environments. Therefore, they were considered stable genotypes. Flag leaf fresh and dry weight in wheat genotypes positively affected spike length, spikelet number per spike, kernel number per spike and spike weight. As the plant density per unit area increased, there was a decrease in flag leaf fresh and dry weight. Increasing in the spike number per square meter negatively affected and reduced flag leaf fresh and dry weight in wheat genotypes. Results showed that spike weight, flag leaf fresh and dry weight of the wheat genotypes could be used in the selection of wheat breeding study for yield components. The longest spike, the highest number of grains per spike and the number of spikelets were determined in G17, together with the yield above the average. In addition, G17 had the highest spike weight and flag leaf fresh and dry weight. For this reason, G17 has been determined that can be used in breeding studies due to its agronomic characteristics. The results of the research showed that flag leaf dry and fresh weight could be used for yield components in wheat breeding selection under rainfed conditions.

Physiological and molecular mechanism of ginger (Zingiber officinale Roscoe) seedling response to salt stress.

We used 'Shannong No.1' experimental material to simulate higher salt concentration in ginger and analyzed the physiological responses of different parts of ginger seedlings under salt stress. The results showed that salt stress led to a significant decrease in fresh and dry weight of ginger, lipid membrane peroxidation, increased sodium ion content and enhanced activity of antioxidant enzymes. Compared with the control, the overall plant dry weight of ginger under salt stress decreased by about 60%, and the MDA content in roots, stems, leaves, and rhizomes increased by 372.27%, 184.88%, 291.5%, and 171.13%, respectively, and the APX content increased by 188.85%, 165.56%, 195.38%, and 40.08%, respectively. After analysis of the physiological indicators, it was found that the roots and leaves of ginger were the most significantly changed parts. We analyzed the transcriptional differences between ginger roots and leaves by RNA-seq and found that they jointly initiated MAPK signaling pathways in response to salt stress. By combining physiological and molecular indicators, we elucidated the response of different tissues and parts of ginger to salt stress during the seedling stage.

Evaluation of physical and mechanical properties of intact sandstones through the Analytic Hierarchy Process (AHP)

One of the most significant factors affecting the strength and deformation of intact rocks is weathering, which drastically reduces the rocks’ properties. This study used the Analytical Hierarchy Process model to assess the ranking of strength and physical nature of intact sandstone samples from various locations. The AHP analyses considered fine-grained sandstones, four evaluation criteria, and five different Malaysian locations. When the weathering grade decreases, the strength of the rock increases. Weathering causes decrease in dry unit weight and an increase in porosity. The porosity of weak rock materials influences their strength. The effect is more obvious in grade IV materials, where dry and wet conditions can significantly impair rock strength. According to the AHP analysis results, those diverse sites have distinct attributes in terms of numerous evaluation criteria, depending on the location and its geological features. Based on the general evaluation points in this study, Puncak Perdana were found to have the highest rock strength, whereas Kempas presented the lowest rock strength in general. In addition, Beris Dam, Bukit Indah to Mersing, and Desa Tebrau could be declared as second, third and fourth, respectively, in presenting the rock strength quality of various sandstones samples.

Zat12 Gene Ameliorates Temperature Stress in Wheat Transgenics by Modulating the Antioxidant Defense System

The present study was undertaken with the objective to reconnoiter the role of Zat12-related biochemical activities in temperature stress tolerance in wheat transgenic lines Z-8-12 1A, Z-8-12 1B, Z-8-19, and Z-15-10, which were produced by transforming wheat-cultivar PBW 621. Zat12 transgenics (ZT) along with non-transgenic (NT) wheat cultivars (PBW 621, PBW, 550, and HD 3086) were assessed at the three-weeks seedling stage under chilling (−2 °C and −4 °C) and heat (30 °C and 32 °C) stress. Specific activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), glutathione-S-transferase (GST), glutathione reductase (GR), and antioxidants (proline and ascorbate) were profoundly increased under temperature stress in ZT related to NT. However, under −4 °C and 32 °C, a significantly higher increase was reported. In contrast, H2O2 and MDA were found to be much lower in ZT than in NT. Similarly, lesser decreases in length, fresh weight, and dry weight of seedlings were reported in ZT at 30 °C and 32 °C. RT-PCR studies revealed the enhanced expression of Zat12 in the roots of seedlings at the 5, 10, and 14 days after germination (DAG) stages in ZT under the stress conditions. Upregulation of the antioxidant defense system in ZT and their better tolerance depict an alternative for wheat cultivation under temperature stress-prone areas.

