Artichoke Thistle Research Articles

Determination of optimal doses of glyphosate for controlling weeds at several stages in southwestern Buenos Aires province (Argentina)

AbstractEfficient weed management is essential for avoiding competition for water, light, and nutrient resources in semiarid zones. Chemical weed control with glyphosate was evaluated on perennial wall-rocket (Diplotaxis tenuifolia), artichoke thistle (Cynara cardunculus), slender wild oat (Avena barbata), and perennial ryegrass (Lolium perenne). Plants at early, middle and advanced vegetative stages were used in this study. Glyphosate potassium salt was applied at rates of 0.0675 (1/16x), 0.135 (1/8x), 0.27 (1/4x), 0.54 (1/2x), 1.08 (x) and 2.16 (2x) kg acid equivalent (ae) · ha−1. Glyphosate combined with 2,4-D amine salt was evaluated at rates of 1.08 kg ae · ha−1and 0.53 kg active ingredient (ai) · ha−1, respectively. The volume of the spray was 100 l · ha−1with 86 droplets · cm−2and a Volume Median Diameter (VMD) of 421.19 μm. In general, all the tested weeds were controlled with a quarter of the label rate. Three sizes of tested plants were controlled in a similar way at the same glyphosate dose rate. Moreover, the addition of 2,4-D to glyphosate did not produce an increase in the control of broadleaf weeds. The results showed that glyphosate was effective in controlling the tested weed species, including low application rates for all the growth stages in the southwestern Buenos Aires province.

Redescription of Lasioseius cynari Chant, 1963 (Acari: Mesostigmata: Blattisociidae)

A redescription of adults of Lasioseius cynari Chant, 1963 is presented based on the examination of paratype specimens deposited at the Canadian National Collection of Insects and Arachnids, Canada and on specimens from Argentina. The paratype specimens originated from Italy were collected from globe artichokes (Cynara scolymus L.) and the specimens from Argentina were collected from the same host and from artichoke thistle (Cynara cardunculus L.), both Asteraceae. This is the first report of this species after its original description, and a new host record of this species on C. cardunculus.

Comparative structure-function characterization of the saposin-like domains from potato, barley, cardoon and Arabidopsis aspartic proteases

The present study characterized the aspartic protease saposin-like domains of four plant species, Solanum tuberosum (potato), Hordeum vulgare L. (barley), Cynara cardunculus L. (cardoon; artichoke thistle) and Arabidopsis thaliana, in terms of bilayer disruption and fusion, and structure pH-dependence. Comparison of the recombinant saposin-like domains revealed that each induced leakage of bilayer vesicles composed of a simple phospholipid mixture with relative rates Arabidopsis>barley>cardoon>potato. When compared for leakage of bilayer composed of a vacuole-like phospholipid mixture, leakage was approximately five times higher for potato saposin-like domain compared to the others. In terms of fusogenic activity, distinctions between particle size profiles were noted among the four proteins, particularly for potato saposin-like domain. Bilayer fusion assays in reducing conditions resulted in altered fusion profiles except in the case of cardoon saposin-like domain which was virtually unchanged. Secondary structure profiles were similar across all four proteins under different pH conditions, although cardoon saposin-like domain appeared to have higher overall helix structure. Furthermore, increases in Trp emission upon protein-bilayer interactions suggested that protein structure rearrangements equilibrated with half-times ranging from 52 to 120s, with cardoon saposin-like domain significantly slower than the other three species. Overall, the present findings serve as a foundation for future studies seeking to delineate protein structural features and motifs in protein-bilayer interactions based upon variability in plant aspartic protease saposin-like domain structures.

Biological Effect of Cynara cardunculus on Kidney Status of Hypercholesterolemic Rats.

