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PubMed1969

Iron content and ferritin in leaves of iron treated Xanthium pensylvanicum plants.

Iron administration to iron-starved cocklebur (Xanthium pensylvanicum) plants causes an increase in the iron content of ferritin fractions extracted from mature leaves. Xanthium plants grown under long days (vegetative stage) have more iron and ferritin than similarly iron-treated plants induced to flower under short day regimes. This first demonstration of ferritin in cocklebur (Compositae) leaves suggests that a substantial portion of iron that enters the iron-starved plant appears as this protein-iron macromolecule.

Ferritins↗
PubMed1977

Translocation patterns in xanthium in relation to long day inhibition of flowering.

The nature of long day inhibition of flowering in the short day plant Xanthium strumarium L. was studied by correlating the flowering response with the translocation of (14)C-assimilates from induced leaves or parts thereof to the shoot tips.In contrast to an earlier study by Gibby and Salisbury (Plant Physiol 1971 47: 784-789) no inhibitory effect of an immature leaf in long day on the flower-promoting effect of an induced leaf was detected. When the stimulus moved in the basipetal direction, mature leaves in long day were inhibitory to flowering and at the same time reduced the amount of (14)C-photosynthate that accumulated in the receptor buds.Inhibition of flowering was observed when the apical half of a single leaf was induced and the basal half kept under long day conditions. Induction of a lateral leaf half, with the other half remaining in long day, resulted in a normal flowering response. More (14)C-photosynthate was translocated to the shoot tip from the basal than from the apical leaf half.Removal of the noninduced basal leaf half except for the midrib and major veins, cutting the basal half along the midrib, or keeping the basal half in darkness, resulted in normal flowering. In all three treatments the amounts of (14)C-assimilates that accumulated in the shoot tips also increased, presumably because competing export of nonlabeled assimilates from the basal leaf halves was diminished or eliminated.Autoradiography indicated that (14)C-assimilates produced in the apical half were channeled through the basal half in the major veins and midrib to the petiole without partitioning back into the mesophyll. Since the veins and midrib in the basal half were by themselves not inhibitory to flowering, it is unlikely that the floral stimulus was inactivated in the long day tissue. When the basal half was labeled with (14)CO(2), there was no indication in autoradiograms that (14)C-labeled assimilates moved in the blade in the apical direction.As a whole these results demonstrate that transmission of the floral stimulus and translocation of photosynthate are correlated, so that at least part of the long day inhibition in Xanthium can be explained in terms of translocation effects. However, the involvement of a transmissible inhibitor produced in long day tissue cannot be ruled out.

Journal Article↗
PubMed1978

Does the Induction of Flowering by Photoperiod Change the Polarity or Other Characteristics of Indole-3-acetic Acid Transport in Petioles for the Short Day Plant, Xanthium?

To test the hypothesis that photoinduction acts by changing the ability of the plant to transport hormones, rather than by changing the ability of organs to synthesize them, the transport of carboxy-labeled indole-3-acetic acid was measured in the short day plant Xanthium pensylvanicum. Plants grown under noninductive conditions were matched for developmental stage, then assigned by a mathematically random method to either short day or noninductive conditions of "short day + light break." After the plants had been subjected to one to seven cycles, the movement of auxin was followed through sections cut from the middle of petioles of various ages. Photoinduction, even with as many as seven cycles, had no effect on auxin movement in either the basipetal or acropetal direction. Auxin movement in vegetative Xanthium was similar to that in Coleus and Phaseolus: strongly polar in a basipetal direction through younger petioles, but with polarity declining with increasing petiole age and concomitant decreasing elongation.

Journal Article↗
PubMed1980

Changes in the Levels of Abscisic Acid and Its Metabolites in Excised Leaf Blades of Xanthium strumarium during and after Water Stress.