Melatonin improves drought stress tolerance of pepper (Capsicum annuum) plants via upregulating nitrogen metabolism.

While ameliorating effects of melatonin (MT) on abiotic stress tolerance in plants are widely reported, the mechanism that underlies this process remains elusive. This work investigated mechanisms by which MT improved drought tolerance in pepper (Capsicum annuum ) plants. A foliar spray of 0.1mM MT treatment was applied to plants grown at 80% and 40% of full field capacity for 3days. Drought stress caused a significant decrease in plant dry weight, relative water content, leaf water potential, PSII efficiency (F v /F m ratio), chlorophyll, soluble protein, leaf and root nitrogen content. Drought increased hydrogen peroxide, malondialdehyde (MDA), nitrate, ammonium, free amino acids, soluble sugars, proline and glycine betaine. Drought also increased peroxidase (POD), glutathione S-transferase (GST) and catalase (CAT) activities, electrolyte leakage (EL) and methylglyoxal (MG). MT pre-treatment reduced oxidative stress and improved nitrogen metabolism by activating various enzymes such as nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), glutamate synthetase (GOGAT) and glutamine dehydrogenase (GDH) activities. It also activated enzymes related to the glyoxalase system (Gly I and Gly II) and decreased NO3 - , NH4 + and free amino acid content. Our study suggests a cost-effective and sustainable solution to improve crop productivity in water-limited conditions, by enhancing plant growth, photosynthesis and nitrogen content.

Effects of post-silking low temperature on the starch and protein metabolism, endogenous hormone contents, and quality of grains in waxy maize.

Waxy maize has many excellent characteristics in food and nonfood industries. However, post-silking low temperature (LT) has severe limitations on its grain yield and quality. In this study, field and pot trials were conducted to investigate the effects of post-silking LT on the physiological, biochemical, and functional characteristics of two waxy maize grains. The field and pot trials were performed with sowing date and artificial climate chamber, respectively, for LT treatment from silking stage to maturity. Results in pot trial were used to explain and validate the findings in field trial. Compared with the ambient treatment, the LT treatment significantly reduced kernel weight during the grain filling stage (P < 0.05). LT treatment in both environments resulted in an average decrease in dry weight of SYN5 and YN7 at maturity by 36.6% and 42.8%, respectively. Enzymatic activities related to starch and protein biosynthesis decreased under the LT treatment during the filling stage, accompanied by a decrease in the accumulation amounts and contents of soluble sugar and starch, and a decrease in protein accumulation amount. Meanwhile, the contents of abscisic acid, indole-3-acetic acid, and gibberellin 3 in grains decreased under the LT treatment during the filling stage. Peak, trough, breakdown, final, and setback viscosities of grains decreased by LT. LT treatment decreased the gelatinization enthalpy of grains and increased the retrogradation percentage. In conclusion, post-silking LT stress altered the content of grain components by inhibiting the production of phytohormones and down-regulating the enzymatic activities involved in starch and protein metabolism, which resulted in the deterioration of grain pasting and thermal properties.

