Thistle Species Research Articles

Climate warming increases insect-driven seed removal of two elaiosome-bearing invasive thistle species.

Ants and other insects are often a source of localized secondary dispersal for wind-dispersed plants and thus play an important ecological role in their spatial dynamics, but there is limited information on how climate change will affect such dispersal processes. Here, we use field experiments to investigate how climate warming affects seed removal, as this initiation of movement represents the first step in insect-driven secondary dispersal. Our results indicate that for the invasive thistles Carduus nutans and Carduus acanthoides, increased growing temperature influences seed attractiveness to insect dispersers, with seeds from maternal plants grown at temperatures 0.6°C above ambient removed by insect dispersers at higher rates than their unwarmed counterparts. We also observe that seed elaiosomes in these two species play an important role in dispersal, as seeds without elaiosomes were significantly less likely to be removed over the same period. Significant interactions between elaiosome presence/absence and warming treatment were also observed, though only for C. acanthoides, with the boost in seed removal from warming dampened when the elaiosome was present compared to when it was absent. These findings provide evidence that climate warming may alter aspects of dispersal such as seed removal by secondary dispersers, with potential ramifications for dispersal in future climates since seed-bearing plants around the world may be subject to increased growing temperatures, and many of these plant species bear elaiosomes and experience seed dispersal by insects.

Elevated temperatures shift flower head height distributions and seed dispersal patterns in two invasive thistle species.

Climate change may significantly alter how organisms disperse, with implications for population spread and species management. Wind-dispersed plants have emerged as a useful study system for investigating how climate change affects dispersal, although studies modeling wind dispersal often assume propagules are released from a single point on an individual. This simplifying assumption, while useful, may misestimate dispersal. Here, we investigate the effects of climate change on dispersal distances and spread rates, examining how these quantities shift when accounting for all points of seed release on an individual. Using the wind-dispersed invasive thistles Carduus nutans and Carduus acanthoides, we quantify temperature-driven shifts in the distribution of flower head heights using a passive warming field experiment, and estimate how these shifts affect dispersal using the Wald analytical long-distance (WALD) model; for C. nutans, we use existing demographic data to simulate how these shifts affect population spread rates. We also compare dispersal distances for both warmed and ambient temperature plants, considering the entire distribution of flower head heights versus the common assumption of point-source seed release at the maximum height. For experimentally grown individuals, an ~0.6°C higher growing temperature increased mean and maximum flower head height by 14.1 cm (15.0%) and 14.0 cm (13.2%), respectively, in C. nutans and by 21.2 cm (26.6%) and 31.8 cm (36.7%), respectively, in C. acanthoides. Seeds from warmed individuals were more likely to exceed a given dispersal distance than those from their unwarmed counterparts; warmed C. nutans and C. acanthoides seeds were on average 1.36 and 1.71 times as likely, respectively, to travel 10 m or more in dispersal simulations, with this disparity increasing at longer dispersal distances. For C. nutans, increased growing temperatures boosted simulated rates of population spread by 42.2%, while assuming dispersal from a maximum height point source rather than the true distribution of flower head heights increased simulated spread by up to 28.5%. Our results not only demonstrate faster population spread under increased temperatures, but also have substantial implications for modeling such spread, as the common simplifying assumption of dispersal from a single maximum height source may substantially overestimate spread rates.

Silymarin ameliorates peritoneal fibrosis by inhibiting the TGF-β/Smad signaling pathway.

Peritoneal dialysis (PD) is the mainstay of treatment for renal failure replacement therapy. Although PD has greatly improved the quality of life of end-stage renal disease (ESRD) patients, long-term PD can lead to ultrafiltration failure, which in turn causes peritoneal fibrosis (PF). Silymarin (SM) is a polyphenolic flavonoid isolated from the milk thistle (Silybum marianum) species that has a variety of pharmacological actions, including antioxidant, anti-inflammatory, antiviral, and anti-fibrotic pharmacological activities. However, the effect of SM on PF and its potential mechanisms have not been clarified. The aim of this study was to investigate the preventive effect of SM on PF in vitro and in vivo as well as elucidate the underlying mechanisms. We established PF mouse models and human pleural mesothelial cell fibrosis in vitro by intraperitoneal injection of high-glucose peritoneal dialysis solution (PDS) or transforming growth factor-β1 (TGF-β1), and evaluated the effect of SM on peritoneal fibrosis in vivo and in vitro. We found that SM alleviated peritoneal dysfunction. Meanwhile, SM inhibited the expression of fibrotic markers (TGF-β1, collagen I, fibronectin) and restored the expression of E-cadherin, BMP-7 in PF mice and TGF-β1-treated Met-5A cells. Furthermore, SM markedly down-regulated the expression of TGF-β1, p-Smad2, and p-Smad3 and up-regulated the expression of smad7. In conclusion, these findings suggested that SM may be an efficient and novel therapy for the prevention of PF through inhibition of TGF-β/Smad signaling.