The time course of abscisic acid (ABA) accumulation during water stress and of degradation following rehydration was investigated by analyzing the levels of ABA and its metabolites phaseic acid (PA) and alkalihydrolyzable conjugated ABA in excised leaf blades of Xanthium strumarium. Initial purification was by reverse-phase, preparative, high performance liquid chromatography (HPLC) which did not require prior partitioning. ABA and PA were purified further by analytical HPLC with a muBondapak-NH(2) column, and quantified by GLC with an electron capture detector.The ABA content of stressed leaves increased for 4 to 5 hours and then leveled off due to a balance between synthesis and degradation. Since PA accumulated at a constant rate throughout the wilting period, it was concluded that the rate of ABA synthesis decreased after the first 4 to 5 hours stress. Conjugated ABA increased at a low rate during stress. This is interpreted to indicate that free ABA was converted to the conjugated form, rather than the reverse.Following rehydration of wilted leaves, the ABA level immediately ceased increasing; it remained constant for 1 hour and then declined rapidly to the prestress level over a 2- to 3-hour period with a concomitant rise in the PA level. In contrast to the rapid disappearance of ABA after relief of stress, the high PA content of rehydrated leaves declined only slowly. The level of conjugated ABA did not change following rehydration, indicating that conjugation of ABA was irreversible.Detached Xanthium leaves that were subjected to a wilting-recovery-rewilting cycle in darkness, responded to the second wilting period by formation of the same amount of ABA as accumulated after the first stress period.

Journal Article↗
PubMed1981

Twilight effect: initiating dark measurement in photoperiodism of xanthium.

Six experiments studied the effects of low levels of red and far-red light upon the initiation of measurement of the dark period in the photoperiodic induction of flowering in Xanthium strumarium L. (cocklebur), a short-day plant, and compared effects with those of comparable light treatments applied for 2 hours during the middle of a 16-hour inductive dark period. Red light, or red plus far-red, at levels that inhibit flowering when applied during the middle of the inductive dark period, either had no effect on the initiation of dark measurement (i.e., were perceived as darkness), or they delayed the initiation of dark measurement by various times up to the full interval of exposure (2 hours). Far-red light alone had virtually no effect either at the beginning or in the middle of the dark period. These results confirm that time measurement in the photoperiodic response of short-day Xanthium plants is not simply the time required for metabolic dark conversion of phytochrome. Results also suggest that the pigment system (phytochrome?) and/or responses to it may be significantly different as they function during twilight (initiation of dark measurement), and as they function during a light break several hours later. Possible mechanisms by which cocklebur plants detect the change from light to darkness are discussed.COMPARING EXPERIMENTAL RESULTS WITH SPECTRAL LIGHT MEASUREMENTS DURING TWILIGHT AND WITH MEASUREMENTS OF LIGHT FROM THE FULL MOON LED TO TWO CONCLUSIONS: First, light levels pass from values perceived by the plant as full light to values perceived as complete darkness in only about 5.5 to 11.5 minutes, although twilight as perceived by the human eye lasts well over 30 minutes. Second, cocklebur plants probably do not respond to light from the full moon, even when most sensitive, 7 to 9 hours after the beginning of darkness.

Journal Article↗
PubMed1981

Flowering in Xanthium strumarium: INITIATION AND DEVELOPMENT OF FEMALE INFLORESCENCE AND SEX EXPRESSION.

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 timing of action of high temperature were shown to be similar for both the apical male and lateral female inflorescences.Strong photoperiodic induction of the plants favored female sex expression, while maleness was enhanced by exogenous gibberellic acid. The problem of the control of sex expression in Xanthium is discussed in relation to the distribution pattern of male and female inflorescences on the flowering shoot and to the state of the meristem at the time of the arrival of the floral stimulus.

Journal Article↗
PubMed1983

Metabolism of Abscisic Acid and Its Regulation in Xanthium Leaves during and after Water Stress.

Metabolism of abscisic acid was compared in stressed and in rehydrated leaf blades of Xanthium strumarium L. Chicago strain that were either detached or left intact on the plant. Under all conditions, phaseic acid was the major metabolite. The high level of phaseic acid that was observed in intact plants 1 day after recovery from stress declined slowly and had not yet reached the prestress level 1 week later. The glucosyl ester of abscisic acid, beta-d-glucopyranosyl abscisate, accumulated at a low rate during periods of prolonged stress. Repeated stress-recovery cycles resulted in a gradual increase in the level of the glucosyl ester, which did not decline following relief of stress for at least 34 days. The level of the glucosyl ester of abscisic acid may therefore serve as a cumulative indicator of the water stresses to which a particular leaf has been exposed.Darkness stimulated abscisic acid metabolism in both detached and attached leaves. Treatment of Xanthium leaves in light with ethylene or chemicals that release ethylene also resulted in a faster breakdown of abscisic acid. Inasmuch as darkness is known to stimulate ethylene production, it is proposed that enhancement of abscisic acid metabolism in darkness is mediated by ethylene.

