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Allelopathy of Rice Husk on Barnyardgrass  [PDF]
Jonghan Ko,Seok Hyun Eom,Myong Jo Kim,Chang Yeon Yu
Journal of Agronomy , 2005,
Abstract: Research efforts in seeking allelopathic compounds play an important role in developing natural herbicides. The objective of this research was to investigate the allelopathic effects of rice (Oryza sativa L.) husk extracts and to bioassay allelopathic compounds. The husk extracts of seven rice varieties were used to examine allelopathic effects on the growth of barnyardgrass (Echinochloa crusgalli (L.) Beauv.). After that, allelopathic substances effective on the growth of barnyardgrass were sought using an open chromatography and analyzed using a GC/MS. Husk extract from Ilpum rice (a national variety in South Korea) showed the prominent allelopathic effect on barnyardgrass. The organic compounds analyzed by the GC/MS were found to be 9-octadecenoic acid; 7-octadecenoic acid; 5, 8, 11-heptadecatriynoic acid and androstan-17-one. The minimum inhibition concentration of the isolated allelochemical compounds was 50 ppm. The results suggest that there is a possibility of developing a rice husk oriented natural herbicide effective on barnyardgrass.
Inhibitory effects of Acorus tatarinowii on algae growth
石菖蒲(Acorus tatarinowii)克藻效应的研究

HE Chiquan,YE Juxin,

生态学报 , 1999,
Abstract: The inhibitory effect of Acorus tatarinowii on algae growth was studied,in addition to the competitions of light and minerial nutrients between Acorus tatarinowii and algae,the machanism of this inhibitory effect is mainly due to the excretion of some organic substances from the root system and rhizome of Acorus tatarinowii which may injure and abate the algae cells(Allelopathic effect) When the algal cells were treated with cultured water of Acorus tatarinowii ,chlorophyll a was found to be...
Allelopathic effect of Acorus tatarinowii upon algae
Allelopatrhic effect of Acorus tatarinowii upon algae

HE Chi-quan,WANG Chang-ke,
HE Chi-quan
,WANG Chang-ke

环境科学学报(英文版) , 2001,
Abstract: Besides competing with algae for light and mineral nutrients (i.e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in "A. tatarinowii water", some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTC) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A. tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 microliters/disc, the inhibitory rate was negative; if it was over 45 microliters/disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 microliters/disc and 45 microliters/disc.
Eclipta alba: A Phytopharmacognostic Study  [PDF]
Kadam Prasad V.,Yadav Kavita N.,Navasare Vidya S.,Bhilwade Sumeet K.
International Journal of Pharmaceutical and Phytopharmacological Research , 2012,
Abstract: Pharmacognostic studies of crude drug plays a very important role in identification of the purity and quality of crude drugs. Medicinal plants which are found on earth have renowned medicinal significance and their usage is increasing day by day in our daily life. Different researches are going on to explore the pharmacological and medicinal properties of herbal drugs. The herb of Eclipta alba is commonly called as Bhringaraja or Maka, belonging to the family Asteraceae/Compositae. The present work embodies the investigations carried out to establish methods for quality control of herb as per WHO guidelines. Complete botanical evaluation which comprises macroscopic, microscopic, phytochemical evaluation and physicochemical parameters like loss on drying extractive value, ash value. The study will provide referential information for the correct identification of the crude drug.
Rice and Barnyardgrass: Water Stress and Initial Establishment  [PDF]
José Maria Barbat Parfitt, André Andres, Germani Concen?o, Gustavo Mack Teló, Fábio Schreiber, Jaqueline Trombetta da Silva, Ivana Santos Moisinho, Pamela Andrades Timm
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.812210
Abstract: The present work aimed to evaluate the effect of different water stress levels on the development of both rice and barnyardgrass. The study was established into greenhouse, in completely randomized design, in factorial scheme 2 × 5, with four replications. Factor “A” comprised the plant species (rice cv. BRS Querência, or the weed Echinochloa crusgalli), and factor “B” comprised the water stress levels: (T1) continuous flood (CF); (T2) 0 kPa (saturated soil); (T3) 10 kPa; (T4) 40 kPa; and (T5) 100 kPa. Plant emergence was assessed every day; plant length was measured 30 days after planting. At the end of the experiment, the number of leaves per plant, root length and shoot and root dry mass were determined. Our data supply evidence that under moderate water stress, up to approximately 40 kPa, rice tends to perform better than barnyardgrass in the initial stage of crop growth, when under equivalent plant density. However, barnyardgrass is usually present in much higher plant density than crop plants in fields traditionally cropped with rice. Thus, efficient control of barnyardgrass should be accomplished to avoid damage to rice crop by competition for environmental resources.