Thistles: consumer properties and their use for food purposes

The article discusses the use of weed species of thistles. Their nutritional value, active substances, and recipes for dishes from thistles are given. That allows us considering these plants from the perspective of a functional additive in culinary recipes.

Long‐term proliferation of large annual thistles in dry Mediterranean rangelands

AbstractSpiny plants comprise a large, ecologically and economically important functional group in Mediterranean rangelands. The increasing abundance of large annual thistles in grazed grasslands entails major consequences for ecosystem services. This study aims to quantify the contribution of large annual spiny plants to rangeland vegetation cover and productivity and to identify management‐ and climate‐related drivers of spiny plant distribution and performance. Using a 15‐year dataset from an extensive herbaceous pasture experiment in northeastern Galilee, Israel, we examined the effects of livestock management and climate on the cover and biomass of two dominant annual thistle species, Scolymus maculatus and Carthamus glaucus. These thistles constitute a significant proportion of pasture productivity, contributing more than 50% and 25% under high and moderate stocking density, respectively. Despite the similarity in life‐form and life‐history characteristics, each demonstrates a distinct response to both management intensity and annual climatic parameters. High stocking density had a positive effect on both cover and biomass of S. maculatus. Conversely, C. glaucus biomass estimates were higher under moderate stocking density. Distance from feeding site had significant contrasting effects on each of the focal thistles. Relative humidity and temperature were the most sensitive climatic parameters in explaining the variation in cover and biomass of the two thistles. The directionality of the two species' responses suggests that S. maculatus attains higher biomass than C. glaucus under dry and warm conditions. The proliferation of both large thistles under variable stocking densities and climatic conditions increases productivity but reduces the palatable vegetation of Mediterranean rangelands by 27%–50%.

Hiding in plain sight: Two new species of alpine thistles, Cirsium culebraensis and C. funkiae (Cardueae) from the southern Rocky Mountains (United States)

Hiding in plain sight: Two new species of alpine thistles, Cirsium culebraensis and C. funkiae (Cardueae) from the southern Rocky Mountains (United States)

Host recognition by Rhinocyllus conicus of floral scents from invasive and threatened thistles

One of the main obstacles of classical biological control is that biological control organisms cannot be recalled once they are released in nature. It is particularly true for the flowerhead weevil, Rhinocyllus conicus Frolich, which was released as a biological control organism for the invasive musk thistle, Carduus nutans L. (MT). While weevils successfully suppressed introduced populations of musk thistles and other invasive thistle species, non-target attacks have been reported on multiple native thistles including federally listed threatened and endangered (T&E) thistle species. To investigate the foraging behavior of female weevils on invasive and native thistles, we examined volatile organic compounds (VOCs) emitted from MT and a T&E plant species, Sacramento Mountains thistle, Cirsium vinaceum Wooton & Standley (SMT) in the Lincoln National Forest, New Mexico. We used a dynamic headspace volatile collection system and gas chromatography-mass spectrometry to compare volatile profiles between MT and SMT. Female weevils reacted to 7 electrophysiologically active chemical compounds in the blends based on gas chromatography-electroantennography. The behavioral response of female weevils was indifferent when VOCs from both thistles were offered in y-tube olfactometry experiments. Yet, they preferred VOCs collected from MT to purified air. The searching time of female weevils was longer to VOCs collected from SMT over controls. Investigating signals during the initial host recognition of released biological control organisms may open new opportunities to reduce non-target attacks on T&E plant species.

Effect of Planting Density in Two Thistle Species Used for Vegetable Rennet Production in Marginal Mediterranean Areas

In Mediterranean cropping systems, it is important to utilize marginal lands for the cultivation of non-food crops. Spontaneous thistle genera such as Cynara cardunculus L. and Onopordum tauricum Willd. are native to southern Europe. Previous research has focused on their spontaneous growth in the environment or ability to supply biofuel. The aim of this study was to identify the effect of two different planting densities on the flower differentiation, vegetable rennet production and weed control of O. tauricum Willd. and C. cardunculus L. in rainfed unfertilized Mediterranean cropping systems. The results showed that plant density influenced most of the biomass parameters for O. tauricum Willd. but no significant differences were observed for C. cardunculus L. Higher densities of both species were beneficial for weed control. We recommend the use of C. cardunculus L. and O. tauricum Willd. as suitable species for vegetable rennet production in Mediterranean organic cropping systems.

