Dormancy of Amaranthus retroflexus L. Seeds and Physiological Response Seedlings to Acifluorfen Sodium

Amaranthus retroflexus L. is a serious and widespread malignant weed in soybean fields in Heilongjiang Province. Exploring the dormancy characteristics of A. retroflexus L. seeds and the physiological response of its seedlings to acifluorfen sodium can provide a basis for further researches on its resistance mechanism. Using newly harvested and stored A. retroflexus L. seeds for one year as experimental materials, the effects of different concentrations of HCl, NaOH, water temperature, gibberellic acid(GA) and polyethylene glycol(PEG) on the dormancy and germination of A. retroflexus L. seeds were studied. The sensitivity of A. retroflexus L.to acifluorfen sodium was determined using bioassay. The effects on leaf chlorophyll content and target enzyme activity were studied at a normal dosage of 360 g a.i. hm^(-2) and a doubling dosage of 720 g a.i. hm^(-2) of acifluorfen sodium. Newly harvested seeds exhibiting dormancy were soaked in water of various temperatures and in different concentrations of NaOH and HCl, which were ineffective in breaking the seed dormancy. GA could break seed dormancy, and the highest seed germination rate reached 93.33% when they were soaked at 3 000 mg·L^(-1) for 72 h and 4 000 mg·L^(-1) for 48 h. The drought stress was simulated with a 15%-25% polyethylene glycol solution, which had no significant effect on the seed germination rate. The GR_(50) value of acifluorfen sodium for A. retroflexus L. was 705.7 g a.i. hm^(-2), which was 1.96 times the recommended dose in the field. After the application of different doses of acifluorfen sodium, the chlorophyll content of A. retroflexus L. reached its minimum value 3 days after treatment(DAT), and then gradually increased. The activity of the target enzyme protoporphyrinogen oxidase(PPO) reached the highest value at 7 DAT under different dosages, and gradually returned to normal levels thereafter. Soaking with gibberellin was an effective method to break seed dormancy. A. retroflexus L. seeds had certain drought resistance during the germination process. A. retroflexus L. was not sensitive to acifluorfen sodium and acifluorfen sodium ether, and could not effectively inhibit the PPO activity, indicating that A. retroflexus L. had target resistance to acifluorfen sodium.

Herbicidal activity and biochemical characteristics of the botanical drupacine against Amaranthus retroflexus L.

Botanical herbicide has been a hot topic in the research and development of novel pesticides. The herbicidal activity and biochemical characteristics of the botanical compound drupacine were studied by evaluating its effects on seed germination, seedling growth, morphological and physiological characteristics of Amaranthus retroflexus. Drupacine inhibited seed germination and seedling growth, and had a median inhibition concentration(IC50) value of 38.99 mg L-1against A. retroflexus root. The α-amylase activity and soluble sugar content in treated plants were significantly lower than that of the control. The expression of α-amylase gene was dosage-dependently inhibited compared to the untreated control. This suggested that inhibition of α-amylase activity was a mode of action on seed germination. The root hairs were significantly decreased and part of the root cap fell off after treatment with drupacine. The ultrastructure observation showed that cell damage of root tips increased with the treatment time. Drupacine also increased the relative conductivity and malondialdehyde(MDA) content. Peroxidase(POD), catalase(CAT), and superoxide dismutase(SOD) activities were significantly enhanced in the treatment compared to the control. These findings indicated that the physiological and biochemical reaction changes leading to morphological and membrane injuries were the main effects of drupacine on the inhibition of seedling growth. Drupacine can be developed as a botanical herbicide.

Genome-Wide Identification and Characterisation of Abiotic Stress Responsive mTERF Gene Family in Amaranthus hypochondriacus