Journal Article↗
PubMed1984

Abscisic Acid Metabolism in Relation to Water Stress and Leaf Age in Xanthium strumarium.

Intact plants of Xanthium strumarium L. were subjected to a water stress-recovery cycle. As the stress took effect, leaf growth ceased and stomatal resistance increased. The mature leaves then wilted, followed by the half expanded ones. Water, solute, and pressure potentials fell steadily in all leaves during the rest of the stress period. After 3 days, the young leaves lost turgor and the plants were rewatered. All the leaves rapidly regained turgor and the younger ones recommenced elongation. Stomatal resistance declined, but several days elapsed before pre-stress values were attained.Abscisic acid (ABA) and phaseic acid (PA) levels rose in all the leaves after the mature ones wilted. ABA-glucose ester (ABA-GE) levels increased to a lesser extent, and the young leaves contained little of this conjugate. PA leveled off in the older leaves during the last 24 hours of stress, and ABA levels declined slightly. The young leaves accumulated ABA and PA throughout the stress period and during the 14-hour period immediately following rewatering. The ABA and PA contents, expressed per unit dry weight, were highest in the young leaves. Upon rewatering, large quantities of PA appeared in the mature leaves as ABA levels fell to the pre-stress level within 14 hours. In the half expanded and young leaves, it took several days to reach pre-stress ABA values. ABA-GE synthesis ceased in the mature leaves, once the stress was relieved, but continued in the half expanded and young leaves for 2 days.Mature leaves, when detached and stressed, accumulated an amount of ABA similar to that in leaves on the intact plant. In contrast, detached and stressed young leaves produced little ABA. Detached mature leaves, and to a lesser extent the half expanded ones, rapidly catabolized ABA to PA and ABA-GE, but the young leaves did not. Studies with radioactive (+/-)-ABA indicated that in young leaves the conversion of ABA to PA took place at a much lower rate than in mature ones. Leaves of all ages rapidly conjugated PA to PA-glucose ester. Furthermore, when half expanded leaves were stressed on the intact plant, their rate of ABA catabolism was enhanced, an effect not observed in the young leaves.In conclusion, young leaves on intact Xanthium plants produce little stress-induced ABA themselves, but due to import and a low rate of catabolism accumulate more ABA and PA than mature leaves.

Journal Article↗
PubMed1986

Compartmentation and equilibration of abscisic Acid in isolated xanthium cells.

The compartmentation of endogenous abscisic acid (ABA), applied (+/-)-[(3)H]ABA, and (+/-)-trans-ABA was measured in isolated mesophyll cells of the Chicago strain of Xanthium strumarium L. The release of ABA to the medium in the presence or absence of DMSO was used to determine the equilibration of ABA in the cells. It was found that a greater percentage of the (+/-)-[(3)H]ABA and the (+/-)-trans-ABA was released into the medium than of the endogenous ABA, indicating that applied ABA did not equilibrate with the endogenous material.Therefore, in further investigations only the compartmentation of endogenous ABA was studied. Endogenous ABA was released from Xanthium cells according to the pH gradients among the various cellular compartments. Thus, darkness, high external pH, KNO(2), and droughtstress all increased the efflux of ABA from the cells. Efflux of ABA from the cells in the presence of 0.6 m mannitol occurred within 30 seconds, but only 8% of the endogenous material was released during the 20 minute treatment.

Journal Article↗
PubMed1965

Comparison of messenger RNA in photoperiodically induced and noninduced Xanthium buds.

In response to the floral stimulus, Xanthium buds synthesize relatively more messenger RNA than do vegetative buds. This is demonstrated by fractionation, on methylated albumin-kieselguhr columns, of a mixture of nucleic acids from vegetative and induced buds, one being labeled with uridine-H(3) and the other with uridine-2-C(14). While floral induction stimulates a small increase in messenger RNA synthesis as revealed by labeling intact plants, this difference can be magnified by labeling excised buds in solution. From experiments with excised buds from Xanthium plants, it is concluded that buds from photoperiodically induced plants contain more messenger RNA than buds from noninduced ones do.

Carbon Isotopes↗
PubMed1990

Cocklebur toxicosis in cattle associated with the consumption of mature Xanthium strumarium.