Spill-over attack by the gall fly, Urophora stylata, on congeners of its target weed, Cirsium vulgare

The gall fly, Urophora stylata, was released in New Zealand in 1998 as a biocontrol agent for the thistle weed, Cirsium vulgare (Scotch thistle). In the summer of 2018, a survey was conducted to assess the field host range of the biocontrol agent in New Zealand. A random selection of 18 pasture populations under sheep and/or beef production, where C. vulgare was present, was surveyed to quantify the attack intensity (gall size relative to seedhead size) on C. vulgare, and the presence of attack on other thistle weeds within the same population. At each location, seedheads were collected from C. vulgare and all other thistle species (Cardueae) present, which included Cirsium arvense (Californian thistle), Cirsium palustre (marsh thistle), Carduus nutans (nodding thistle), and an Arctium species (burdock). In addition to attack on C. vulgare, the gall fly was recorded on C. arvense (at six locations) and C. palustre (at one location). The probability of the presence of attack on C. arvense was positively correlated with the attack intensity on C. vulgare, suggesting that attack on C. arvense is a ‘spill-over effect’ occurring where seedheads of C. vulgare are in limited supply.

Bridging the Research-Implementation Gap in Weed Management on California Rangelands

Substantial gaps exist between weed management researchers and practitioners with respect to prompt exchange of knowledge between the two groups, hindering the implementation of effective management to solve weed problems. We conducted a survey between 2016 and 2018 among weed management practitioners (n = 259) across diverse ecoregions on California rangelands and collected essential information from practitioners for bridging the research-implementation gap. The information included management costs, high-priority weeds, and spatial scales and temporal changes in weed management. The management cost had a mean of $5.12 ha−1yr−1 with a large variance implying the uncertainty of this information. The percentage of annual budget dedicated to weed management explained about 30% of the variation in this cost. Moreover, this annual per-unit area cost decreased with increasing management area. The average size of rangeland managed by survey respondents was 1 256 ha. The top three high-priority weeds statewide were yellow starthistle (Centaurea solstitialis), medusahead (Taeniatherum caput-medusae), and all thistles combined. Medusahead and some thistle species remained on the top list in each ecoregion. Respondents overwhelmingly (80.9%) noted changes in weed problems in the past 5−10 yr, specifically citing greater weed pressure and changes in weed species. A significantly higher proportion of respondents from agencies and private businesses reported changes in weed problems than those from universities and nongovernmental organizations (NGOs), further underscoring the gap between practitioners and researchers. A majority of the respondents (75.3%) indicated the record-setting California drought had a negative effect on weed management, reducing treatment efficacy and favoring weeds over desirable species. Overall, our findings illustrate increasing challenges in weed management on California rangeland. These challenges call for adaptive management-research programs to increase cost-effectiveness of weed management and to swiftly and effectively respond to dynamic weed problems on large spatial and long temporal scales.

Effect of capitulum position and weevil infestation on seed production of threatened monocarpic perennial, Cirsium pitcheri

Cirsium pitcheri is a federally threatened, monocarpic perennial thistle species endemic to the Great Lakes region of the United States and Canada. Human habitat disturbances, lake level fluctuations and climate change have resulted in extensive declines of C. pitcheri populations. Seed predation by non-native weevil, Larinus planus, has also further exacerbated C. pitcheri population declines and reduced its projected time to extinction to less than 20 years. Given the widespread presence of L. planus throughout C. pitcheri’s range, studies that investigate its impacts are essential for understanding and predicting changes in the life histories and demographic rates of C. pitcheri populations. We present a two-year field study and common garden experiment that examine the relationship between C. pitcheri whole plant fecundity and capitulum position and assess the impacts of L. planus on C. pitcheri seed production. This study is part of an on-going population viability analysis and aims to inform C. pitcheri conservation and restoration efforts. Our results demonstrate that C. pitcheri mature seed production differs among capitulum positions and that the overall reproductive effort of C. pitcheri is reduced by L. planus. Terminal capitula being the largest and first to develop in C. pitcheri, produced the heaviest and greatest number of mature seeds across all capitulum positions. Capitula with evidence of weevil infestation, however, produced 60% fewer mature seeds and 40% fewer unfilled seeds that were also lighter than those without weevils. Evidence of weevil infestation was also primarily concentrated in secondary and tertiary capitula, which are produced at the tips of first- and second-order branches respectively. Along with information on capitulum contributions to C. pitcheri whole plant fecundity, our report presents one of the first accounts for the position-dependent oviposition of non-native weevil, L. planus, and its direct effects on C. pitcheri seed production.