Antibiotics in the Environment: Prescribing Risks to Non-Target Organisms

Background: The cephalosporins class is among the most widely used group of antimicrobials worldwide. Antibiotics, together with other drugs and personal care products, make up a group of emerging contaminants. The effects of exposure to this group of chemical contaminants on non-target organisms are not well understood, as they are still poorly studied. Therefore, this study evaluated the phytotoxicity of five cephalosporins in Lactuca sativa. Methods: Lettuce seeds were exposed to different concentrations of antibiotics (25 to 500 mg/L) for 5 days in the dark. After this period, the germination percentage and the wet and dry weights were recorded. Results: The highest tested concentration (500 mg/L) inhibited the germination of lettuce seeds (p &lt; 0.05); there was a decrease in dry weight when exposed to a first-generation cephalosporin (p &lt; 0.05). Additionally, there was a significantly negative influence (p &lt; 0.05) on the fresh weight, especially in the group that evaluated the exposure of seeds to 25 mg/L of Cefepime. Conclusions: We emphasize that there is no record of environmental concentrations of cephalosporins in soil, and therefore, we can indicate that it is possible to have environmental damage resulting from the inappropriate and constant disposal of cephalosporins in the environment.

New insights into cadmium tolerance and accumulation in tomato: Dissecting root and shoot responses using cross-genotype grafting

Cadmium (Cd) is one of the most threatening soil and water contaminants in agricultural settings. In previous studies, we observed that Cd affects the metabolism and physiology of tomato (Solanum lycopersicum) plants even after short-term exposure. The objective of this research was to use cross-genotype grafting to distinguish between root- and shoot-mediated responses of tomato genotypes with contrasting Cd tolerance at the early stages of Cd exposure. This study provides the first report of organ-specific contributions in two tomato genotypes with contrasting Cd tolerance: Solanum lycopersicum cv. Calabash Rouge and Solanum lycopersicum cv. Pusa Ruby (which have been classified and further characterized as sensitive (S) and tolerant (T) to Cd, respectively). Scion S was grafted onto rootstock S (S/S) and rootstock T (S/T), and scion T was grafted onto rootstock T (T/T) and rootstock S (T/S). A 35 μM cadmium chloride (CdCl2) treatment was used for stress induction in a hydroponic system. Both shoot and root contributions to Cd responses were observed, and they varied in a genotype- and/or organ-dependent manner for nutrient concentrations, oxidative stress parameters, antioxidant enzymes, and transporters gene expression. The findings overall provide evidence for the dominant role of the tolerant rootstock system in conferring reduced Cd uptake and accumulation. The lowest leaf Cd concentrations were observed in T/T (215.11 μg g−1 DW) and S/T (235.61 μg g−1 DW). Cadmium-induced decreases in leaf dry weight were observed only in T/S (−8.20%) and S/S (−13.89%), which also were the only graft combinations that showed decreases in chlorophyll content (−3.93% in T/S and −4.05% in S/S). Furthermore, the results show that reciprocal grafting is a fruitful approach for gaining insights into the organ-specific modulation of Cd tolerance and accumulation during the early stages of Cd exposure.

Effects of strontium on the morphological and photosynthetic physiological characteristics of Vicia faba seedlings

The adaptation of plants to strontium (Sr) stress requires a more systematic understanding. In the present study, the morphological and photosynthetic physiological characteristics of Vicia faba seedlings under Sr stress (88Sr, 0–1,000 mg·L−1) were analyzed in solution culture. The results showed that Sr treatment decreased the biomass and root activity of V. faba seedlings significantly, but fortunately, there was almost no root necrosis. In plant morphology, the taproot length, lateral root number, plant height, branching number and internodes number of V. faba were significantly inhibited, thus the apical dominance of taproot and terminal bud was more obvious. The accumulation of Sr resulted in the decrease of leaf area, dry weight, stomatal density and stomatal aperture, while the guard cell length increased, and the specific leaf weight (SLW) increased first and then decreased. These changes in stomatal morphology may be a positive regulation to reduce water loss. In addition, V. faba increased the non-photochemical quenching (NPQ) and the activities of peroxidase (POD) and ascorbate peroxidase (APX) to protect the photosynthetic structure. Low concentration of Sr (250 mg·L−1) promoted the photochemical efficiency and electron transfer of PSII (e.g., increased F v/F m, Φ PSII, qP and ETR). However, Sr (250–1,000 mg·L−1) inhibited the net photosynthetic rate (P n), transpiration rate (T r) and stomatal conductance (G s) in leaves. In general, the P n was affected by both stomatal and non-stomatal factors. Since Sr did not cause significant damage to the PSII function, the non-stomatal factor may be the dark reaction in photosynthesis affected, but this needs to be proved by further studies.

