Effects of common cocklebur control systems on soybean yields, costs, and returns

Common cocklebur (Xanthium pensylvanicum Wallr.) and other common weeds growing in soybean fields must be controlled in order to obtain maximum soybean yields. Many methods for achieving good weed control are available, however the cost and returns from these various systems are important, since partial weed control or even total control may or may not be economically favorable. The efficiency of weed control methods in soybeans should always be evaluated in conjunction with a detailed study of economic returns. Field studies were conducted in Tennessee during 1975 and 1976 under conventional tillage cropping at two locations, and during 1978 under no-tillage cropping at one location. These studies were conducted to determine: (1) the efficiency of various weed control systems for control of common cocklebur and other weeds, and (2) the effects of various levels of control of common cocklebur and other weeds on soybean yields, and the cost and returns from each level of control. In the conventional tillage experiments profluralin at 0.8 kg/ha was applied to the whole experimental area to control annual grasses and followed by sequential applications of pre and postemergence herbicides followed by between row cultivation to control cocklebur and other annual broadleaf weeds. Naptalam + dinoseb (Dyanap) at rate of 5.0 kg/ha was applied preemergence followed by postemergence applications at the second trifoliate stage of the soybeans of either bentazon at the rate of 0.8 kg/ha, or dinoseb at 0.8 kg/ha, or Dyanap at 2.5 kg/ha. These combinations were followed either by bentazon at 0.8 kg/ha or cultivation when the soybeans were 30-70cm tall, with other cultivations as needed later in the season. Also as separate treatments either linuron at 0.5 kg/ha or metribuzin at 0.6 kg/ha were applied at the preemergence stage or Dyanap at 4.2 kg/ha was applied at the cracking stage. None of these were followed by a postemergence treatment at the second trifoliate stage. These treatments were followed by either bentazon or cultivation when soybeans were 30-70cm tall plus other cultivation as needed later in the season. In the no-tillage experiment, glyphosate at 1.7 kg/ha was applied at planting over the whole experimental area. This was followed by metribuzin at 0.6 kg/ha and alachlor at 2.2 kg/ha applied preemergence singly or mixed to each plot. Thirty days later two new postemergence herbicides coded as RH-6201 at 2.2 kg/ha and HOE-29152 at 0.6 kg/ha, were applied singly or in combination over plots previously treated with the preemergence herbicides. Under conventional tillage all weed control methods increased yields, except Dyanap applied preemergence with no further treatment. Greatest soybean yields were produced with practices most effective for cocklebur control. The inclusion of the third treatment of bentazon or cultivation when the soybeans were 30-70cm tall followed by cultivation later in the season resulted in maximum yields. A postemergence treatment applied at second trifoliate stage of soybeans was not necessary if linuron was the preemergence treatment and bentazon was applied when soybeans were 30-70cm and followed by timely cultivation later in the season. A single post-emergence application of bentazon when the soybeans were 30-70cm tall followed by cultivation later in the season was enough to produce maximum yields, even when no prior treatment was made. (In all treatments profluralin had controlled the annual grasses.) The predicted adjusted yields ranged from 509-1748 kg/ha with 0% control of cocklebur to 2528-3161 kg/ha with 100% control. Total costs of production ranged from $142-167/ha with no cocklebur control to$207-228/ha with 100% control. An additional investment of $18-24/ha was required to increase common cocklebur control from 60 to 95Net returns were increased with all common cocklebur control measures, except where Dyanap was applied at either the preemergence or cracking stage without a subsequent treatment. Maximum net returns were obtained in all experiments when Dyanap was applied at the cracking stage and metribuzin was applied preemergence, if these treatments were followed by bentazon applied when the soybeans were 30-70cm tall and were cultivated later in the season. A single application of bentazon when the soybeans were 30-70cm tall, followed by cultivation later in the season with no prior treatments was enough to produce maximum net returns in each experiment, except at Ames Plantation in 1976. Bentazon applied when the soybeans were 30-70cm tall followed by cultivation later in the season contributed for maximum net returns when Dyanap was applied at the cracking stage, and when metribuzin was applied in preemergence. Failure to provide any control of common cocklebur resulted in net returns ranging from$-21 to $185/ha, according to the predicted regression equation developed to estimate the effects of these two variables. Control of 95$310 to $416/ha. According to these results the best cocklebur control systems for conventional tillage soybeans were: either Dyanap applied at the cracking stage or metribuzin applied preemergence, both followed by bentazon applied when the soybeans were 30-70cm tall followed by cultivation later in the season. Under no-tillage cropping none of the weed control measures tested significantly increased soybean yields or net returns when compared to the untreated control. This was partially due to poor soybean stands resulting from severe rabbit damage. Predicted adjusted yields of 509 kg/ha were calculated for 0% of weed control and 1547 kg/ha for 100-6 control. Maximum weed control was provided by all herbicide combinations that included metribuzin + RH-6201. These combinations provided an average of 90% weed control

