antibacterial activity of the aerial extracts from xanthium brasilicum prepared in methanol, diethyl ether, petroleum benzene and an equal mixture of the three solvents were studied against bacterial laboratory standards and clinical isolates using the disk diffusion method. the best antibacterial results were obtained when methanol or the solvent mixture was used. the crude extract with the hi...

Vegetative plants of Xanthium strumarium L. grown in long days were induced to flower by exposure to one or several 16-hour dark periods. The distribution of male and female inflorescences on the flowering shoot was described, and a scoring system was designed to assess the development of the female inflorescences. The time of movement of the floral stimulus out of the induced leaf and the timi...

in order to study the weeds frequency and dry matter in corn and cowpea sole cropping and intercropping systems, an experiment using replacement and additive techniques was conducted using different combination of intercropping in seven levels with ratio of 1:1 (50% corn + 50% cowpea), 1:2 (33% + 67%), 2:1 (67% + 33%), (100% + 20%), (100% + 10%), 100% corn and 100% cowpea, two levels optimal an...

The leaves of the Xanthium spinosum plant have been used culturally in Paraguay for their medicinal properties. Acute toxicity of mature leaf extract was evaluated. For the study, 35 Balb/c mice were selected and allocated into 7 groups, 6 test groups and 1 control group. The extract was prepared in concentrations of 6% and 9% (g/dL). The 6% concentration was administrated to 3 test groups and ...

Four new glycosides, namely 3β-norpinan-2-one 3-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (1), (6Z)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-glucopyranoside (2), (6E)-3-hydroxymethyl-7-methylocta-1,6-dien-3-ol 8-O-β-d-gluco-pyranoside (3), and 7-[(β-d-apiofuranosyl-(1→6)-β-d-glucopyranosyl)oxymethy]-8,8-dimethyl-4,8-dihydrobenzo[1,4]thiazine-3,5-dione (4), were isolated from the f...

Fluorescence and thermal imaging were used to examine the dynamics of stomatal patches for a single surface of Xanthium strumarium L. leaves following a decrease in ambient humidity. Patches were not observed in all experiments, and in many experiments the patches were shortlived. In some experiments, however, patches persisted for many hours and showed complex temporal and spatial patterns. Ra...

Leaf resistance for water vapor (total diffusion resistance minus boundary layer resistance), transpiration, and leaf temperature were measured in attached leaves of greenhouse-grown Xanthium strumarium L. plants that had been pretreated for 72 hours with high (40 C day, 35 C night), or low (10 C day, 5 C night) air temperatures. Measurements were made in a wind tunnel at light intensity of 1.1...

Leaf gas exchange, temperature, and incident radiation were measured in situ for 20 mature trees of 12 deciduous species spanning a range of heights from 7.9 to 30.1 m and growing in the southern Appalachian Mountains. Air temperature, water vapor pressure, total radiation, photosynthetically active radiation, and carbon dioxide concentration were also measured. Estimated mean, light-saturated ...