Plant Amaranthus Research Articles

Bioinspired synthesis of ZrO2‐Zr3Er4O12‐based mixed nanomaterial; characterization and analyzing its potential as an electrode material in energy‐based devices and its electrocatalytic property

AbstractThe sustainable and ecofriendly synthesis of transition metal oxide‐based nanomaterials has always been a matter of concern. In this study, a bioinspired synthesis route was adopted to synthesize ZrO2‐Zr3Er4O12‐based mixed nanomaterial using leaf extract of medicinal plant Amaranthus viridis as reducing and stabilizing agent in replacement of the obnoxious chemicals which are a great threat to the sustainable environment. The synthesized material revealed the spherical shaped morphology through scanning electron microscopy, whereas crystal size of 15.7 nm was observed through Xray‐diffraction, and band gap value of 2.7 eV was acquired using Tauc plot. Newly synthesized ZrO2‐Zr3Er4O12 nanocomposite was then investigated for its role as electrocatalyst in a generation of energy through the hydrogen evolution reaction and oxygen evolution reaction. The ZrO2‐Zr3Er4O12‐based electrocatalyst showed better potential for hydrogen evolution reaction measurements with the overpotential value of 242 mV. Furthermore, the notable capacitance value of 495.6 F/g was obtained through cyclic voltammetry for energy storage studies. The cyclic stability was also analyzed using linear sweep voltammetry and results showed promising stability for 2000 cycles. Consequently, the green and economical synthesis route as well as promising electrochemical behavior of ZrO2‐Zr3Er4O12‐based electrode make it feasible choice for large scale application.

Mulching materials effect on soil temperature, moisture content, plant growth and yield of amaranthus plant

Mulching materials effect on soil temperature, moisture content, plant growth and yield of amaranthus plant

Zinc amendment as an effective tool in the management of cadmium toxicity: a case study with Amaranthus cruentus L

The unmanaged waste disposal, coupled with the increased industrialization and urbanization, has aggravated the problem of heavy metal contamination in the environment, especially in the agricultural soils. In view of this, the present study was planned to evaluate the effectiveness of zinc (Zn) in the amelioration of cadmium (Cd) toxicity in plants, thereby sustaining the crop productivity in near future. The experiment was performed in two parts. The first part focused on calculating the EC50 (half-effective concentration) of Cd, for which the potted experimental plants (Amaranthus cruentus L.) were treated with different doses of Cd (10, 20, 30, 40, and 50 mgL−1). In the second part, the EC50 Cd dose was combined with different Zn doses (100, 200, 300, 400, and 500 mgL−1) and the effect of Zn supplementation on Cd exposed plants was studied by evaluating the response of different biochemical, physiological and yield parameters. The EC50 Cd dose was calculated to be 26.5 mgL−1. Plant yield increased significantly with reduced Zn dosages. Biochemical parameters improved more than physiological parameters after Zn treatment in Cd-stressed plants. At higher Zn doses, its toxic effects exacerbate Cd toxicity. The study indicates that Zn partially decreases Cd toxicity in Amaranthus plants. The results suggest that 300 mgL−1 Zn dose was sufficient to bring about maximum recorded mitigation of Cd toxicity. However, since the synergistic effects of high doses of Zn with Cd cannot be ruled out, the selection of the applied Zn dose should be carefully selected.

The Invasive Plant Amaranthus spinosus L. Exhibits a Stronger Resistance to Drought than the Native Plant A. tricolor L. under Co-Cultivation Conditions When Treated with Light Drought.

Drought may facilitate the invasion process of invasive plants, mainly because invasive plants can obtain a stronger growth competitiveness than native plants under drought. It is therefore imperative to illuminate the mechanisms underlying the successful invasion of invasive plants under drought, with a particular focus on the differences in the resistance of invasive and native plants to drought. This study aimed to elucidate the differences in the resistance between the invasive plant Amaranthus spinosus L. and the native plant A. tricolor L. to drought under a gradient of drought. The resistance of co-cultivated A. spinosus to drought was significantly higher than that of co-cultivated A. tricolor under light drought. Hence, A. spinosus may obtain a stronger competitive advantage than A. spinosus under co-cultivation conditions when treated with light drought. The resistance of the two plants to drought may be predominantly influenced by their height and biomass. This present study also defines a method for evaluating the stress resistance of a given plant species to stress by calculating the stress resistance index. This present study offers a robust theoretical foundation for determining the stress resistance of a given plant species and the environmental management of A. spinosus under drought.