Abiotic stresses at different growth stages in the life of plants negatively affect yield productivity.Therefore,plants,including Amaranthus hypochondriacus,develop adaptive strategies to face the stresses and expand functional diversification.In plants,the mitochondrial transcription termination factors(mTERF)are essential functions in regulation,and organelles(mitochondria and chloroplasts)control gene expression(OGE)under several stress conditions.Based on the in-silico-wide genome and transcriptome analysis,twenty-four mTERF genes were detected in the main targeted mitochondria organelles clustered into three different main groups.The chromosomal location and gene duplication analysis indicated one segmental and one tandem duplication in the genome.The promoter region cis-elements assessment showed that there wasa high correlation between the growth and development process,stress,and hormone responses of these genes.Expression profiling of mTERF genes under salt stress revealed a total number of 24 gene families with seven upregulated and 6 down-regulated genes in drought and salt stress.However,Ah-mTERF-8 and 14 indicated up-regulation under drought stress.Ah-mTERF-4,6,14,15,17,and 20 were up-regulated under salt stress.Molecular characterization and identification through the in-silico study of the specific genes and their differential expression profiling demonstrated the role of mTERF proteins throughout their reaction to growth and development,during stress in A.hypochondriacus.These results demonstrated that mTERF genes were significantly related to the abiotic stress responses.

Effects of Electroplating Effluents on Growth, Heavy Metals Accumulation and Concentrations in Amaranthus viridis Lin.

Pollution in recent times has become prevalent due to industrial expansion,hence,releasing pollutants into the environ-ment.Thus,this study aimed at investigating the effects of effluents from electroplating companies on growth,heavy metals accumulation and concentrations in Amaranthus viridis.Seeds of A.viridis were obtained from the National Institute of Hor-ticulture,Ibadan.Loam soils were collected from Lagos State University and two samples of electroplating effluents were obtained from Oregun,Lagos.Seeds were sown,nursed,and transplanted in a uniform bucket filled with 5 kg loam soil and transplanted seedlings were treated with Effluent A(5 and 10%conc.)and Effluent B(5 and 10%conc.)and control respec-tively.Growth parameters such as plant height and so on were measured and plant samples harvested were analyzed for heavy metal concentrations using Atomic Absorption Spectrophotometer.Data collected were subjected to a one-way analysis of variance.Results revealed that Effluents A and B are highly acidic and above discharge limits.Also,the result revealed that 5%conc.of Effluents A and B had more effects on growth(p<0.05)of A.viridis across the harvests than 10%conc.in relation to control.This result showed that the effluent samples affect the growth rhythms of plants.Results further revealed vigorous–1–1 accumulation of the heavy metals:Zn(241.66µg kg±0.10 at third harvest in Effluent A:10%),Cu(68.25µg kg±0.23 at–1–1 first harvest in Effluent B:5%),Cr(500µg kg±0.90 in harvests at all concentrations.)and Ni(500µg kg±0.90 at third harvest in Effluent B:5%)and all these metals are far above the control and permissible limits of WHO/FAO recommenda-tions.From this study,it could be concluded that electroplating effluents had adverse effects on growth and increased metals’bioaccumulation in A.viridis.Therefore,the treatment of effluents to enhance an eco-friendly environment should be done.

Anti-diabetic and anti-cholesterolemic activity of methanol extracts of three species of Amaranthus

Objective:To investigate the anti-diabetic and anti-cholesterolemic activity of methanol extracts of leaves of Amaranthus caudatus,Amaranthus spinosus and Amaranthus viridis in normal and streptozotocin(STZ) induced diabetic rats.Methods:In this study,the anti-diabetic and anti-cholesterolemic activity of methanol extracts of leaves of all three plants was evaluated by using normal and STZ induced diabetic rots at a dose of 200 mg/kg and 400 mg/kg p.o.daily for 21 days.Blood glucose levels and body weight were monitored at specific intervals,and different biochemical parameters,serum cholesterol,serum triglyceride,high density lipoprotein, low density lipoprotein and very low density lipoprotein were also assessed in the experimental animals.Histology of pancreas was performed.Results:It was found that all the three plants at 400 mg/kg dose showed significant anti-diabetic and anti-cholesterolemic activity(P<0.01),while at 200 mg/kg dose less significant anti-diabetic activity(P<0.05) was observed.Concluslons: Methanol extracts of Amaranthus caudatus,Amaranlhus spinosus and Amaranthus viridis showed significant anti-diabetic and anti-cholesterolemic activity,which provides the scientific proof for their traditional claims.