Exogenously Applied Rohitukine Inhibits Photosynthetic Processes, Growth and Induces Antioxidant Defense System in Arabidopsis thaliana.

The secondary metabolite rohitukine has been reported in only a few plant species, including Schumanniophyton magnificum, S. problematicum, Amoora rohituka, Dysoxylum acutangulum and D. gotadhora. It has several biological activities, such as anticancer, anti-inflammatory, antiadipogenic, immunomodulatory, gastroprotective, anti-implantation, antidyslipidemic, anti-arthritic and anti-fertility properties. However, the ecological and physiological roles of rohitukine in parent plants have yet to be explored. Here for the first time, we tried to decipher the physiological effect of rohitukine isolated from D. gotadhora on the model system Arabidopsis thaliana. Application of 0.25 mM and 0.5 mM rohitukine concentrations moderately affected the growth of A. thaliana, whereas a remarkable decrease in growth and the alteration of various morphological, physiological and biochemical mechanisms were observed in plants that received 1.0 mM of rohitukine as compared to the untreated control. A. thaliana showed considerable dose-dependent decreases in leaf area, fresh weight and dry weight when sprayed with 0.25 mM, 0.5 mM and 1.0 mM of rohitukine. Rohitukine exposure resulted in the disruption of photosynthesis, photosystem II (PSII) activity and degradation of chlorophyll content in A. thaliana. It also triggered oxidative stress in visualized tissues through antioxidant enzyme activity and the expression levels of key genes involved in the antioxidant system, such as superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Rohitukine-induced changes in levels of metabolites (amino acids, sugars, organic acids, etc.) were also assessed. In light of these results, we discuss (i) the likely ecological importance of rohitukine in parent plants as well as (ii) the comparison of responses to rohitukine treatment in plants and mammals.

Influence of Adding Plant Fly Ash on The Geotechnical Properties and Pollution of Sanitary Landfill Soil

This paper investigates the impact of the plant fly ash (dry tree leaves) addition on the geotechnical properties of the landfill soil, where an engineering laboratory landfill simulating a real landfill was manufactured. Two percentages of plant fly ash (10% and 15%) were used to reduce or prevent the penetration of heavy metals resulting from the decomposition of landfill waste into the soil and conducting laboratory tests such as the Atterberg test, specific gravity test, compaction test, permeability test, SEM test, and heavy metals analysis. The results of laboratory tests indicate a decrease in the plastic limit and the liquid limit with the addition of plant fly ash, as well as a decrease in the specific gravity and a decrease in dry unit weight with an increase in the need for water content when adding plant fly ash. In contrast, the permeability increased with the addition of plant fly ash. In the most important laboratory test, which is the chemical analysis of soil metals, the soil improved with plant fly ash gave results indicating a lower level of metals pollution at depths of (10 cm, 20 cm, and 30 cm) of soil layer compared to natural soil. The analysis was conducted on 7 basic pollutants (cadmium, copper, iron, Manganese, Zinc, Chromium, and lead), where the percentage of pollutants decreased in improved soil compared to natural soil under the same conditions by (50%, 74%, 62%, 68%, 60%, 68%, and 55%) respectively.

Uji Sinergitas Rendaman Tembakau (Nicotiana tabacum L.) dengan Jamur Trichoderma spp. Secara In Vitro dan Potensinya Sebagai Gabungan Biopestisida Alami