Context:Cynara cardunculus or artichoke thistle belongs to the sunflower family and has a variety of cultivable forms. Historically, it was cultivated as a vegetable, but more recently, it is being used in cheese and biofuel preparation. Artichoke leaf extracts are also known for its medicinal purposes, particularly in reducing the elevated cholesterol levels in blood. Hypercholesterolemia (HC) is also associated with other complications such as impaired renal function and diabetes mellitus. A remedy without major side effects for HC and its associated complications is highly desirable.Aims:We explored the effect of artichoke on the kidneys of hypercholesterolemic adult male Sprague–Dawley albino rats.Subjects and Methods:Oral administration of 200 mg/kg and 400 mg/kg body weight (b.wt.) of C. cardunculus leaf extract (CCL) and C. cardunculus pulp extract (CCP) was made to male Sprague–Dawley albino hypercholesterolemic rats and investigated the levels of glucose, creatinine, uric acid, and urea in their blood.Results:We observed that both CCL and CCP significantly reduced the creatinine and uric acid levels in the blood in a dose-dependent manner (P < 0.05). Both CCL and CCP significantly reduced the blood glucose levels (P < 0.05). Further, the histopathological investigation of the kidney sections showed that CCL treatment resolved HC-associated kidney damage.Conclusion:CCL not only has cholesterol-reducing capacity but also reduces the blood glucose levels and repairs the impaired kidney functions and damages. These findings are significant particularly because HC results in further complications such as diabetes and kidney damage, both of which can be treated effectively with artichoke.SUMMARY C. cardunculus leaf extract (CCL) not only has cholesterol-reducing capacity but also reduces the blood glucose levels and repairs the impaired kidney functions and damages. This study evaluated the nephroprotective role of CCL and CCP in hypercholesterolemic rats and observed that both CCL and CCP significantly reduced the creatinine and uric acid levels in hypercholesterolemic rats in a dose-dependent manner. Abbreviations used: HC: Hypercholesterolemia, WHO: World Health Organization, BAS: Bile acid sequestrant, PCSK9: Proprotein convertase subtilisin kexin type 9, ALE: Artichoke leaf extract, CCL: Cynara cardunculus leaf extract, CCP: Cynara cardunculus pulp extract, BWG%: Body weight gain%, FER: Food-efficiency ratio.

California—Where Two Worlds Collided: The Arising Researcher

I remember how much it stung. I was still peddling but slowed to an abrupt stop after I looked down and saw the sienna-colored ooze emanating from my knee, dripping down to my ankle. I had been riding on my mountain bike through one of the world's greatest single-track amidst the muted, earth tone ruffles of coastal sage scrub plants that nestled in the foothills of the Santa Ana Mountains of southern California. The scrubland that transitioned into chaparral when I climbed and stood out of the saddle; the reprieve of shade from the oaks when a long descent made me drop, aerodynamically, behind the seat; and the preserves, state parks, and Cleveland National Forest whose trails and colors I had memorized by heart—these were the wild places that comprised the laboratory of my childhood. That I needed to give ample space between my peddling legs and the saw-toothed, spiny leaved artichoke thistle was just not in my muscle memory. I plucked out unidentifiable plant organ parts, one-by-one, painfully from my knee. But this was not the only intrusion. There were hillslopes with cover crops of the exotic mustards, horehound along trail edges, and tobacco weed along the streams. But the exotic grasses—the wild oats and bromes—these were different strangers. The grasses were everywhere. Recreating in the remnant patches of shrublands that had been pardoned from suburban development, I knew from a young age that I lived somewhere special: a biodiversity hotspot. Despite the known threat of exotic invasive grasses I learned by name, I had solace in that it appeared a laborious, but manageable, gardening effort. And, I grew exceedingly more fascinated with true nature—the natural processes within these semiarid ecosystems not modulated by humans. As an undergraduate, I came across Carla M. D'Antionio and Peter Vitousek's review, “Biological Invasions by Exotic Grasses, the Grass/Fire Cycle, and Global Change.” I read how this conversion was not just happening in my ochre and celadon foothills—this was systemic. It was the first time I read the term “global change” and the radicle of a burden to do something emerged, competing for space with my desires to study a more pure ecology after the early works of Ehleringer and Mooney. Carla and Peter's paper would set the framework for my master's research that revealed disturbances of biological soil crust in coastal sage scrub increases emergence of exotic vascular plants, particularly annual grasses from the Mediterranean Basin. Their review connected my work to the next dot, “Grasses have long been recognized as good competitors against herbaceous and woody species.” And, like an omen, the paper came to mind when my entire field experiment burned in the Santiago Fire of 2007. Their paper would also weave into my decision to be among the ten individuals comprising the first cohort of Earth System Science Ph.D.'s at Stanford University. There, I gained more confidence in my ability to contribute to a global synthesis of ecological knowledge. I also grew more comfortable as a 21st century ecologist: studying an ecology in aridlands familiar to those who came before but also engaged in solving applied problems addressing nexus-type issues with data-intensive experiments related to energy generation, land, and global change. I have begun to understand that it is difficult, if not impossible, for 21st century ecologists to emulate identical paper trails left by the great naturalists that came before us; not because there is nothing left to discover, instead it is because now there is too much to save. As a new Assistant Professor at UC Davis, I reread Carla's paper again with equal parts awe and nostalgia, knowing those who traverse down my paper trail will experience a different journey, but hoping it equally influential for the century I live in.