Antioxidant and antipyretic properties of methanolic extract of Amaranthus spinosus leaves

Objective:Methanolic extract of Amaranthus spinosus（A.spinosus） leaves was screened for antioxidant and antipyretic activities.Methods:Antioxidant activity was measured by l,l-diphenyl-2-picryl-hydrazile（DPPH） free radical scavenging,superoxide anion radical scavenging,hydroxyl free radical scavenging,nitric oxide radical scavenging,2,2 -azinobis-3- ethylbenzothiazole-6-sulfonic acid（ABTS） radical scavenging assays and total phenolic content was also determined.Antipyretic activity of methanolic extract of A.spinosus was measured by yeast induced pyrexia method at concentration of 200 and 400 mg/kg using paracetamol as standard drug.Results:Methanolic extract of A.spinosus showed potent antioxidant activity.The IC50 value was（87.50±3.52）μg/mL,（98.80±1.40）μg/mL,（106.25±0.20）μg/mL,（88.70±0.62）μg/mL and（147.50±2.61）μg/mL for DPPH,superoxide,hydroxyl,nitric oxide and ABTS radical scavenging activities.Methanolic extract of A spinosus showed significant（P【0.01） antipyretic activity.

Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions

Plants synthesize the osmoprotectant glycine betaine (GB) via choline→betaine aldehyde→glycine be- taine[1]. Two enzymes are involved in the pathway choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). A full length CMO cDNA (1,643bp) was cloned from Amaranthus tricolor. The open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with CMOs in Spina- cia oleracea L. and Beta vulgaris L. DNA gel blot analysis indicated the presence of one copy of CMO gene in the A. tricolor genome. The expressions of CMO and BADH proteins in A.tricolor leaves significantly increased under salinization, drought and heat stress (42℃), as determined by immunoblot analysis, but did not respond to cold stress (4℃), or exogenous ABA application. The increase of GB content in leaves was parallel to CMO and BADH contents.

Effects of Copper on the Photosynthesis and Oxidative Metabolism of Amaranthus tricolor Seedlings

The objective of the present study was to gain better insight into the physiological mechanisms on the effects of copper （Cu） on photosynthesis and active oxygen metabolism in three-colored amaranth plant （Amaranthus tricolor）. Three- colored amaranth seedlings were subjected to different Cu levels in soils during the entire experimental period. The parameters of growth, photosynthesis, mineral elements contents, and active oxygen metabolism were investigated using plant physiological methods. The results showed that 2.0 and 4.0 mmol Cu kg^-1 treatments decreased the whole plant biomass to 91 and 73% of the control, respectively. The net photosynthetic rate （Pn） and the stomatal conductance （gs） were similarly reduced in the third leaves of three-colored amaranth seedlings treated with 2.0 and 4.0 mmol Cu kg^-1 soil, respectively. None of the investigated Cu levels decreased the internal CO2 concentration （Ci）. The effect of Cu on the potential efficiency of photosystem Ⅱ （Fv/Fm） was negligible, whereas the effect of Cu on the PS Ⅱ quantum efficiency （ΦPS Ⅱ） after plant adaptation in actinic irradiation was more noticeable. On the other hand, decreases in water percentage, contents of photosynthetic pigments and mineral elements including Fe, K, and Mg, and significant increase in the Cu content were observed in the third leaves of Cu-treated plants. Superoxide dismutase （SOD） and peroxidase （POD） activities as well as the proline （Pro） content significantly increased in the third leaves of the three-colored amaranth seedlings treated with 2.0 and 4.0 mmol Cu kg^-1 soil, while catalase （CAT） and ascorbate peroxidase （APX） activities as well as the contents of carotenoid （Car）, glutathione （GSH）, and ascorbic acid （AsA） decreased, and accompanied by the increases in the contents of hydrogen peroxide （H2O2）, superoxide anion （O2^-）, and malondialdehyde （MDA）, and electrolyte leakage. As a result of the imbalance of active oxygen metabolism, Pn and ΦPS Ⅱ decreased, and peroxidization enhanced under levels of 2.0 and 4.0 mmol Cu kg^-1 soil. Finally, the growth of three-colored amaranth plant was significantly inhibited.