Cockleburs (Xanthium spp.) are herbaceous annuals with worldwide distribution. Toxicoses are usually associated with the consumption of the seedlings in the cotyledon stage, which contain a high concentration of the toxic principle, carboxyatractyloside. The seeds are also known to contain the toxin, but it has long been assumed that the spiny capsule would deter their consumption. Six of 70 yearling calves died while being fed round bale hay composed predominantly of foxtail and mature cocklebur plants with burs. Clinical signs ranged from acute death to hyperexcitability, blindness, tense musculature, and spastic gaits with heads held high and ears erect. Some symptomatic calves would stumble, fall to lateral recumbency, convulse, and later recover. Overall, the herd was very uneasy. Prominent gross lesions were ascites and a firm, pale liver with a mottled hemorrhagic pattern on cut surface. The rumen contained numerous intact burs and well-ruminated grass. Histological examination of the liver revealed marked centrolobular degeneration and necrosis with associated hemorrhage and congestion. Brain lesions were present. Plant and tissue samples were analyzed for carboxyatractyloside with various results. Samples of rumen contents, urine, and burs contained 100-200 ppm, 0.1-0.05 ppm, and 0.1 ppm, respectively. Based on the history, clinical signs, pathological lesions, and chemical analyses, cocklebur toxicosis associated with consumption of mature Xanthium strumarium in hay was confirmed.

Animal Feed↗
PubMed2026

Integrated phytochemical and bioactivity profiling of Xanthium strumarium fruits from Korea and China: Implications for origin-specific quality specification.

BACKGROUND: Geographic origin influences the phytochemical composition and biological activities of medicinal plant resources. Xanthium strumarium L. (XS) fruit is widely used in East Asian traditional medicine. However, current pharmacopeial standards primarily recognize Chinese-derived material, despite the availability and traditional use of XS in Korea. To address this gap and support origin-informed quality specification, we compared fruits from Korea (XS-K) and China (XS-C) using chloroplast genome sequencing, targeted phytochemical profiling (high-performance liquid chromatography (HPLC) for selected phenolics and gas chromatography-flame ionization detection (GC-FID) for fatty acids and phytosterols, and multivariate chemometric analysis. RESULTS: Chloroplast genome analysis revealed high overall similarity but localized divergence around the rpoC2 locus and a greater mutation burden in XS-C, supporting origin-associated genomic differentiation. Phytochemical profiling revealed distinct origin-dependent metabolic signatures. XS-K showed higher levels of phytosterols, chlorogenic acid, 4,5-dicaffeoylquinic acid (4,5-DCQ), and xanthatin was detected only in XS-K, whereas XS-C exhibited greater abundance of total fatty acids, particularly oleic acid. Unsupervised clustering and log2 fold-change ranking confirmed clear compositional separation, and variable importance in projection (VIP) analysis identified chlorogenic acid, β-sitosterol, oleic acid, 4,5-DCQ, and xanthatin as major discriminators between origins. Bioactivity assays demonstrated that XS-K exerted stronger antioxidant effects in ABTS, DPPH and FRAP assays, stronger skin-related enzyme inhibition, and greater antibacterial activity against Staphylococcus aureus, consistent with its enriched phenolic and sterol profile. CONCLUSION: Together, chloroplast sequence variation, targeted metabolite quantification, and screening bioassays consistently distinguished XS-K from XS-C. These findings support the use of candidate markers for the origin-based authentication and quality control of XS fruit-derived ingredients. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fruit↗
PubMed2003

Reproductive allocation of an annual, Xanthium canadense, at an elevated carbon dioxide concentration.

Stimulation of vegetative growth by an elevated CO(2) concentration does not always lead to an increase in reproductive yield. This is because reproductive yield is determined by the fraction of biomass allocated to the reproductive part as well as biomass production. We grew Xanthium canadense at low N (LN) and high N levels (HN) under an ambient (360 micromol mol(-1)) and elevated (700 micromol mol(-1)) CO(2) concentration ([CO(2)]) in open-top chambers. Reproductive yield was analysed as the product of: (1) the duration of the reproductive period, (2) the rate of dry mass acquisition in the reproductive period, and (3) the fraction of acquired biomass allocated to the reproductive part. Elevated [CO(2)] increased the total amount of biomass that was allocated to reproductive structures, but this increase was caused by increased capsule mass without a significant increase in seed production. The increase in total reproductive mass was due mainly to an increase in the rate of dry mass acquisition in the reproductive period with a delay in leaf senescence. This positive effect was partly offset by a reduction in biomass allocation to the reproductive part at elevated [CO(2)] and HN. The duration of the reproductive period was not affected by elevated [CO(2)] but increased by HN. Seed production was strongly constrained by the availability of N for seed growth. The seed [N] was very high in X. canadense and did not decrease significantly at elevated [CO(2)]. HN increased seed [N] without a significant increase in seed biomass production. Limited seed growth caused a reduction in biomass allocation to the reproductive part even though dry mass production was increased due to increased [CO(2)] and N availability.