Control of Nuttall's thistle in perennial grass pastures

AbstractNuttall's thistle (Cirsium nuttalli DC) is a biennial species that deters grazing during dry seasons in Florida when forage is limited. Although management of other thistle species has been extensively studied, information on Nuttall's thistle control is limited. Field studies were conducted to compare the effectiveness of aminopyralid, dicamba, and 2,4‐D for Nuttall's thistle control applied at two different timings (rosette vs. bolting). A second experiment was conducted to determine the most effective aminopyralid rate through field dose–response studies. Although control of bolting plants was initially greater than control of rosette thistle at 15 d after treatment (DAT), no differences were detected between growth stages at 30 and 60 DAT. Excellent control (>90%) was achieved at 60 DAT with both rates of dicamba + 2,4‐D [4.0 + 11.4 and 6.0 + 17.2 oz acid equivalent (ae) acre−1] and aminopyralid at 0.77 oz acre−1, whereas aminopyralid at 0.26 oz ae acre−1 and both rates of 2,4‐D (7.0 and 14.0 oz ae acre−1) provided 82, 80, and 78% control, respectively. The dose–response field experiment indicated that the aminopyralid effective dose required for 90% control (ED90) was 0.34 and 0.94 oz ae acre−1 for rosette and bolting thistle at 30 DAT, respectively. No difference between timings was detected at 60 DAT and the aminopyralid ED90 value was 0.27 oz acre−1. These data indicate that dicamba + 2,4‐D (6.0 + 17.2 oz ae acre−1) effectively controlled Nuttall's thistle; similar performance can be obtained with low aminopyralid rates (0.27 oz ae acre−1).

“Cardos” of two worlds: Transfer and resignification of the uses of thistles from the Iberian Peninsula to Argentina

“Thistles” constitute a group of prickly herbaceous plants included in the Cardueae tribe (Asteraceae), but in the popular sense that concept is frequently applied to other species of the same family, as well as to some Dipsacaceae, Bromeliaceae, Apiaceae or Cactaceae. Since antiquity, the cultivation and use of thistles for food and medicinal purposes has been well known in the Mediterranean cultures. The different popular knowledge could allow us to refer to a “thistle culture”. During the exploration of America, many of those species and their associated knowledge were transferred from the Old to the New World. In Argentina, several species of thistles, especially Cynara cardunculus , spread extensively throughout the pampas . From early times, they constituted a source of food and low quality fuel, and in several cases they were also employed in popular medicine, with diverse uses, some of which are still in practice. The local importance of some species is mentioned in gaucho literature, arts, and gastronomy. In the 20th century, a large production of artichokes from introduced crops that increased local agro-diversity was recorded in Argentina. This contribution summarizes some aspects of the transfer and re-signification of the thistle between the Iberian Peninsula and Argentina.

Anticancer activity and phytochemical composition of wild Gundelia�tournefortii

Artichoke-like wild thistles are often used in Palestinian cuisine. One of the most commercially recognized species of these wild edible thistles is Gundelia tournefortii, a common plant in the Mediterranean region. G. tournefortii, or 'Akoob' in Arabic, remains uncultivated, harvested wild by local populations and considered highly valuable due to its reputed health benefits. The present study aimed to investigate the anticancer effects of G. tournefortii on the human colon carcinoma HCT-116 cell line. Methanol and hexane extracts were identified to exert considerable antitumor activity against the HCT-116 cancer cell line, while the aqueous extract was inactive. The phytochemical profiles of the methanol and hexane extracts were investigated using gas chromatography-mass spectrometry. A total of 6 of the 27 natural compounds identified, including sitosterol, stigmasterol, lupeol, gitoxigenin, α-amyrin and artemisinin, have been previously validated as being active against cancerous cells. Therefore, the presence of these phytochemicals in G. tournefortii is of importance in its role in preventing and treating cancer.

Simultaneous determination of methoxyflavones in selected Korean thistles

Simultaneous determination of three methoxyflavones, namely, cirsimarin (1), hispidulin (2), and cirsimaritin (3) in selected Korean thistles was performed via reversed-phase high performance liquid chromatography system. Compound 1 was present in all the thistle species examined, whereas 2 and 3 were only detected in Cirsium japonicum and C. japonicum var. maackii (CJM). The concentration of compounds 1-3 in CJM varied according to the time of harvest. Plants collected in the spring (CJMS) and fall (CJMF) had the highest contents of 3 and 1, respectively. A lower content of 2 was observed in CJMF than in CJMS. This indicates that seasonal variation affects the flavonoid content of CJM. The results of this study show that CJM is an excellent source of compounds 1-3 and it can potentially be cultivated for industrial and pharmaceutical applications involving these compounds.