Amaranthus roxburghianus root extract in combination with piperine as a potential treatment of ulcerative colitis in mice

OBJECTIVE： The present work was undertaken to determine the effects of Amaranthus roxburghianus Nevski. （Amaranthaceae） root alone and in combination with piperine in treating ulcerative colitis （UC） in mice. METHODS： Swiss albino mice were divided into seven groups （n = 6）. Standard group received prednisolone （5 mg/kg, intraperitoneally）. Treatment groups received hydroalcoholic extract of roots of A. roxburghianus （50 and 100 mg/kg, per oral） and a combination of hydroalcoholic extract of roots of A. roxburghianus （50 and 100 mg/kg, per oral） and piperine （5 mg/kg, per oral）. Ulcer index, colitis severity, myeloperoxidase （MPO）, malondialdehyde and glutathione were estimated from blood and tissue. Column chromatography of the extract was done and purified fractions were analyzed by gas chromatography-mass spectroscopy （GC-MS）. RESULTS： Treatment with the combination of hydroalcoholic extract of A. roxburghianus and piperine showed minimal ulceration, hemorrhage, necrosis and leucocyte infiltration by histopathological observation. Acetic acid increased MPO levels in blood and colon tissue to 355 U/mL and 385 U/mg, respectively. The combination of hydroalcoholic extract of A. roxburghianus （100 mg/kg） and piperine （5 mg/kg） significantly decreased MPO in blood and tissue to 182 U/mL and 193 U/mg, respectively （P 〈 0.05）. Similarly, this combination significantly reduced malondialdehyde levels and increased glutathione levels in blood and tissue. Various phytoconstituents were detected by GC-MS. CONCLUSION： The combination of hydroalcoholic extract of A. roxburghianus and piperine is effective in the treatment of UC and the effects are comparable with the standard drug prednisolone. 4H-pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl, eugenol and benzene, and 1-（1,5-dimethyl-4-hexenyl）-4-methyl are reported having analgesic, anti-inflammatory, and antioxidant properties; they may play a role in the biological activity of A. roxburghianus root.

An ABAGE-Like Metabolite of Botrytis cinerea Isolate BC4 Inhibited the Growth of Hypocotyls and Roots of Amaranthus retroflexus Seedlings

A metabolite, which had an inhibitory effect on plant growth, was isolated from cultural filtrate of Botrytis cinerea isolate BC4 by column chromatography on silica gel and preparative HPLC. Its structure was determined from HPLC-ESI MS, GC, IR, ^1H NMR and ^13C NMR spectral data, as well as chemical hydrolysis. The results showed that this metabolite was quite similar to abscisic acid-β-D-glucopyranosyl ester（ABAGE） in structure. The inhibitory effect of the ABAGE-like metabolite on plant growth was investigated using a weed Amaranthus retroflexus L. as a bioassay material. The results showed that it inhibited hypocotyls and roots growth of A. retroflexus （Amaranthus retroflexus L.） seedlings when its concentration was over 0.5 μM. The concentrations for 50% inhibition of hypocotyls and roots growth of A. retroflexus seedlings were 2.8 and 1.4 μM, respectively.

Extraction and Purification Process Optimization and Antioxidant Activity in vitro of Flavonoids in Amaranthus caudatus L.

[Objectives]To explore the optimal extraction and purification process of the flavonoids in Amaranthus caudatus L.and to study the antioxidant activity in vitro of the flavonoids in A.caudatus.[Methods]Taking A.caudatus as the raw material,flavonoids were extracted by alcohol extraction method,and AB-8 macroporous adsorption resin was selected for purification.The hydroxyl radical scavenging ability,DPPH radical scavenging ability,and O^2-radical scavenging ability were used as evaluation indicators,to explore the antioxidant activity in vitro of the flavonoids in A.caudatus.[Results]The optimal extraction process conditions of flavonoids in A.caudatus are:liquid-to-material ratio 40:1,extraction temperature 60℃,ethanol concentration 60%,ultrasonic power 320 W,extraction time 50 min.Under these conditions,the extraction yield of flavonoids in A.caudatus is(1.35±0.01)%.The optimal purification process conditions of flavonoids in A.caudatus are 2.5 g AB-8 macroporous adsorption resin,sample volume 5 mL,mass concentration of adsorption solution 1.60 mg/mL,pH value of adsorption solution 3.0,sample flow rate 3 BV/h,ethanol concentration in desorption process is 70%and the desorption flow rate is 3 BV/h.Under these conditions,the recovery rate reaches 88.35%±0.68%.[Conclusions]A.caudatus has a high content of flavonoids and has excellent free radical scavenging ability in vitro.This study is intended to provide important technical support for the research of flavonoid activity of A.caudatus and the development of functional products.