Synthesis of ZrO2‐NdO‐based mixed nanomaterial using green capping agent and its functionalization as electrode material for energy devices: Pseudo capacitors and water splitting

AbstractThis study investigates the environmentally friendly synthesis of ZrO2‐NdO mixed nanomaterial using green reducing and capping agents derived from the plant Amaranthus viridis. X‐ray diffraction (XRD) analysis confirmed the successful synthesis of the mixed nanomaterial, revealing an optical band gap of 2.5 eV. The morphology was characterized by spherical‐shaped particles with an average size ranging from 66 to 77 nm. The synthesized ZrO2‐NdO mixed nanomaterial was evaluated for its potential application as an electrode material in energy devices, specifically for pseudocapacitors and water splitting studies. Electrochemical performance was assessed using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques. Notably, a specific capacitance of 573.5 F/g was achieved through CV at a scan rate of 2 mV/s. Fabricated electrocatalyst was further analyzed for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the results showed better over potential value of 164 mV for HER studies. The stability analysis further endorsed the large‐scale commercialization possibility of ZrO‐NdO‐based electrode material.

Synthesis and Evaluation of New Phytotoxic Fluorinated Chalcones as Photosystem II and Seedling Growth Inhibitors.

The development of novel phytotoxic compounds has been an important aim of weed control research. In this study, we synthesized fluorinated chalcone derivatives featuring both electron-donating and electron-withdrawing groups. These compounds were evaluated both as inhibitors of the photosystem II (PSII) electron chain as well as inhibitors of the germination and seedling growth of Amaranthus plants. Chlorophyll a (Chl a) fluorescence assay was employed to evaluate their effects on PSII, while germination experiments were conducted to assess their impact on germination and seedling development. The results revealed promising herbicidal activity for (E)-3-(4-bromophenyl)-1-(4-fluorophenyl)prop-2-en-1-one (7 a) and (E)-1-(4-fluorophenyl)-3-phenylprop-2-en-1-one (7 e). Compounds 7 a and 7 e exhibited a reduction in Chl a parameters associated with performance indexes and electron transport per reaction center. This reduction suggests a decrease in PSII activity, attributed to the blockage of electron flow at the quinone pool. Molecular docking analyses of chalcone derivatives with the D1 protein of PSII revealed a stable binding conformation, wherein the carbonyl and fluorine groups interacted with Phe265 and His215 residues, respectively. Additionally, at a concentration of 100 μM, compound 7 e demonstrated pre- and post-emergent herbicidal activity, resulting in a reduction of the seed germination index, radicle and hypocotyl lengths of Amaranthus weeds.

Is the Invasive Plant Amaranthus spinosus L. More Competitive than the Native Plant A. tricolor L. When Exposed to Acid Deposition with Different Sulfur–Nitrogen Ratios?

The functional differences between invasive plants and coexisting native plants can affect the invasion process of the former because invasive plants and coexisting native plants are exposed to similar or even identical environmental pressures. Acid deposition is an important component of atmospheric pollution, and acid deposition with different sulfur–nitrogen ratios may affect the invasion process of invasive plants by shifting the functional differences and differences in the growth performance between the invasive and coexisting native plants. It is crucial to analyze the functional indices and growth performance of these plants when exposed to acid deposition with different chemical compositions to assess the ecological impacts of atmospheric pollution on the growth performance of invasive plants. This study aimed to evaluate the functional differences and growth performance between the invasive plant Amaranthus spinosus L. and the native plant A. tricolor L. in mono- and mixed culture when exposed to an acid deposition with different sulfur–nitrogen ratios, including sulfur-rich acid deposition (sulfur–nitrogen ratio = 5:1), nitrogen-rich acid deposition (sulfur–nitrogen ratio = 1:5), and mixed acid deposition (sulfur–nitrogen ratio = 1:1). The acidity of the three types of simulated acid deposition was set at pH = 5.6 and pH = 4.5, respectively, with distilled water as a control (pH = 7.0). The competition experiment between A. spinosus and A. tricolor was conducted in the greenhouse. Amaranthus spinosus exhibited a strong growth performance over A. tricolor in the mixed culture, mainly via the increased leaf photosynthetic capacity. The competitiveness for light acquisition, leaf photosynthetic capacity, and enzymatic defense capacity under stress of A. spinosus may be vital to its growth performance. The lower pH acid deposition had imposed a greater reduction in the growth performance of both Amaranthus species than the higher pH acid deposition. Sulfur-rich acid deposition was more toxic to the growth performance of both Amaranthus species than nitrogen-rich acid deposition. Amaranthus spinosus was more competitive than A. tricolor, especially when exposed to acid deposition, compared with just distilled water. Thus, acid deposition, regardless of the sulfur–nitrogen ratio, may facilitate the invasion process of A. spinosus via the stronger growth performance.