Antitrypanosomal Activity of a Diterpene and Lignans Isolated from Aristolochia cymbifera

Bioguided fractionation of extract from the leaves of Aristolochia cymbifera led to the isolation of the furofuran lignans fargesin, epieudesmin, and sesamin; the dibenzylbutyrolactone lignans hinokinin and kusunokinin; and an ent-labdane diterpene named copalic acid. Our data demonstrated that copalic acid and kusunokinin were the most active compounds against trypomas-tigotes of Trypanosoma cruzi. Additionally, copalic acid demonstrated the highest parasite selectivity as a result of low toxicity to mammalian cells, despite a considerable hemolytic activity at higher concentrations. Among the isolated compounds, kusunokinin could be considered the most promising candidate, as it displayed significant activity against intracellular amastigotes (IC(50) = 17 mu M) and trypomastigotes (IC(50) = 51 mu M) without hemolytic activity. Fargesin, hinokinin, epieudesmin, and sesamin were also effective against trypomastigotes, but these compounds were highly toxic to mammalian cells and no parasite selectivity could be identified. the need for novel drugs for American trypanosomiasis is evident, and these secondary metabolites from A. cymbifera represent a useful tool for drug design.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09972270 Diadema São Paulo, BrazilInst Adolfo Lutz Registro, Dept Parasitol, Lab Toxinol Aplicada, São Paulo, BrazilInst Plantarum Estudos Flora, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09972270 Diadema São Paulo, BrazilFAPESP: 2008/11496-9CNPq: 473405/2008-3Web of Scienc

Brazilian flora extracts as source of novel antileishmanial and antifungal compounds

Natural products have long been providing important drug leads for infectious diseases. Leishmaniasis is a protozoan parasitic disease found mainly in developing countries, and it has toxic therapies with few alternatives. Fungal infections have been the main cause of death in immunocompromised patients and new drugs are urgently needed. In this work, a total of 16 plant species belonging to 11 families, selected on an ethnopharmacological basis, were analyzed in vitro against Leishmania (L.) chagasi, Leishmania (L.) amazonensis, Candida krusei, and C. parapsilosis. Of these plant species, seven showed antifungal activity against C. krusei, five showed antileishmanial activity against L. chagasi and four against L. amazonensis, among them species of genus Plectranthus. Our findings confirm the traditional therapeutic use of these plants in the treatment of infectious and inflammatory disorders and also offer insights into the isolation of active and novel drug prototypes, especially those used against neglected diseases as Leishmaniasis.Instituto Adolfo Lutz Serviço de Parasitologia Laboratório de Toxinologia AplicadaUniversidade Federal de São Paulo (UNIFESP) Departamento de Ciências Exatas e da TerraInstituto Plantarum de Estudos da FloraUNIFESP, Depto. de Ciências Exatas e da TerraSciEL

Anti-trypanosomal activity of 1,2,3,4,6-penta-O-galloyl-β -D-glucose isolated from Plectranthus barbatus Andrews (Lamiaceae)

MeOH extract from the leaves of Plectranthus barbatus Andrews (Lamiaceae), showed in vitro anti-trypanosomal activity. The bioassay-guided fractionation resulted in the isolation of a gallic acid derivative, identified as 1,2,3,4,6-penta-O-galloyl-β-D-glucose (PGG), after thorough NMR and MS spectral analysis. Finally, this compound was tested against trypomastigote forms of T. cruzi and displayed an EC50 value of 67 µM, at least 6.6-fold more effective than the standard drug benznidazole. This is the first occurrence of PGG in the Plectranthus genus and the first anti-parasitic activity described for PGG in the literature