Bioassay and Characterization of Several Palmer Amaranth (<i>Amaranthus palmeri</i>) Biotypes with Varying Tolerances to Glyphosate

The wide distribution of Palmer amaranth (Amaranthus palmeri) in the southern US became a serious weed control problem prior to the extensive use of glyphosate-resistant crops. Currently glyphosate-resistant populations of Palmer amaranth occur in many areas of this geographic region creating an even more serious threat to crop production. Investigations were undertaken using four biotypes (one glyphosate-sensitive, one resistant from Georgia and two of unknown tolerance from Mississippi) of Palmer amaranth to assess bioassay techniques for the rapid detection and level of resistance in populations of this weed. These plants were characterized with respect to chlorophyll, betalain, and protein levels and immunological responses to an antibody of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) the target site of glyphosate. Only slight differences were found in four biotypes grown under greenhouse conditions regarding extractable soluble protein and chlorophyll content, but one biotype was found to be devoid of the red pigment, betalain. Measurement of early growth (seedling shoot elongation) of seedlings was a useful detection tool to determine glyphosate resistance. A leaf disc bioassay (using visual ratings and/or chlorophyll analysis) and an assay for shikimate accumulation were effective methods for determining herbicide resistance levels. The two unknown biotypes were found to be resistant to this herbicide. Some differences were found in the protein profiles of the biotypes, and western blots demonstrated a weak labeling of antibody in the glyphosate-sensitive biotype, whereas strong labeling occurred in the resistant plants. This latter point supports research by others, that increased copy number of the EPSPS gene (and increased EPSPS protein levels) is the resistance mechanism in this species. Results indicate the utility of certain bioassays for the determination of resistance and provide useful comparative information on the levels of inherent constituents among closely related plants.

Effects of Nitrogen on the Competitiveness of Echinochloa colona and Amaranthus viridis with Direct-seeded Rice

Information on weed competitiveness responses to added nitrogen （N） is required to assist with the development of appropriate fertilizer management strategies where weed competition is anticipated. A greenhouse study was conducted to examine the effects of four N rates on the competitive ability ofEchinochloa colona and Amaranthus viridis grown together with direct-seeded rice. Rice and each weed species were grown in a replacement series design at added N rates of 0, 50, 100, and 150 kg ha1. Replacement series diagrams for relative yield showed that competitive ability ofE. colona increased with added soil N. Values of weed aggressivity index for E. colona also significantly increased with the addition of N in the soil. In the absence of added N, A. viridis was more competitive than rice but this relationship slightly changed as N was added. However, values of weed aggressivity index of were statistically similar at all N rates. The results suggest that the competitiveness ofE. colona increased with added soil N, and A. viridis unchanged by soil N levels. Both weed species were different in their response to higher N levels. Information gained in this study could be used to demonstrate the importance of effective weed and fertilizer management.

Implication of Ions and Organic Solutes Accumulation in Amaranth (<i>Amaranthus cruentus</i>L.) Salinity Resistance

Salinity is one of the major environmental constraints limiting agricultural productivity in the world. The effects of salt stress on growth, ions and organic solutes accumulation were investigated in two amaranth (Amaranthus cruentus) cultivars: Rouge (salt-resistant) and Locale (salt-sensitive). Young plants of these cultivars were exposed, in hydroponic system, to three concentrations of NaCl: 0, 30 and 90 mM. Growth parameters, ions, free proline and soluble sugars concentrations were determined after 2 weeks of stress. NaCl effect resulted in plant growth reduction in both cultivars but plants of cultivar Rouge were less affected compared to that of cv. Locale. Na+, proline and soluble sugars concentrations increased significantly in leaves and roots under salinity while K+, Ca2+ and Mg2+ concentrations decreased in both cultivars. Proline and soluble sugars increased significantly in leaves and roots of cultivar Locale whereas in cultivar Rouge, proline increase was significant only in roots and soluble sugars increase was significant only in leaves. The highest increase of Na+ concentration occurred in leaves of cv. Rouge coupled with the lowest reduction in K+ concentration. The highest increase of proline occurred in leaves of cultivar Locale whereas the highest increase of soluble sugars was observed in leaves of cultivar Rouge. The reduction of the Ca2+ concentration under salt stress was more accentuated in both leaves and roots of cultivar Rouge than cultivar Locale while cv. Rouge maintained higher content in Mg2+ either in leaves or in roots in the presence of NaCl than cultivar Locale. These results suggest an implication of Na+, K+ and Mg2+ in salt resistance in these cultivars and that soluble sugars may play an important role in salt-resistance in Amaranthus cruentus. However, proline appears as a symptom of injury in stressed plants rather than an indicator of resistance.