Bidesmosidic and monodesmosidic triterpenoid saponins from the grain of Amaranthus hypochondriacus

Five known bidesmosidic triterpenoid saponins (1–5) and their hydrolysates, namely two new monodesmosidic triterpenoid saponins (1′ and 2′) and three known saponins (3′–5′), were isolated from Amaranthus hypochondriacus seeds. The structures of the new compounds were determined using interpreting 1D and 2D nuclear magnetic resonance (NMR) data and high-resolution electrospray ionisation mass spectrometry (HRESI-MS) analyses as 3-O-β-D-glucuronopyranosyl-30-normedicagenic acid (1′) and 3-O-[α-L-rhamnopyranosyl (1 → 3)-β-D-glucuronopyranosyl] bayogenin (2′). For the first time, 5 and 5′ were isolated from Medicago plants as the first examples of glycosides in medicagenic acid from Amaranthus plants. While bidesmosidic saponins showed no cytotoxicity, monodesmosidic saponins, except for 1′, showed moderate cytotoxicity against human cervix adenocarcinoma (HeLa) cells. In addition, monodesmosidic saponins showed anti-fungal activity against the rice blast fungus (Pyricularia oryzae).

Pharmaceutical Activity of Medicinal Plant Amaranthus viridis Linn. Due to Its Chemical Constituents: A Review

Background: Amaranthus viridis, a herbal plant belonging to the family Amaranthaceae, has gained significant attention in the field of traditional medicine due to its rich chemical composition. This plant is known to contain various bioactive components that contribute to its pharmaceutical value. With its extensive range of chemical compounds, Amaranthus viridis has found applications in therapeutic, pharmaceutics, and cosmetic industries. In this study, we aim to explore the medicinal potential of Amaranthus viridis and investigate its various pharmaceutical activities. Methods: The process of writing this review involved conducting comprehensive electronic research using reputable sources, including international and national article databases, along with books accessed through platforms like Google Scholar, PubMed, IEEE Xplore, ScienceDirect and others. The gathered data is subsequently analyzed, followed by employing synthetic approaches with narrative methods to derive meaningful conclusions and interpretations. Results: Amaranthus viridis displays potent antioxidant and anti-inflammatory properties, attributed to its rich composition of flavonoids, cardiac glycosides, and zinc. Its diverse pharmaceutical activities make it a promising contender for medicinal use, addressing labor pain, skin conditions like eczema and psoriasis, and respiratory issues, while also exhibiting antimicrobial effects against bacteria, fungi, and parasites. It can be accomplished by Extraction with solvent, Phytochemical screening and Isolation and purification. Conclusion: Amaranthus viridis, a herbal plant, shows significant potential in therapeutic, pharmaceutics, and makeup industries. Its bioactive compounds, including flavonoids, cardiac glycosides, and zinc, contribute to its diverse pharmaceutical activities, such as antioxidant, anti-inflammatory, antibacterial, antifungal, antidiabetic, and antihelmintic properties.

A meta-analysis on the heavy metal uptake in Amaranthus species

Metals can accumulate in different parts of plant species in high concentrations, which gives the basis for the plant-based technology called phytoremediation. Among annual species, Amaranthus is a well-studied, potential metal accumulator genus; however, some conflicts are found among published results. Thus, we studied the metal (Cd, Cu, Fe, Ni, Pb, and Zn) accumulation potential of Amaranthus plant parts (root, stem, and leaf) by meta-analysis, furthermore, by calculation of bioaccumulation factor (BAF) values. After the extensive literature search and the calculation of relative interaction intensity (RII) values, we found significant accumulation for each metal by Amaranthus individuals growing on contaminated soils compared to plants collected from uncontaminated ones. Differences among plant parts were significant for Cu and Fe, minor for Ni, Pb, and Zn, and negligible for Cd. The BAF values indicated high accumulation in the leaf, moderate in root and stem for Cd, moderate in each plant part for Pb, and very low in each plant part for Fe, Ni, and Zn. We highlight that Amaranthus species are good prospects for metal phytoremediation projects, although, due to specific plant part-metal patterns, special attention should be paid to the harvesting practice.