Recent and local diversification of Central American understorey palms

Funder: Fondation Ernst et Lucie Schmidheiny; Id: http://dx.doi.org/10.13039/501100007636Funder: International Association for Plant Taxonomy; Id: http://dx.doi.org/10.13039/501100020652Funder: International Palm SocietyFunder: Swiss Systematics SocietyAbstract: Aim: Central America is largely covered by hyperdiverse, yet poorly understood, rain forests. Understorey palms are diverse components of these forests, but little is known about their historical assembly. It is not clear when palms in Central America reached present diversity levels and whether most species arrived from neighbouring regions or evolved locally. We addressed these questions using the most species‐rich American palm clades indicative of rain forests. We reconstructed and compared their phylogenomic and biogeographical history with the diversification of 54 other plant lineages, to gain a better understanding of the processes that shaped the assembly of Central American rain forests. Location: Central America. Time period: Cretaceous to present. Major taxa studied: Arecaceae: Arecoideae: Bactridinae, Chamaedoreeae, Geonomateae. Methods: We sampled 218 species through fieldwork and living collections. We sequenced their genomic DNA using target sequence‐capture procedures. Using 12 calibration points, we reconstructed dated phylogenies under three approaches (multispecies coalescent, maximum likelihood and Bayesian inference), conducted biogeographical analyses (dispersal–extinction–cladogenesis) and estimated phylogenetic diversity metrics. Results: Dated phylogenies revealed intense diversification in Central America from 12 Ma. Local diversification events were four times more frequent than dispersal events, and we found strong phylogenetic clustering in relationship to Central America. Main conclusions: Our results suggest that most understorey palm species that characterize the Central American rain forests today evolved locally after repeated dispersal events, mostly from South America. Understorey palms in Central American rain forests diversified primarily after closure of the Central American Seaway at c. 13 Ma, suggesting that the Great American Biotic Interchange was a major trigger for plant diversification in Central American rain forests. This recent diversification contrasts with the much earlier existence of rain forest palms in neighbouring South America since c. 58 Ma. We found similar timings of diversification in 54 other seed plant lineages, suggesting an unexpectedly recent assembly of the hyperdiverse Central American flora

Assessing the Chemical Composition and Antimicrobial Activity of Essential Oils from Brazilian Plants—Eremanthus erythropappus (Asteraceae), Plectrantuns barbatus, and P. amboinicus (Lamiaceae)

The chemical composition and antimicrobial activity of essential oils obtained from three Brazilian plant species—leaves and branches of Eremanthus erythropappus (Asteraceae), leaves of Plectranthus barbatus, and leaves of P. amboinicus (Lamiaceae)—were determined. Analysis by GC/MS and determination of Kovats indexes both indicated δ-elemene (leaves—42.61% and branches—23.41%) as well as (−)-α-bisabolol (leaves—24.80% and stem bark—66.16%) as major constituents of E. erythropappus essential oils. The main components of leaves of P. barbatus were identified as (Z)-caryophyllene (17.98%), germacrene D (17.35%), and viridiflorol (14.13%); whereas those of leaves of P. amboinicus were characterized as p-cymene (12.01%), γ-terpinene (14.74%), carvacrol (37.70%), and (Z)-caryophyllene (14.07%). The antimicrobial activity against yeasts and bacteria was assessed in broth microdilution assays to determine the minimum inhibitory concentration (MIC) necessary to inhibit microbial growth. In addition, the crude oil of branches of E. erythropappus was subjected to chromatographic separation procedures to afford purified (−)-α-bisabolol. This compound displayed biological activity against pathogenic yeasts, thus suggesting that the antimicrobial effect observed with crude oils of E. erythropappus leaves and branches may be related to the occurrence of (−)-α-bisabolol as their main component. Our results showed that crude oils of Brazilian plants, specifically E. erythropappus, P. barbatus, and P. amboinicus and its components, could be used as a tool for the developing novel and more efficacious antimicrobial agents

Nos caminhos da história urbana, a presença das figueiras-bravas

RESUMO Este texto trata das chamadas figueiras-bravas, espécies nativas em florestas tropicais e subtropicais que, plantadas ou nascendo espontaneamente em certos locais, propiciaram, sob suas imensas copas, espaços de sociabilidade em muitos núcleos urbanos oitocentistas. As figueiras-bravas foram também importantes marcos paisagísticos, influindo muitas vezes na configuração de espaços urbanos de várias cidades brasileiras. Neste artigo, três casos relativos ao estado de São Paulo são apresentados: o caso de Lorena, no Vale do Paraíba, onde ao menos quatro logradouros importantes foram formados a partir da existência de figueiras-bravas e outros dois casos relativos à capital paulista, a saber, a figueira-brava da chácara da Marquesa de Santos, na várzea do Carmo, atual Parque D. Pedro II, e a figueira conhecida como Árvore das Lágrimas, ainda existente no Ipiranga