Management of plant pests and diseases can prevent crop failure of agricultural commodities. Trichoderma spp. is a type of biological control fungus. Tobacco can be used as a vegetable pesticide. However, the synergy of tobacco and Trichoderma spp. when applied simultaneously in controlling pathogens is not yet known, considering the content of the active compound nicotine in tobacco which has antifungal properties, it is necessary to conduct this study with the aim of knowing the effect of tobacco immersion on the growth of the fungus Trichoderma spp. and if there is no inhibition then both will have the potential as a combination of natural biopesticides. This study used a completely randomized design (CRD). The treatment tried was different concentrations of tobacco soak mixed with PDA as a culture medium for Trichoderma spp. The concentrations tested were 0% (T0, positive control), 5% (T1), 10% (T2), 15% (T3), and 20% (T4). The negative control used a fungicide with the active ingredient mankozeb. Each treatment was repeated 3 times. Colony thickness and color data were observed visually by descriptive method. Meanwhile, data on colony diameter, number of spores, dry weight of mycelium were analyzed by F test, if significantly different, then followed by DMRT test with a confidence level of 5%. Based on research that has been carried out from July-August 2021, the results obtained on PDA media with tobacco soaking content with concentrations of 0% (K+), 5% (T1), 10% (T2), 15% (T3), 20% (T4 ) can be grown with Trichoderma spp., while the media with the addition of synthetic fungicides made from mankozeb is not grown. The difference in concentration showed different growth results and the effective concentration in this research was 15%, because at 20% concentration there was a decrease in spore density and mycelium dry weight.

Katkı türü ve oranının yüksek plastisiteli kilin kompaksiyon parametrelerine etkisi

Stabilization, which is defined as the improvement of the geotechnical properties of clayey soils by using additives with pozzolanic properties, is highly preferred today because it is easy to apply, economical and many of them are environmentally friendly. As a result of the textural changes that occur after successful stabilization by adding different pozzolans to the clayey soils, the optimum water content value, which is called the compaction parameters of the soil, increases, while the maximum dry unit weight decreases. In this study, the effects of additives used in different types and ratios on the compaction parameters of high plasticity bentonite were investigated. For this purpose, samples with additives using slaked lime, fly ash, acidic and basic tuffs in different proportions were prepared and Standard Proctor tests were carried out on these samples. According to the results obtained from the studies, the best results were obtained in the case of using only one additive material, in the sample with 5% acidic tuff and in the sample with 10% slaked lime. In the examples where two types of additives were used together, the best results were obtained in the example where 10% acidic tuff and slaked lime were used together. The results obtained from this study show that the best results are obtained in compaction parameters, especially when slaked lime and acidic tuff additive are used together.

The involvement of extracellular ATP in regulating the stunted growth of Arabidopsis plants by repeated wounding

BackgroundExtracellular ATP (exATP) has been shown to act as a signal molecule for regulating growth, development, and responses of plants to the external environment.ResultsIn this study, we investigated the possible involvement of exATP in regulating the stunted growth caused by repeated wounding. The present work showed that the repeated wounding caused the decreases in leaf area, fresh weight, dry weight, and root length of Arabidopsis seedlings, while the exATP level was enhanced by the repeated wounding. Repeated application of exogenous ATP had similar effects on the plant growth, as the repeated wounding. Through the comparison of p2k1-3 mutant (in which T-DNA disrupted the gene coding P2K1, as exATP receptor) and wide type (WT) plants, it was found that the mutation in P2K1 decreased the sensitivity of plant growth to the repeated wounding and exogenous ATP application. Further works showed that the ibuprofen (IBU, an inhibitor of jasmonate biosynthesis) partially rescued the wound-induced growth degradation. In comparison, the P2K1 mutation partly rescued the wound-induced growth degradation, whereas this mutation failed to do so in the wounded seedlings treated with IBU, indicating that the role of exATP in regulating the growth degradation by repeated wounding could be linked to the JA signaling pathway.ConclusionsIn conclusion, these results indicate that exATP could be a regulator for the stunted growth of plants by repeated wounding.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12870-022-03656-z.

Role of Spermidine in Photosynthesis and Polyamine Metabolism in Lettuce Seedlings under High-Temperature Stress.

