Asif Tanveer

Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities.

ETHNO-PHARMACOLOGICAL RELEVANCE Cyperus rotundus L. (Cyperaceae) is a medicinal herb traditionally used to treat various clinical conditions at home such as diarrhea, diabetes, pyresis, inflammation, malaria, and stomach and bowel disorders. Currently, it is one of the most widespread, problematic, and economically damaging agronomic weeds, growing wildly in various tropical and subtropical regions of the world. The present paper summarizes the available information that will aid in future medicine preparation by identifying active ingredients and their mode of action for a specific therapeutic activity using the latest technologies. MATERIAL AND METHOD This review article is based on the information available on the phytochemical, toxicological, and pharmacological studies on and traditional uses of C. rotundus. The present paper covers the literature available particularly from 2000 to 2015 online (Google Scholar, PubMed, ScienceDirect, Scopus, SpringerLink, and Web of Science) and in books on phytochemistry, ethnopharmacology, and botany of this plant. RESULTS Phytochemical and pharmacological studies revealed the significance of C. rotundus as an antiandrogenic, antibacterial, anticancerous, anticonvulsant, antidiabetic, antidiarrheal, antigenotoxic, anti-inflammatory, antilipidemic, antimalarial, antimutagenic, antiobesity, antioxidant, anti-uropathogenic, hepatoprotective, cardioprotective, neuroprotective, and nootropic agent. This is the most investigated plant worldwide due to the higher concentration of active ingredients in the form of essential oils, phenolic acids, ascorbic acids, and flavonoids in the tuber and rhizomes. Unfortunately, this significant plant species has not been assessed under improved cultivation conditions with the aim of conservation in natural habitats and high quality. CONCLUSION Reports can be found on the ehtnobotanical use of C. rotundus in atherosclerosis, aging, apoptosis, cancer, cystitis, epilepsy, hirsutism, nociception, prostatitis, and genotoxicity disorders. The phytochemical and pharmacological activities of C. rotundus have supported its traditional as well as prospective uses as a valuable Ayurvedic plant. Previous researches focuses on the phytochemistry, biological properties and clinical application of rhizomes and tubers of C. rotundus. However, such studies on the other parts of this medicinally important plant are still quest to be investigate. Furthermore, future study should aim at confirming the clinical activities and safety of this plant before being used for the development of new therapeutic agent in human subjects.

Methods to Break Seed Dormancy of Rhynchosia capitata, a Summer Annual Weed

La dormancia seminal de las malezas es un rasgo significativo contribuyente a su tasa de supervivencia, puesto que ayuda a las malezas a evitar herbicidas y otras practicas de desmalezado junto con condiciones ambientales desfavorables. Investigamos los efectos de diferentes tratamientos para romper dormancia sobre la germinacion de Rhynchosia capitata, una maleza anual estival comun en Paquistan. Las semillas se sumergieron en tiourea, KNO3, HCl, HNO3 y H2SO4 y ademas fueron escarificadas mecanicamente (papel lija). Los resultados indicaron que las semillas de R. capitata muestran signos de dormancia fisica principalmente debido a impermeabilidad de su cubierta. Escarificacion mecanica y acida (inmersion de semillas en H2SO4 por 60 y 80 min y en HCl por 12 y 15 h) fueron muy eficientes para romper dormancia y promover germinacion. Las semillas sumergidas en HNO3 por 1 a 5 dias mostraron poco efecto, mientras diversas concentraciones de tiourea y KNO3 fueron inefectivas para romper dormancia seminal en R. capitata.

Influence of seed size and ecological factors on the germination and emergence of field bindweed (Convolvulus arvensis)

An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 oC, with optimum germination between 20 and 25 oC. Time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased with an increase in temperature from 20 oC, salinity and osmotic stress. However, germination was tolerant to low salt (25 mM) or osmotic stress (0.2 MPa), but as salinity and osmotic stress increased, germination percentage and germination index decreased. Seeds of C. arvensis placed at soil surface showed maximum emergence and decreased as seeding depth increased. Seeds of C. arvensis germinated over a wide range of pH (4 to 9) but optimum germination occurred at pH 6 to 8. Under highly alkaline and acidic pH, time to start germination, time to 50% germination and mean germination time increased while germination percentage and germination index decreased. Increase in field capacity caused decreased time to start germination, time to 50% germination and mean germination time but increased germination percentage and germination index. Bigger seeds had low time to start germination, time to 50% germination and mean germination time but high germination percentage and germination index. Smaller seeds were more sensitive to environmental factors as compared to larger or medium seeds. It can be concluded that except for pH, all environmental factors and seed sizes adversely affect C. arvensis as regards seed germination or emergence and germination or emergence traits, and larger seeds result in improved stand establishment and faster germination than small seeds, regardless of moisture stress or deeper seeding depth.