Novel Use of Trinexapac-Ethyl to Study Weed Seed Germination

Understanding seed biology and onset of germination requirements is a key point for designing effective weed management programs. Gibberellins (GAs) are known to play a role in onset of germination of several species. Onset of germination often requires an increase in de novo GA content or an increase in sensitivity to GAs. Reduced germination of seeds incubated in solutions containing compounds that inhibit GA synthesis provide evidence that GAs are required to trigger germination. Trinexapac-ethyl (TE), a GA synthesis inhibitor, is frequently used as a plant growth regulator in crop production. However, to the best of our knowledge, TE has not been used to study the requirement of GAs in onset of germination. Germination studies were conducted using seeds of artichoke thistle and common teasel under a range of TE concentrations (0 to 500 μM TE), a combined solution of 125 μM TE + 100 μM GA3for artichoke, and 250 μM TE + 100 μM GA3for common teasel. Germination tests were conducted at 20/10 C (12-h thermoperiod) in darkness for artichoke and at constant 15 C with 12 h of light for common teasel. Germination of artichoke in 125 μM TE was reduced to 47% when compared with the check (95%), but the combined TE + GA3solution maintained germination at 84%. Germination of common teasel in 250 μM TE was reduced to 10% when compared with the check (91%), and the combined TE + GA3solution increased germination to 63%. These results demonstrate the utility of TE to study the role of GAs in onset of germination. This novel use of TE is a valuable option to study germination requirements of weed species, and therefore contributes to the design of weed management programs.

More than multiple introductions: Multiple taxa contribute to the genesis of the invasive California's wild artichoke thistle

AbstractThe history of some invasive species is so complex that their origins can be difficult to determine. One example of such invasive species is the California invasive known as “wild artichoke thistle” (Cynara cardunculus var. sylvestris), found in natural and disturbed ecosystems. Wild artichoke thistle is a Mediterranean native and the progenitor of two domesticated horticultural taxa, artichoke and cardoon. Different hypotheses regarding the origins of California plants have included introductions by 19th century Italian immigrants and the de‐domestication (evolutionary reversion to wild‐type morphology) of feral (escaped, free‐living) cultivars. Using microsatellite markers, we compared the genetic constitutions of 12 artichoke thistle populations in California with possible progenitor populations: 17 Spanish and Italian wild populations and eight different artichoke and cardoon cultivars. Each California population was compared with its putative progenitors using STRUCTURE analysis. Our results suggest that California's artichoke thistle populations are polyphyletic. Surprisingly, two‐thirds of California's populations closely matched populations from the Iberian Peninsula. Three populations matched domesticated artichoke. One population appears to have wild and cultivar hybrid ancestry. Alleles specific to Italian populations were found at low frequencies in some California plants, suggesting that Italian wild plants may have been in California, but have left a trivial genetic legacy. Given that the de‐domesticated plants in this study appear to be as invasive as the wild taxon, we conclude with a discussion of the role that ferality and de‐domestication may have in plant invasions.

Balancing Active and Passive Restoration in a Nonchemical, Research-Based Approach to Coastal Sage Scrub Restoration in Southern California

Coastal sage scrub restoration at Audubon’s Starr Ranch Sanctuary commences with nonchemical control of a high-priority non-native in degraded (and native) grasslands, artichoke thistle (<i>Cynara cardunculus</i>). Scrub restoration begins the second year of artichoke thistle control. Here I report on how our approach combines active and passive restoration. We use experiments, when time and funding allow, to help guide the active restoration process by answering questions on technique: the effectiveness of soil tamping, differing seed rates, and timing of planting on restoration success. As a result of past experiments, our field crews tamp seeds into soil after hand broadcasting both early (October) and late ( January) each season. Passive processes are compatible with coastal sage scrub restoration since shrub dominants are proficient natural grassland colonizers. We monitor both active and passive restoration sites quantitatively and qualitatively and have demonstrated success that is highly dependent on levels of annual precipitation. We at Starr Ranch believe that our nonchemical, research-based project can serve as a model of a rigorous, sustainable approach to land management in southern California.