High temperature is a huge threat to lettuce production in the world, and spermidine (Spd) has been shown to improve heat tolerance in lettuce, but the action mechanism of Spd and the role of polyamine metabolism are still unclear. The effects of Spd and D-arginine (D-arg) on hydroponic lettuce seedlings under high-temperature stress by foliar spraying of Spd and D-arg were investigated. The results showed that high-temperature stress significantly inhibited the growth of lettuce seedlings, with a 33% decrease in total fresh weight and total dry weight; photosynthesis of lettuce seedlings was inhibited by high-temperature stress, and the inhibition was greater in the D-arg treatment, while the Spd recovery treatment increased net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), stomatal limit value (Ls), and intercellular CO2 concentration (Ci). High-temperature stress significantly reduced the maximum photochemical efficiency (Fv/Fm), photochemical quenching coefficient (qP), electron transport rate (ETR), and photochemical efficiency of PSII (ΦPSII), increased the non-photochemical burst coefficient (NPQ) and reduced the use of light energy, which was alleviated by exogenous Spd. The increase in polyamine content may be due to an increase in polyamine synthase activity and a decrease in polyamine oxidase activity, as evidenced by changes in the expression levels of genes related to polyamine synthesis and metabolism enzymes. This evidence suggested that D-arg suppressed endogenous polyamine levels in lettuce and reduced its tolerance, whereas exogenous Spd promoted the synthesis and accumulation of polyamines in lettuce and increased its photosynthetic and oxidative stress levels, which had an impact on the tolerance of lettuce seedlings.

Modulation of cytotoxic effects of wastewater on barely seedlings by Aloe vera extract

Aim: This study was conducted to assess the mitigation effect of A. vera leaf ethanolic and water extracts on plant growth, MDA and protein content, and mitotic index of barley seedlings irrigated with sewage water. Methodology: The experiment was conducted in a green house in Al-Ahsa, Saudi Arabia, in plastic bags containing air-dried loam soil and compost (1:1). Wastewater samples were collected from Al-Ahsa Sewage Treatment Plant/Al-Ahsa/Saudi Arabia. Seeds of barley were exposed to the following treatments for three weeks: 100% treated wastewater, treated wastewater mixed with: 0.05 g ml-1 A. vera alcoholic extract (Alc Ext) or 0.05 g ml-1 A. vera water extract (Wat Ext), 0.15 g ml-1 Alc Ext or 0.15 g ml-1 Wat Ext. Similar test doses were prepared for untreated wastewater. A separate set of seeds was prepared using distilled water as a control. Germination rate, fresh and dry weight, protein content, MDA content and mitotic index were determined. Results: Untreated wastewater caused significant reduction in fresh weight while both treated and untreated wastewater showed insignificant decrease in dry weight of barley. No significant change in MDA contents were observed in all treatments, except for addition of 0.15 A. vera water extract to untreated wastewater. Protein content showed an increase in both treated wastewater (insignificant) and untreated wastewater (significant). Addition of A. vera extracts increased accumulation of protein in both shoot and root. A. vera alcoholic extract promoted significant increase in both root and shoot protein of treated wastewater, but only shoot protein of untreated wastewater. A significant reduction in mitotic index was induced by wastewater, while addition of A. vera extracts stimulated significant increase in mitotic index. Interpretation: A. vera possess reactive oxygen species scavenging ability and enzyme conservation activity in addition to stimulatory effects on cell proliferation and cell-cycle process that add a modulation credit on protein content and mitotic index of barley.

Characterization of an alcohol acetyltransferase GcAAT responsible for the production of antifungal volatile esters in endophytic Geotrichum candidum PF005