The concurrent impacts of drought and leaf harvesting on two traditional African vegetable non-timber forest product species.

Investigating the concurrent impacts with harvesting on wild vegetables can guide their sustainable management while contributing to the understanding of such impacts on NTFP species. This study investigated leaf production, morphological and growth responses to the concurrent impacts of drought and leaf harvesting between two wild vegetables. A randomized greenhouse experiment was implemented with 1,334 plants of Amaranthus sp. and 391 of B. pilosa. A drought treatment was first implemented through six levels of drought stress and a control treatment. The harvesting treatment consisted of four harvesting levels and was implemented twice. Measurements were recorded before first and second harvests and at end of experiment. Data were separated into two periods (after first and second harvests) and analyzed using Multivariate Analysis of Variance and log-linear analysis. The results showed significant effects of drought on both species. However, Amaranthus sp. appeared more resilient to reduction in the daily amount of water than reduction in the frequency, while B. pilosa was resilient under both facets of drought stress. For Amaranthus sp., basal diameter, its growth, leaf production and survival increased with increase in the harvesting level (with some exceptions) after first harvest. After second harvest, there was decrease in plant height and leaf production. In B. pilosa, the impact was only significant on survival and leaf production (after first harvest). The effect of the interaction of the two drivers was significant for Amaranthus sp., but not for B. pilosa. The results also highlighted the possible negative impact of a prolonged high rate harvesting on the species performance, especially under severe drought. Basal diameter, its growth, survival and leaf production appeared more resilient to reduced amounts of watering in Amaranthus sp., and under both types of drought stress for B. pilosa. This suggests that both species could be sustained under medium drought stress.

Influence of Drought and Heat Stress on Mineral Content, Antioxidant Activity and Bioactive Compound Accumulation in Four African Amaranthus Species.

Drought and heat stress is known to influence the accumulation of mineral content, antioxidant activity, phenolics, flavonoids and other bioactive compounds in many tolerant leafy vegetables. Amaranthus plants can tolerate adverse weather conditions, especially drought and heat. Therefore, evaluating the influence of drought and heat stress on commercially and medically important crop species like Amaranthus is important to grow the crop for optimal nutritional and medicinal properties. This study investigated the influence of drought and heat stress and a combination of both on the accumulation of phenolic and flavonoid compounds and the antioxidant capacity of African Amaranthus caudatus, A. hypochondriacus, A. cruentus and A. spinosus. Phenolic and flavonoid compounds were extracted with methanol and aqueous solvents and were quantified using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Caffeic acid was the main phenolic compound identified in aqueous extracts of A. caudatus and A. hypochondriacus. Rutin was the most abundant flavonoid compound in all the Amaranthus species tested, with the highest concentration found in A. caudatus. The results suggest a strong positive, but species and compound-specific effect of drought and heat stress on bioactive compounds accumulation. We concluded that heat stress at 40 °C under well-watered conditions and combined drought and heat stress (at 30 °C and 35 °C) appeared to induce the accumulation of caffeic acid and rutin. Hence, cultivation of these species in semi-arid and arid areas is feasible.

The impact of Amaranthus diet on eicosanoid Profiles: exploring the role in cancer treatment through cyclooxygenase (COX) and lipoxygenase (LOX) pathways: A mini-review