Susceptible and Glyphosate-Resistant Palmer Amaranth (<i>Amaranthus palmeri</i>) Response to Glyphosate Using C¹⁴as a Tracer: Retention, Uptake, and Translocation

The foliar retention, absorption, translocation, and diffusion of glyphosate in glyphosate resistant-(R) and susceptible (S)-Palmer amaranth populations from seed collected in Georgia in 2007 were examined. The R population of Palmer amaranth had an elevated copy number of the EPSPS gene conferring the mechanism of resistance. When applications of 14C-glyphosate to a single leaf followed entire plant treatment with glyphosate, the distribution percentages were similar for R and S for the above and below treated leaves when harvested at 1, 6, 12, 24, and 48 hours after treatment (HAT). There were initially no differences between R and S at 1 HAT with an average of 8% absorption for both biotypes. However, data indicated that glyphosate absorption increased for R-Palmer amaranth reaching 41% within 6 HAT and was significantly different (P = 0.01) from the 28% absorbed by S-Palmer amaranth. Glyphosate resistant and susceptible Palmer amaranth averaged 44% 14C-glyphosate absorption by 24 HAT. There were no differences for 14C-glyphosate Bq/mg of plant tissue between R and S for the above the treated leaf and below the treated leaf portions of plants at 1, 6, 12, 24, or 48 HAT. However, root accumulation of 14C-glyphosate in plant tissue was significantly greater by 12 HAT for the roots of R (1.21 Bq/mg) than for S (0.51 Bq/mg). The treated leaf of the R-Palmer amaranth plants exhibited greater translocation of 14C-glyphosate in Bq/mg of tissue than the susceptible over time, indicating no detrimental effect or cost of fitness due to EPSPS gene amplification. Additionally, there were no differences in glyphosate retention in leaf discs assays between R and S biotypes. In spite of an average of 6.5 Bq efflux out of R and S leaf discs after 15 minute, only 0.4 Bq was retained after 150 minutes. Glyphosate was not retained over time in the leaf discs for R and S, and there were no biotype differences within bathing times. However, the rate of efflux (the slope of the curves) was greater for the R biotype. These data support the reported gene amplification non-target site glyphosate resistance mechanism in Palmer amaranth.

<i>Amaranthus cordatus</i>as a Green Corrosion Inhibitor for Mild Steel in H₂SO₄and NaCl

This work studies the use of Amaranthus cordatus as the corrosion inhibitor for conventional mild steel in 0.5 M and 1.0 M of both H2SO4 and NaCl. The effects of different concentrations of the acid and base on the inhibition efficiency of Amaranthus cordatus were tested at room temperature and at different inhibitor volumes. The experiment was set for 30 days and weight-loss corrosion technique was employed in obtaining the corrosion penetration rate using the standard equation: . The result shows that the rates of corrosion of the mild steel increased with an increase in concentration of the acid or base and also decreased with increasing volume of Amaranthus cordatus. Expectedly, the inhibition efficiency was found to be greater in sodium chloride than in tetraoxosulphate VI acid. Also inhibition efficiency was found to increase with increase in extracts volume and decrease in concentration of the acid or base. These findings strongly suggest that Amaranthus cordatus can be used as the inhibitor for preventing the corrosion of mild steel.