Alcohol acetyltransferases (AATs) are a group of enzymes that catalyze the formation of esters from different alcohols and acetyl-CoA. However, these enzymes are not well characterized with regard to synthesis of antifungal compounds. The present study aims to investigate the AAT enzyme from Geotrichum candidum PF005, an endophytic yeast-like fungus that emits fruity scented antifungal volatiles, primarily comprising of acetate esters. After PCR-based cloning of the GcAAT gene, the encoded enzyme was characterized structurally through in silico methods and functionally via heterologous expression in Saccharomyces cerevisiae. In native host, the single copy GcAAT gene exhibited induced expression upon supplementation with metabolic precursors, like L-leucine (Leu) or α-ketoisocaproate (α-KIC). Docking studies using the modelled structure of GcAAT revealed differential but favourable binding interactions for three alcohol substrates (i.e., isoamyl alcohol, isobutyl alcohol and 2-phenylethanol) and the co-substrate acetyl-CoA. Binding sites for both substrate and co-substrate are found to be located inside a tunnel identified in the structure, wherein the H208 of the acetyltransferase conserved motif HXXXD was found at a hydrogen bond distance from the substrate. Functional complementation of GcAAT in S. cerevisiae AAT knockout strain caused 32% decrease in dry biomass weight of the test phytopathogenic fungus, Rhizoctonia solani as compared to the control (AAT knockout strain with empty plasmid) after 72 h of incubation due to the emitted volatiles. When the transformed yeast cells were fed with Leu and α-KIC, the relative abundance of the isoamyl acetate ester increased by 21% and 48%, respectively as compared to the control (without precursor). Further analysis documented that volatiles from α-KIC fed GcAAT transformant exhibited 58% higher antifungal activity against the test fungus R. solani than the control, engendered by increased oxidative stress that led to distorted mycelial morphology and increased hyphal branching. Together, the augmented antifungal effect displayed by the GcAAT expressing S. cerevisiae AAT knockout strain is clearly attributable to the acetate esters, especially isoamyl acetate, which are inherently produced in endophytic G. candidum PF005 as antifungal volatiles.

Allelopathic Effects of Arum cyreniacum on Germination and Growth of Two Varieties of Vicia faba

Two experiments were conducted (laboratory - pots) at the lab of Botany Department/ Faculty of Science/ Omar Al-Mukhtar University/ Al Bayda/ Libya, with the aim of determining the allopathic effects of aqueous extracts at concentrations of (10, 20, and 40%) and the crude powder added to the soil at concentrations of (1, 2, and 4%) of Arum cyreniacum (Tubers - Leaves) on the germination of seeds and the development of seedlings of two Vicia faba cultivars (local - Massa), with three replications according to a completely randomized design. The results of the laboratory experiment showed significant differences in the reduction of germination percentage, reduction of radicle and plumule lengths between the aqueous extracts, and concentrations of Vicia faba cultivars (local - Massa), compared with control. The results of a pot experiment also showed that the high concentrations significantly reduced the emergence percentage of seedlings, while all concentrations led to a clear and large reduction in root and shoot system lengths and a decrease in fresh and dry weights of seedlings of (local - Massa) cultivars. Most of the concentrations used caused an accumulation of chlorophyll (a) and carotenoids, and decreased the concentration of chlorophyll (b), it also led to an accumulation of potassium, iron, copper, and nickel, while they led to a decrease in the sodium concentration of two cultivars compared to the control, The tubers had the highest inhibition rates compared to the leaves, and the high concentrations of extracts and crude powder were the most toxic in inhibiting the growth of the studied traits of the two cultivars, Massa cultivar was more sensitive than the local cultivar.

PHYSIOLOGICAL RESPONSES OF AMARANTHUS HYBRIDUS L. UNDER SALINITY STRESS

Soil salinity is an abiotic factor that adversely affects growth and development of plants. To evaluate the physiological responses of Amaranthus hybridus L. under salinity stress, seedlings were exposed to 0, 0.1 and 0.2M NaCl for a period of 6 weeks. Whole plant dry weight, relative water content (RWC), total chlorophyll, lipid peroxidation, protein level and antioxidant enzymes activities were evaluated after the treatment period. The results of the study showed that salinity caused a significant decrease in whole plant dry weight, relative water content, total chlorophyll and protein content while an increase in malondialdehyde content, catalase and ascorbate peroxidase activities were observed. The severity of these effects was concentration dependent. The biomass accumulation of the control plants was 11.67±0.39 g, while those that received 0.1 and 0.2 M NaCl had 9.22±0.28 and 6.94±0.07 g respectively. The increase in malondialdehyde content and antioxidant enzymes activities were indications that salinity stress induced the production of reactive oxygen species (ROS) which caused oxidative damage to macromolecules in living cells

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.