Scientists worldwide have made significant progress in identifying various beneficial substances found in plants, known as nutraceuticals and phytochemicals, which can enhance the effectiveness of chemotherapy by inhibiting cell signaling mechanisms associated with chemo-resistance. However, there is a lack of research regarding the potential anticancer and chemo-preventative properties of numerous naturally occurring agents derived from Amaranthus plants, including nutraceuticals and phytochemicals. This mini-review aims to provide an up-to-date overview of the effects of an Amaranthus-based diet on the eicosanoid profiles of cyclooxygenase and lipoxygenase pathways for cancer treatment. Our research uncovered several promising agents isolated from amaranth plants, such as quercetin, rutin, apigenin, squalene, and certain phytosterols like spinasterol, which have demonstrated notable anticancer and anti-inflammatory properties. Furthermore, existing literature indicates that these nutraceuticals can effectively inhibit the biosynthesis of COX and LOX enzymes, consequently suppressing the production of eicosanoids such as prostaglandins, prostacyclin, and leukotrienes. Hence, the nutraceuticals and phytochemicals derived from amaranth plants have the potential to serve as valuable adjunctive therapies, enhancing the efficacy of existing chemotherapy as clinically beneficial anticancer chemosensitizers.

The anticancer and anti-inflammatory effects of polyherbal drug AS20 on HeLa cells resistant to 5-Fluorouracil

Cancer treatment that involves chemotherapy often results in developed drug resistance which can be a major deterrent for the success of a treatment protocol. Increased inflammation, due to the drug's presence, contributes to disease progression and increased Cyclooxygenase-2 (COX2) expression (inflammatory marker). Integrative oncology is a field that focuses on combining natural herbal formulations with standard care to provide optimal clinical outcomes in a holistic manner, to minimize side effects, and to overcome drug resistance, including inflammation. 5-Flurouracil (5-FU) is a chemotherapeutic medication used to treat cancers. We studied drug resistance by deriving 5-FU-resistant HeLa cells (HeLa R) and evaluating the efficacy of AS20 in in vitro experiments. AS20 is an herbal formulation derived from the plant Amaranthus spinosus, an indigenous plant found in India. It contains different types of secondary metabolites such as saponins, polyphenols, alkaloids, terpenoids, and flavonoids. We hypothesized that AS20 has anti-inflammatory and anticancer properties on HeLa R. We investigated if AS20 could downregulate increased inflammatory markers such as COX2 in HeLa R. Also, we studied anti-apoptotic and pro-apoptotic genes in AS20 treated HeLa R cells. Our results demonstrated that the inhibitory concentration at 50% (IC50) values of HeLa wild type cells with AS20 treatment was significantly less than HeLa R cells. Also, AS20 brought down induced COX2 expression in HeLa R cells. AS20 treatment on HeLa R cells showed upregulation of BAX (pro-apoptotic) but no significant change in BAD (pro-apoptotic) and downregulation of BCL2 and BCL2L1 (anti-apoptotic genes) in HeLa R cells. Our results showed that AS20 has anti-inflammatory and pro-apoptotic properties when treated on HeLa R cells.

The weevil, Hypolixus pica (F.) (Coleoptera: Curculionidae) as a potential biological control agent of Amaranthus species (Amaranthaceae) in Adana Province, Turkey

Amaranthus species (Family) are among the most important weeds in summer crops and orchards in Turkey. The detrimental effects of pesticides on the environment and human health and the development of high levels of resistance to several herbicide classes by Amaranthus species have generate interest in alternative weed control methods. Since the biological control of weeds has gained great prominence recently, this study was carried out to determine the potential biological control agents of Amaranthus spp. in Adana Province. Turkey. For this aim, ten randomly selected fields randomly were in three districts (Yüreğir-Ceyhan-İmamoğlu). In each field, ten Amaranthus plants were collected randomly and dissected, and the numbers of the weevils and theirdifferent stages were recorded. In this study, three Amaranthus species were identified and A. palmeri was the most common, followed by A. retroflexus and A. spinosus. Fifty-nine larvae, 26 pupae and 10 adults were collected from the Amaranthus plants. All adult individuals were identified as H. pica according to their genital organs. Our results show that H. pica could be considered to be a potential biological control agent of A. palmeri and A. retroflexus. More detailed studies are needed to determine its ecology and role as a biological control agent of the target weed species. In addition, it is crucial to develop mass rearing methods for potential beneficial insects such as H. pica.

Potential distribution prediction of Amaranthus palmeri S.Watson in China under current and future climate scenarios.