YE Ju,Xin HE Chi,Quan,and CHEN Shao,Feng,

植物生态学报 , 1999,
Abstract: An inhibitory effect of Acorus tatarinowii on algae growth was found.In addition to the competitions of light and mineral nutrients between Acorus tatrinowii and algae,the mechanism of this inhibitory effect was mainly due to an excretion of some organic substances from the root system and rhizome of Acorus tatarinowii which may injure and abate algal cells(allelopathic effect). When algal cells were treated with cultured water of Acorus tatarinowii, chlorophylla was destroyed,the photosynthetic rate of algae markedly declined and the ability of cells to reduce TTC decreased.Under fluorescence microscope,it was seen that algal cells turned from bright red to bluish green.
Sangeeta Raut, Smita Raut and Alekha Ghadai
International Journal of Microbiology Research , 2012,
Abstract: Since plants are used as therapeutic agents, the present study was conducted to evaluate the phytochemical profile and antibacterial activities of extracts of. Eclipta alba and Tylophora indica .Studies on the antibacterial activity of methanol, petroleum ether and aqueous extracts of dry leaf, stem and root of Eclipta alba and Tylophora indica was evaluated using zone of inhibition studies and minimum inhibitory concentration. The microorganisms used include Escherichia coli, Micrococcus roseus and Pseudomonas flavescens . The extract exhibited antibacterial activity against these experimental strains. Methanol extracts shows higher degree of antibacterial activity than aqueous and petroleum ether extracts. The minimum inhibitory concentration ranged between 12.5mg/mL and 75mg/mL depending on microorganism and various extract. Screening of the phytochemical extracts revealed the presence of compounds like alkaloids, glycosides, tannins and flavonoids. Escherichia coli and Pseudomonas flavescens are more sensitive where as Micrococcus roseus is less sensitive to extracts of Eclipta alba and Tylophora indica. The experimental observation shows that Eclipta alba and Tylophora indica have antibacterial activity and can be used for therapeutic purposes.
Separation of Allelopathy from Resource Competition Using Rice/Barnyardgrass Mixed-Cultures  [PDF]
Hai Bin He, Hai Bin Wang, Chang Xun Fang, Zhi Hua Lin, Zheng Ming Yu, Wen Xiong Lin
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037201
Abstract: Plant-plant interference is the combined effect of allelopathy, resource competition, and many other factors. Separating allelopathy from resource competition is almost impossible in natural systems but it is important to evaluate the relative contribution of each of the two mechanisms on plant interference. Research on allelopathy in natural and cultivated plant communities has been hindered in the absence of a reliable method that can separate allelopathic effect from resource competition. In this paper, the interactions between allelopathic rice accession PI312777, non-allelopathic rice accession Lemont and barnyardgrass were explored respectively by using a target (rice)-neighbor (barnyardgrass) mixed-culture in hydroponic system. The relative competitive intensity (RCI), the relative neighbor effect (RNE) and the competitive ratio (CR) were used to quantify the intensity of competition between each of the two different potentially allelopathic rice accessions and barnyardgrass. Use of hydroponic culture system enabled us to exclude any uncontrolled factors that might operate in the soil and we were able to separate allelopathy from resource competition between each rice accession and barnyardgrass. The RCI and RNE values showed that the plant-plant interaction was positive (facilitation) for PI312777 but that was negative (competition) for Lemont and barnyardgrass in rice/barnyardgrass mixed-cultures. The CR values showed that one PI312777 plant was more competitive than 2 barnyardgrass plants. The allelopathic effects of PI312777 were much more intense than the resource competition in rice/barnyardgrass mixed cultures. The reverse was true for Lemont. These results demonstrate that the allelopathic effect of PI312777 was predominant in rice/barnyardgrass mixed-cultures. The most significant result of our study is the discovery of an experimental design, target-neighbor mixed-culture in combination with competition indices, can successfully separate allelopathic effects from competition.
Manik Sharma,Muhammad Yusuf,Showkat Hussain,Abrar Hussain
International Research Journal of Pharmacy , 2012,
Abstract: Eclipta alba (L.) Hassk commonly known as bhringraj. It is mainly found spreading easily in moist grounds and is widely used for its nutritional values all over the world. The plant is used to treat different diseases in human in traditional medicine. The important pharmacological activities are hepatoprotection, antibacterial, analgesic, antidiabetic hair growth, etc. This paper explains the evidence- based information regarding the photochemistry and pharmacological activity of this plant.
Effect of dose and application site on quinclorac absorption by barnyardgrass biotypes
Concen?o, G.;Silva, A.F.;Ferreira, E.A.;Galon, L.;Noldin, J.A.;Aspiazú, I.;Ferreira, F.A.;Silva, A.A.;
Planta Daninha , 2009, DOI: 10.1590/S0100-83582009000300015
Abstract: this work aimed to evaluate the uptake and translocation of quinclorac in function of application sites (shoot or roots) by echinochloa crusgalli biotypes resistant and susceptible to this herbicide. the treatments consisted of quinclorac doses (0; 0.5; 1; 2; 4; 16 and 64 ppm), applied on the shoot or roots of seedlings of barnyardgrass biotypes. the experimental units consisted of plastic cups containing 250 cm3 of sand. the treatments were applied 10 days after emergence, when barnyardgrass plants reached a 2- to 3- leaf growth stage. the barnyardgrass biotypes were irrigated with nutritive solution weekly and maintained for 40 days after emergence, when length, fresh and dry matter of shoot and roots were evaluated. variance analysis was carried out using the f test at 5% probability, and in case of significance, a non-linear regression analysis was also carried out using a three-parameter logistic model. in the susceptible biotype, quinclorac was more absorbed by the roots than by the shoot. comparing dry mass production of the different plant parts of the susceptible biotype per application site, it was verified that quinclorac action is higher when applied to the plant roots. however, for the resistant biotype, it was not possible to determine the dose causing 50% reduction in dry mass accumulation (gr50) and in the resistance index (ri) between both biotypes, due to its high resistance to quinclorac (128 times the recommended dosage). the results showed that quinclorac resistance by the evaluated biotype is not due to differences in the absorption site, strongly suggesting that the resistance acquired by the biotype may result from alteration in the target site.
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