The impact of invasion and subsequent removal of an exotic thistle, Cynara cardunculus, on CO2 and H2O vapor exchange in a coastal California grassland

Changes in vegetation structure and composition, particularly due to the invasion of exotic species, are predicted to influence biosphere-atmosphere exchanges of mass and energy. Invasion of Cynara cardunculus (cardoon or artichoke thistle), a perennial, non-native thistle in coastal California grasslands presently dominated by non-native annual grasses, may alter rates of ecosystem CO2 exchange and evapotranspiration (ET). During spring and summer 2006, we compared midday maximum net ecosystem CO2 exchange (NEE) and ET among adjacent grassland plots where Cynara was present and where it was absent. Measurements of NEE supported the prediction that deeply-rooted Cynara increase midday ecosystem C-assimilation. Cynara-mediated shifts in NEE were associated with increases in ecosystem photosynthesis rather than changes in ecosystem respiration. Furthermore, the presence of Cynara was associated with increased ET during the growing season. An increase in aboveground live biomass (a proxy for leaf area) associated with Cynara invasion may underlie shifts in ecosystem CO2 and water vapor exchange. Following mid-growing season sampling during April, we removed Cynara from half of the Cynara-containing plots with spot applications of herbicide. Three weeks later, midday fluxes in removal plots were indistinguishable from those in plots where Cynara was never present suggesting a lack of biogeochemical legacy effects. Similar to woody-encroachment in some semi-arid ecosystems, Cynara invasion increases midday ecosystem CO2 assimilation and evapotranspiration rates and has the potential to increase C-storage in California coastal grasslands.

Thermogravimetry/mass spectrometry study of woody residues and an herbaceous biomass crop using PCA techniques

The devolatilization behaviour of pine and beech wood from carpentry residuals and an herbaceous product from an energy plantation (artichoke thistle) was investigated by thermogravimetry/mass spectrometry (TG/MS). The effect of three pre-treatments, hot-water washing, ethanol extraction and their combination, was also studied. Principal component analysis (PCA) was employed to help in the evaluation of the large data set of results. The characteristics of the thermal decomposition of the herbaceous crop are considerably different from that of the woody biomass samples. The evolution profiles of some characteristic pyrolysis products revealed that the thermal behaviour of wood and thistle is still considerably different after the elimination of some of the inorganic ions and extractive compounds, although the macromolecular components of the samples decompose at similar temperatures. With the help of the PCA calculations, the effect of the different pre-treatments on the production of the main pyrolysis products was evidenced.

Competition of artichoke thistle (Cynara cardunculus) with native and exotic grassland species

Determining the nature of root and shoot competition can elucidate the competitive ability of an invasive species and direct management strategies. In a set of competition experiments, artichoke thistle (Cynara cardunculus), an exotic invasive perennial forb, was subjected to full or shoot competition with four species: black mustard (Brassica nigra), an exotic annual forb; ripgut grass (Bromus diandrus), an exotic annual grass; purple needle-grass (Nassella pulchra), a native perennial grass; and itself. For shoot competition, a smaller pot nested in a larger experimental pot sequestered the target plant root system. A bare ground invasion experiment, in which all plants were transplanted on the same date, and a community invasion experiment, in which competitor species were planted 1 mo before targets, were conducted. In the bare ground invasion experiment, target plant size was reduced (P ≤ 0.05) when exposed to full competition with the exotic species, but not purple needle-grass. Effects on target plants included reductions in height, number of leaves, rosette diameter, and shoot and leaf dry weight. In the community invasion experiment, full competition with all species reduced target plant growth (P ≤ 0.05). Shoot competition was more important when all species were planted synchronously, whereas root competition was more important when target plant establishment was delayed. In a separate experiment, artichoke thistle was grown under four light levels simulating field conditions under canopies of the same competitors. Midday carbon assimilation decreased linearly with increased shade, indicating the likely effects of shoot competition on artichoke thistle. Results indicated that exotic species are more competitive than native purple needle-grass against artichoke thistle and that restoration directly to native grassland after artichoke thistle removal might be difficult. However, artichoke thistle seedling growth is reduced by root competition from grasses that emerge earlier, indicating that early season management of grasslands to delay artichoke thistle establishment might provide effective control.

Slow Pyrolysis of Woody Residues and an Herbaceous Biomass Crop: A Kinetic Study

The devolatilization behavior of pine and beech wood from carpentry residues and an herbaceous product from an energy plantation (artichoke thistle) was investigated by thermogravimetry. The effect of three pretreatments, hot-water washing, ethanol extraction, and a combination, were also studied. Various approaches based on first and nth order partial reactions in a summative model of pseudocomponents were employed to determine the best kinetic parameters that describe the experiments both at linear and stepwise heating programs. The assumption of four partial reactions appropriately described the global decomposition of most of the samples, while a low-temperature partial reaction was needed for the untreated pine. After the separate kinetic parameters for each of the samples were determined, a further check on the effects of the pretreatments was carried out by determining how a common set of activation energies describes the untreated and pretreated samples of the same feedstock.