The vicious invasive alien plant Amaranthus palmeri poses a serious threat to ecological security and food security due to its strong adaptability, competitiveness, and herbicide resistance. Predicting its potential habitats under current and future climate change is critical for monitoring and early warning. In this study, we used two sets of climate data, namely, WorldClim1.4 and RCPs (the historical climate data of WorldClim version 1.4 and future climate data of RCPs), WorldClim2.1 and SSPs (the historical climate data of WorldClim version 2.1 and future climate data of SSPs), to analyze the dominant environmental variables affecting the habitat suitability and predict the potential distribution of A.palmeri to climate change in China based on the MaxEnt model. The results show that (i) Temperature has a greater impact on the distribution of A.palmeri. The relative contributions of temperature-related variables count to 70% or more, and the annual mean temperature (bio1) reached more than 40%. (ii) At present, the potentially suitable area is widely distributed in the central-east and parts of southwest China, and the high suitable area is focused on the North China Plain. The potential suitable area predicted by WorldClim1.4 and WorldClim2.1 both accounts for about 31% of China's total land area. (iii) Future climate change will expand the suitable habitats to high latitudes and altitudes. The overall suitable area maximum increased to 44.93% under SSPs and 38.91% under RCPs. We conclude that climate change would increase the risk of A.palmeri expanding to high latitudes and altitudes, the results have practical implications for the effective long-term management in response to the global warming of A.palmeri.

ОНТОМОРФОГЕНЕЗ РОСЛИН ВИДІВ РОДУ AMARANTHUS L. В УМОВАХ КРЕМЕНЕЦЬКОГО БОТАНІЧНОГО САДУ

One of the important areas of modern science is the conservation of biodiversity, including plant diversity, which occurs through the introduction. Among the introducers are species of the genus Amaranthus L., which are promising for use in many sectors of the economy. Species of the genus are well known in crop production, and fodder production, and are becoming more widespread as food, medicinal, and technical plants. Due to the high productive potential of sagebrush plants and the multifunctional value of raw materials, there is a problem in the widespread production of crops in production. This raises a number of questions related to the study of the features of plant ontogenesis.
 The article presents the results of observations of introduced species of the genus Amaranthus L. in the Kremenets Botanical Garden. Purpose – to establish THE ontomorphogenesis peculiarities of Amaranthus plant species in conditions of introduction to the Kremenets Botanical Garden. The subject of the investigation is species of the genus Amaranthus. Investigations were conducted in 2019–2021 years on the introduction plot of the department of medicinal and new crops of Kremenets Botanical Garden. The developmental state was allocated according to descriptions of the methodology ontogenesis of T. A. Rabotnov.
 Peculiarities of ontomorphogenesis of ten collection specimens of the genus Amaranthus are the following: A. caudatus L. cv. Carmine, A. caudatus L. cv. Zolotystyi, A. caudatus L. cv. Kremovyi ranniy, A. caudatus L. cv. Kharkyvskyi, A. caudatus L. cv. Rushnychok, A. caudatus L., A. cruentus L. cv. Bulavovydnyi, A. hybridus L. cv. Atlant, A. paniculatus L., A. leucospermus S.Wats. The general botanical description of species of the genus is given, and the analysis of the biometric parameters of the shoots is given. During the ontogenesis of plants of the genus, Amaranthus undergo different age changes, characterized by structural and biological features. A full cycle of ontognesis takes one year. It was found that introduced plants of the genus Amaranthus species in conditions of culture have four age periods: latent, pregenerative, generative, postgenerative and developmental states: seeds, sprouts, juvenile, immature, virginal, generative, and dying. The generative period lasts the longest, beginning in the second or third decade of July and lasting until the first decade of October. It is established that the duration of the vegetation period of species of the genus Amaranthus in the Kremenets Botanical Garden is 130–137 days. The shortest phase of budding is 13–22 days. The longest vegetative phase is 42–58 days and the flowering phase is 22–33 days. The duration of all phases of development depends on species characteristics and weather conditions.