Carbon Dioxide↗
PubMed2005

Dynamics of leaf area and nitrogen in the canopy of an annual herb, Xanthium canadense.

We studied leaf area and nitrogen dynamics in the canopy of stands of an annual herb Xanthium canadense, grown at a high (HN)- and a low-nitorgen (LN) availability. Standing leaf area increased continuously through the vegetative growth period in the LN stand, or leveled off in the later stage in the HN stand. When scaled against standing leaf area, both production and loss rates of leaf area increased but with different patterns: the production rate was retarded, while the loss rate was accelerated, implying an upper limit of standing leaf area of the canopy. The rate of leaf-area production was higher in the HN than in the LN stand, which was caused by the higher rate of leaf production per standing leaf area as well as the greater standing leaf area in the HN stand. Although the rate of leaf-area loss was higher in the HN than in the LN stand, it was not significantly different between the two stands when compared at a common standing leaf area, suggesting involvement of light climate in determination of the leaf-loss rate. On the other hand, the rate of leaf-area loss was positively correlated with nitrogen demand for leaf area development across the two stands, suggesting that leaf loss was caused by retranslocation of nitrogen for construction of new leaves. A simple simulation model of leaf and nitrogen dynamics in the canopy showed that, at steady state, where the rate of leaf-area loss becomes equal to the production rate, the standing leaf area was still greater in the HN than in the LN stand. Similarly, when the uptake and loss of nitrogen are equilibrated, the standing nitrogen was greater in the HN than in the LN stand. These results suggest that leaf-area production is strongly controlled by nitrogen availability, while both nitrogen and light climate determine leaf-loss rates in the canopy.

Analysis of Variance↗
PubMed2005

Antileishmanial and antifungal activities of xanthanolides isolated from Xanthium macrocarpum.

Seven xanthanolides, xanthinosin, xanthatin, 4-hydroxyxanthinosin, xanthinin, 4-epiisoxanthanol, 4-epixanthanol, 2-hydroxyxanthinosin and 4-oxobedfordia acid, were isolated from the fruits of Xanthium macrocarpum. A valuation of the antifungal activity of these xanthanolides against Candida albicans, Candida glabrata and Aspergillus fumigatus and of their antileishmanial activity against Leishmania infantum and Leishmania mexicana is presented.

Animals↗
PubMed2003

Two cytotoxic sesquiterpene lactones from the leaves of Xanthium strumarium and their in vitro inhibitory activity on farnesyltransferase.

Two xanthanolide sesquiterpene lactones, 8- epi-xanthatin (1) and 8- epi-xanthatin epoxide (2), isolated from the leaves of Xanthium strumarium (Compositae), demonstrated a significant inhibition on the proliferation of cultured human tumor cells, i. e., A549 (non-small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nervous system) and HCT-15 (colon) in vitro. They were also found to inhibit the farnesylation process of human lamin-B by farnesyltransferase (FTase), in a dose-dependent manner in vitro (IC 50 value was calculated as 64 and 58 microM, respectively). Due to the relatively high concentrations of 1 and 2 required to obtain an FTase inhibition as compared with those necessary for a cytotoxic effect on tumor cells, it remains unclear whether a relationship between these two activities exists.

Alkyl and Aryl Transferases↗
PubMed2005

A new heterocyclic glucoside from the fruits of Xanthium pungens.

A new thiazinedione glucoside, 7-(beta-D-glucopyranosyloxymethyl)-8,8-dimethyl-4,8-dihydrobenzo[1,4]thiazine-3,5-dione (1) and named xanthiside, was isolated from the methanol extract of the fruits of Xanthium pungens. Its structure was determined by spectroscopic techniques including, IR, CIMS, high-resolution-EIMS, and extensive 400 MHz one- and two-dimensional NMR-analysis (1H, 13C-NMR, DEPT, 1H-1H COSY, HMQC, COLOC, and NOE experiments).

Chemistry Techniques, Analytical↗