Reduced Doses of a Sulfonylurea Herbicide for Weed Management in Wheat Fields of Punjab, Pakistan

Reduction in herbicide usage without compromising yields can lead to less environmental harm and lower production costs. Field trials were conducted to appraise the efficacy of reduced doses (25, 50, and 75% of the label dose) of a post emergence sulfonylurea herbicide [Atlantis 3.6WG (iodo+mesosulfuron)] to control weeds in wheat (Triticum aestivum L.) fields of Punjab, Pakistan. Below-labeled-doses were quite effective in suppressing total weed density (72-95%) and biomass (8394%), and wheat grain yield was increased by 22 to 48% over the weedy control, while label dose of iodo+mesosulfuron improved yield by 53%. Iodo+mesosulfuron at 25 and 50% of the label dose inhibited grass weeds by 43 to 64%, albeit their biomass was suppressed by > 80% over control. Wheat yields for reduced herbicide doses (50 and 75%) were not different with label dose. Economic analysis revealed that the maximum marginal rate of return was recorded for 50% of the label herbicide dose and was followed by that observed for 25% of the label dose. Reduced doses of herbicide can be an effective tool in minimizing herbicide inputs and lowering production costs in wheat production without compromising yields.

Allelopathic effects of aqueous and organic fractions of Euphorbia dracunculoides Lam. on germination and seedling growth of chickpea and wheat

Se requiere la identificacion de especies de malezas con potencial alelopatico y la caracterizacion de sus efectos adversos en contra de los cultivos asociados para una mejor comprension de las interacciones cultivos-malezas. Se investigo la actividad fitotoxica de Euphorbia dracunculoides Lam. en la germinacion y crecimiento de plantulas de garbanzo (Cicer arietinum L.) y trigo (Triticum aestivum L.) bajo condiciones controladas. Dos estudios separados se realizaron con cada una de las cuatro fracciones de disolventes organicos (n-hexano, cloroformo, acetato de etilo, 1-butanol) y extracto acuoso (1:10 y 1:20) de fracciones enteras de plantas de E. dracunculoides usando agua destilada y 0,05% (v/v) dimetil sulfoxido (DMSO) como control. Diferentes fracciones acuosas y organicas de E. dracunculoides tuvieron una incidencia significativa en los atributos de germinacion y crecimiento de las plantulas de las especies evaluadas. El porcentaje de germinacion final de trigo no se vio afectado, sin embargo, la elongacion de raices y brotes y la acumulacion de biomasa en estas partes fueron significativamente retrasadas. La fraccion acuosa fue mas itotoxica que las fracciones organicas y disminuyo la germinacion de garbanzo en 53% y 35% para 1:10 y 1:20, respectivamente. Estas fracciones acuosas, 1:10 y 1:20, tambien redujeron la longitud de raices (75-64% y 33-34%) y brotes (62-18% y 21-21%) y el peso seco de raices (32-33% y 42-46%) y brotes (32-7% y 8480%) para trigo y garbanzo, respectivamente. Entre las fracciones organicas, n-hexano fue la mas supresora de las especies ensayadas. El analisis cromatograico detecto la presencia de cuatro itotoxinas en la fraccion acuosa (1:10) de la planta: acido furoico, acido p-cumarico, acido cafeico, y acido siringico. El estudio determino que E. dracunculoides es alelopatica sobre el trigo y el garbanzo.

Glyphosate hormesis in broad-leaved weeds: a challenge for weed management

ABSTRACT Little is known of glyphosate-induced hormesis in weeds and how this might influence weed management. To test the hormetic effect of low doses of glyphosate on broad-leaved weeds, two experiments were conducted, in the laboratory and the screenhouse. The hormetic effects of glyphosate solution in growth media (0, 65, 130, 250, and 500 g acid equivalent (a.e) ha−1) and foliar spray (0, 4, 8, 16, 32, and 64 g a.e. ha−1) were tested on four broad-leaved weeds (Coronopus didymus, Chenopodium album, Rumex dentatus, and Lathyrus aphaca). Glyphosate solution in the range 65–250 g a.e. ha−1 stimulated the germination and seedling growth of all tested weeds. However, at 500 g a.e. ha−1 inhibition of germination and growth was observed. Foliarly applied glyphosate in the range 4–32 g a.e. ha−1 increased root and shoot length, dry biomass, and seed production ability of all four weeds species; however, the stimulatory response was species dependent. These results indicate that glyphosate hormesis could play a significant role in altering crop/weed competition and might influence weed management.

Effect of weed-crop competition on growth and yield of garden cress (Lepidium sativum L.)