Association of seven ‘Candidatus Phytoplasma’ species to an almond disease complex in Jordan, and preliminary information on their putative insect vectors

During field surveys carried out from June to October 2020 and in January 2021 in orchards of northern Jordan, phytoplasma-like symptoms (early flowering along with evergreen pattern; witches’-broom, yellowing, and dieback; slim leaf and leaf rolling; stem fasciation) were observed in almond trees. In 23 investigated orchards, symptomatic almond trees ranged from 20 to 85%. PCR-based amplification of 16S rRNA gene detected phytoplasmas in 21% of 140 collected symptomatic almond trees. Sequence analyses allowed attributing the detected phytoplasmas to ‘Candidatus Phytoplasma asteris’ (taxonomic subgroups 16SrI-B and -R), ‘Ca. P. aurantifolia’ (16SrII-B and -C), ‘Ca. P. omanense’ (16SrXXIX-A and -B), ‘Ca. P. phoenicium’ (16SrIX-B), ‘Ca. P. pyri’ (16SrX-C), ‘Ca. P. solani’ (16SrXII-A), and ‘Ca. P. ulmi’ (16SrV-A). Such phytoplasmas were found associated with specific symptoms and differentially distributed in the considered locations. Moreover, further investigation identified ‘Ca. P. asteris’ (subgroup 16SrI-R) in putative insect vectors such as Empoasca sp., Reptalus sp., and Hyalesthes obsoletus, ‘Ca. P. pyri’ in Cacopsylla bidens, and ‘Ca. P. omanense’ (subgroup 16SrXXIX-B) in the non-crop plant Amaranthus sp. In conclusion, this study described an almond disease complex associated with multiple phytoplasmas, including ‘Ca. P. pyri’, ‘Ca. P. omanense’, and ‘Ca. P. ulmi’ that were never reported before in this crop. Further studies are needed to survey the diffusion of this almond disease complex in the region, demonstrate the transmission capability of the identified putative vectors, and in-depth investigate the ecologies of all phytoplasmas associated with the disease.

Effects of damping-off fungus on seed germination of amaranth (Amaranthus Hybridus)

Seed borne pathogens are microorganisms that can prevent seed germination and cause serious threats to seedling development in the field. The research was conducted on the effects of damping off fungus on seed germination of Amaranth (Amaranthus hybridus) collected from some Agricultural farmland in Lapai Local Government Area of Niger State, North central Nigeria. The isolation of fungal species from Amaranthus hybridus seeds of the infected plants having symptoms of damping off disease using agar plate method and was identified using the morphological characteristics features from mycological atlas. Isolation from the infected seeds revealed that Rhizoctonia solani were associated with the plants. Seed weight (mg) and seed germination (%) were determined using the international rules for seed testing and the physiological seed quality indices were determined; these are germination index (GI), germination rate index (GRI) and seedling vigor index were arranged in Randomized Complete Block Design (RCBD) all in triplicates. The result indicated that seeds from uninfected plants recorded seed weight (8.97mg) as compared with the infected seeds (5.21mg), there was significantly higher germination (98.67%) observed in uninfected seeds compared with seeds of Amaranthus plants that were infected (32.13%) with damping off fungus. Germination index was observed to be higher in seeds of uninfected plants (9.34) and lower in seeds of infected plants (4.34). The significant effects observed of the fungus on both seed and seedlings are highly virulence on the infected plants. The research revealed that a very good association between Rhizoctonia solani causing damping off disease and seed germination failure of Amaranthus hybridus plants. In the cultivation of Amaranthus hybridus, seed weight, and physiological seed quality attributes should be considered for an effective damping off disease suppression.

The interactive effects of drought and heat stress on photosynthetic efficiency and biochemical defense mechanisms of Amaranthus species.

Drought and heat stress are major abiotic stress factors that limit photosynthesis and other related metabolic processes that hamper plant growth and productivity. Identifying plants that can tolerate abiotic stress conditions is essential for sustainable agriculture. Amaranthus plants can tolerate adverse weather conditions, especially drought and heat, and their leaves and grain are highly nutritious. Because of these traits, amaranth has been identified as a possible crop to be grown in marginal crop production systems. Therefore, this study investigated the photochemical and biochemical responses of Amaranthus caudatus, Amaranthus hypochondriacus, Amaranthus cruentus, and Amaranthus spinosus to drought stress, heat shock treatments, and a combination of both. After the six-leaf stage in a greenhouse, plants were subjected to drought stress, heat shock treatments, and a combination of both. Chlorophyll a fluorescence was used to evaluate the photochemical responses of photosystem II to heat shock while subjected to drought stress. It was found that heat shock and a combination of drought and heat shock damages photosystem II, but the level of damage varies considerably between the species. We concluded that A. cruentus and A. spinosus are more heat and drought-tolerant than Amaranthus caudatus and Amaranthus hypochondriacus.