Phytochemical Profiling with Antioxidant and Antimicrobial Screening of <i>Amaranthus viridis</i>L. Leaf and Seed Extracts

Methanol extracts of the dried leaves and seeds of Amaranthus viridis were collected and used for phytochemicals and antibacterial analysis. By detecting the MIC and zone inhibition, the antibacterial activity was determined against different bacterial and fungal strains. The extract yields from the leaves and seeds ranged 5.5-6.1 and 2.42%-3.72% w/w, respectively. Phytochemical investigation of this plant determines that tanins (6.07%-5.96%), saponins (53%-32%), alkaloids (13.14% - 11.42%), protiens (16.76%-24.51%) and glycosides (63.2%-32.3%) were rich in leaves. The extracts also contained appreciable levels of total phenolic contents (2.81-3.61 GAE, g/100 g), total flavanoid contents (18.4-5.42 QE, g/100 g) and DPPH free radical scavenging activity, showing IC50 (83.45-75.95 μg/mL) along with reducing power was calculated. The MIC of extracts ranged 178 - 645 μg/mL. The results of this study suggest the possibility of using the methanolic extracts in treating the diseases caused by the test organisms.

Female reproductive system of <i>Amaranthus</i>as the target for <i>Agrobacterium</i>-mediated transformation

Agrobacterium-mediated transformation through floral dip and rapid selection process after transgenic event had become a preference as it will overcome the difficulties faced in tissue culturing procedures and lengthy time for screening transformed progenies. Therefore, in this study, three constructs, p5b5 (14,289 bp), p5d9 (15,330 bp) and p5f7 (15,380 bp) in pDRB6b vector which has hygromycin as a selectable marker gene were introduced individually into Agrobacterium tumefaciens strain (AGL1). The cell suspension was applied to Amaranthus inflorescence by drop-by-drop technique and was left to produce seeds (T1). The T1 seeds were germinated and grown to produce seedlings under non-sterile condition. Hygromycin selection on seedling cotyledon leaves results in identification of 12 putative transformants, three from p5b5, four from p5d9 and five from p5f7. All positive putative transformants that were selected at the first stage through hygromycin spraying showed positive result in leaf disk hygromycin assay and in a construct specific polymerase chain reaction-based assay. A ~750 bp amplified hygromycin gene was further verified through sequencing. Our results suggest that Amaranthus inflorescences were able to be transformed and the transformed progenies could be verified through a combination of simple and rapid methods .

The Effect of Drought Occurring at Different Growth Stages on Productivity of Grain Amaranth Amaranthus cruentus G6

A greenhouse pot experiment was conducted to study the effect of drought induced at different phenological stages on growth, biomass production and yield performance of grain amaranth Amaranthus cruentus G6. After emergence seedlings were exposed to different soil water regimes： constant adequate moisture （W1） and drought （W2） throughout the growing period, drought initiated at crop inflorescence formation （W3）, drought condition during pre-inflorescence formation （W4） and treatment W5 where drought condition occurred in the period from the beginning of inflorescence formation to the beginning of flowering. Crop samples were taken at the maturity. The growth and yield performance of amaranth were assessed by measuring root length, stem height and inflorescence length, and by evaluating fresh and dry weight of plant parts, grain yield and harvest index. Drought stress initiated at different phenological stages affected the evaluated morphological parameters, assimilate allocation and grain yield. Drought throughout the growing period resulted in grain and biomass yield reduction for 51% and 50%, respectively. Water deficit during inflorescence formation appears to be critical growing stage influencing grain yield, while soil drying in the vegetative growth stages improve the assimilate allocation to the above-ground biomass and particularly to the grain.

The Synthesis of Gold Nanoparticles Using <i>Amaranthus spinosus</i>Leaf Extract and Study of Their Optical Properties

We report here the application of a medicinally important plant Amaranthus spinosus for the synthesis of gold nanoparticles (AuNPs). Different concentrations of ethanolic leaf extract of the plant were reacted with aqueous solution of HAuCl4·4H2O under mild reaction conditions. Synthesis of AuNPs was confirmed from the UV-Vis study of surface plasmon resonance property of the colloidal solution. Transmission electron microscopy (TEM) revealed particles as spherical and triangular in shape. X-ray diffraction (XRD) confirmed the crystalline nature of AuNPs with average size of 10.74 nm as determined by Debye-Scherrer’s Equation. Fourier transform infra-red (FT-IR) analysis of leaf extract and lyophilized AuNPs showed the presence of various functional groups present in diverse phytochemicals. Energy dispersive X-ray (EDX) of purified AuNPs confirmed the formation of AuNPs and surface adsorption of biomolecules. We further investigated the toxicity of the synthesized AuNPs and found non toxic to the cancer cell lines and could be used for biomedical applications.