A field experiment to evaluate the effect of weed-crop competition duration i.e. Zero competition and competition for 40, 50, 60, 70 and 80 days after emergence and throughout the growing season on the growth of weeds and yield of Lepidium sativum L. was conducted during 2005-06 at the Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan. The dominant weeds were Phalaris minor, Anagallis arvensis, Chenopodium album, Convolvulus arvensis and Medicago denticulata. Maximum density and dry weight of weeds were recorded in plots with competition throughout the season and the minimum was observed in weed-crop competition for 40 days after emergence. Maximum seed yield was recorded in plots where weeds were not allowed to grow throughout the growing season. The increase in yield was mainly due to greater plant height, branches and seeds per plant. The minimum seed yield was recorded in plots where weeds were allowed to compete with the crop throughout the growth period of the crop. For obtaining higher yield of garden cress it is suggested to control weeds before 40 days after emergence.

Differential suppression of rice weeds by allelopathic plant aqueous extracts

Herbicidal potential of different plant aqueous extracts was evaluated against early seedling growth of rice weeds in pot studies. Plant aqueous extracts of sorghum (Sorghum bicolor), sunflower (Helianthus annuus), brassica (Brassica compestris), mulberry (Morris alba), eucalyptus (Eucalyptus camaldunensis), and winter cherry (Withania somnifera) at a spray volume of 18 L ha-1 each at the 2-4 leaf stage of rice weeds viz horse purslane (Trianthema portulacastrum) [broad-leaf], jungle rice (Echinochloa colona), and E. crus-galli (barnyard grass) [grasses] and purple nut sedge (Cyperus rotundus) and rice flat sedge (C. iria) [sedges]. The results showed significant interactive effects between plant aqueous extracts and the tested weed species for seedling growth attributes depicting that allelopathic inhibition was species-specific. Shoot and root length, lateral plant spread, biomass accumulation, and leaf chlorophyll contents in test species were all reduced by different extracts. The study suggested the suppressive potential of allelopathic plant aqueous extracts against rice weeds, and offered promise for their usefulness as a tool for weed management under field conditions.

Allelopathy in agro-ecosystems: a critical review of wheat allelopathy-concepts and implications

Allelopathy is an important mechanism of plant interference mediated by the release of plant-produced secondary metabolites or decomposition products of microbes to the aerial or soil environment. It plays a key role in natural as well as cultivated ecosystems. Allelochemicals are released into the soil rhizosphere by a variety of mechanisms, including volatilization, decomposition of residues, and root exudation. Along with inhibitory/stimulatory effects of allelochemicals, several other ecological roles of these chemicals, including plant defense, nutrient chelation, and regulation of soil biota, have been reported. Wheat is extensively studied and used as an allelopathic crop, and numerous chemicals are reported to be released from the wheat living plants and decomposing residues. In this review, we presented a contemporary synthesis of the existing data that how wheat allelopathy can be exploited: (a) to biologically control the insects, pests, and diseases, (b) to enhance the soil quality by adding nutrients for crop plants during decomposition from residues and ameliorate soil environment for microbes, (c) to increase the crop diversification by rotation while reducing the weeds and pests infestation, (d) to develop the low-cost biological pesticides with a novel mode of action from crop plants, and (e) to confer tolerance against abiotic stresses. Based on our hypothetical concepts and previous evidences, we briefly discussed the mode of action of allelochemicals, and extent and rate of their production based on crop growth stage. We also addressed the interaction of root exudates and allelochemicals with soil biotic and abiotic components to explore the role of allelopathy in rhizosphere ecology.

Comparative allelopathic potential of metabolites of two Alternanthera species against germination and seedling growth of rice

A laboratory study was conducted to investigate the allelopathic effect of aqueous extracts of plant parts of Alternanthera philoxeroides and A. sessilis and soil incorporated residues on germination and seedling growth of rice (Oryza sativa). Aqueous extracts prepared from different plant parts of Alternanthera species delayed rice germination. Alternanthera philoxeroides and A. sessilis inhibited rice germination by 9-100% and 4-49%, respectively. Germination of rice seeds was reduced with increasing concentration of aqueous leaf extracts of both weed species. Early seedling growth (root and shoot lengths) and seedling vigor index were significantly reduced by 5% aqueous leaf extract compared with distilled water treated control. Germination, root and shoot lengths, root and shoot dry weights and seedling vigor index of rice were drastically reduced by 3 and 4% in residue infested soil compared with residue free soil. The inhibitory effect of A. philoxeroides in terms of germination and seedling growth of rice was greater than that of A. sessilis. Five percent aqueous leaf extract and 4% residue infested soil of A. philoxeroides caused complete failure of rice seed germination. Alternanthera philoxeroides contained water soluble phenolics, namely 4 hydroxy-3-methoxy benzoic acid (16.19 mg L-1) and m-coumaric acid (1.48 mg L-1), whereas Alternanthera sessilis was rich in chlorogenic acid (17.85 mg L-1), gallic acid (11.03 mg L-1) and vanillic acid (9.88 mg L-1). The study indicates that the allelopathic potential of Alternanthera species may play an important role in enhancing the invasiveness of these species and may suppress rice plants in the vicinity.