Development of specific SNP molecular marker from Thistle using DNA sequences of ITS region

Thistle is a perennial plant that is widely used for medicinal purposes. Information on the genetic diversity of thistle populations are great important for their conservation and germ plasmic utilization. Although thistle is an important medicinal plant species registered in South Korea, no molecular markers are currently available to distinguish them from other similar species from different countries. In this study, we developed single nucleotide polymorphism (SNP) markers derived from the nuclear ribosomal DNA internal transcribed spacer (ITS) regions of genomic sequences to identify distinct Korean-specific thistle species via an amplification refractory mutation system (ARMS)-PCR and high resolution melting (HRM) curve analyses. We performed molecular authentication of four different kinds of thistle species from different regions using DNA sequences in the ITS intergenic region. We also developed a quantitative PCR assay using species-specific ITS primers, which allowed us to estimate the ratio of Korean-specific thistle species using varying ratios of mixed genomic DNA templates from the two species. The SNP markers developed in this study are useful for rapidly identifying specific thistle species from different countries.

Biological Control of Musk Thistle (Asteraceae) by the WeevilRhinocyllus conicus(Coleoptera: Curculionidae) and its Establishment on Nontarget Thistles in Georgia, USA1

Abstract The weevil Rhinocyllus conicus Froelich was introduced in Georgia, USA as a biological control agent of musk thistle, Carduus nutans L. (Asteraceae) in 1991. Musk thistle populations and R. conicus infestations were monitored over 10 yr at four sites in central Georgia. Musk thistle populations declined substantially as R. conicus populations increased at all sites, but thistle infestations remained problematic at some sites. A laboratory cage study found that R. conicus would lay eggs on flower buds of yellow thistle, Cirsium horridulum Michaux, bull thistle Cirsium vulgare (Savi) Tenore, and blessed milkthistle, Silybum marianum (L.) Gaertner in no-choice and choice tests with and without Ca. nutans. Carduus nutans was preferred over the other thistle species, but the other thistle species were acceptable for oviposition by R. conicus. One or more mixed field infestations of musk thistle and yellow, bull, or blessed milkthistles were sampled for R. conicus infestation. Rhinocyllus conicus was n...

The potential of native species as bioenergy crops on trace-element contaminated Mediterranean lands

The establishment of energy crops could be an option for the management of degraded and contaminated lands, where they would not compete with food production for land use. Here, we aimed to explore the potential of certain native Mediterranean species for the revegetation of contaminated lands for energy production purposes. A field survey was conducted in a trace-element (TE) contaminated area from SW Spain, where the patterns of biomass production, TE accumulation and the calorific value of some thistle species were analyzed along a soil contamination gradient. In a greenhouse experiment the response of two thistle species (Cynara cardunculus and Silybum marianum) and the shrub Dittrichia viscosa to soil contamination was assessed, as well as the effects of these species on some soil microbial parameters involved in nutrient cycling (enzyme activities and arbuscular mycorrhizal colonization in roots). Silybum marianum was able to colonize highly contaminated soils. Its aboveground biomass accumulated Cd and had a relatively high calorific value; this value was similar in biomass obtained from both heavily and moderately contaminated soils. Greenhouse experiment confirmed that S. marianum biomass production and calorific value is scarcely affected by soil contamination. In addition, some soil enzyme activities were clearly enhanced in the S. marianum rhizosphere. Dittrichia viscosa is another promising species, given its capacity to produce a high biomass with appreciable calorific value in acid contaminated soils. Germination of both species was hampered in the acid contaminated soil, and therefore soil pH correction would have to be accomplished before establishing these species on extremely acid soils. Further assessment of the risk of transfer of Cd and other TE to the food chain would be needed to confirm the suitability of these species for the revegetation of contaminated lands with energy production purposes.

Larinus turbinatus Gyllenhal (Coleoptera: Curculionidae: Lixinae), a Eurasian Weevil New to North America with a Summary of Other Adventive Larinus in North America and a Key to Species

Abstract. Larinus turbinatus Gyllenhal, a Palearctic weevil that feeds on thistle species of the genera Cirsium and Carduus (Asteraceae: tribe Cardueae), is newly reported for North America. It was first collected by sweep net sampling of flowers of pasture thistle Cirsium pumilum (Nutt.) Spreng. at Fort Indiantown Gap, Lebanon County, Pennsylvania in late July 2011 and specimens were hand-collected from field thistle Cirsium discolor (Muhl. exWilld.) Spreng. at Gettysburg National Park, Adams County, Pennsylvania in late August 2012. This is the first published record of this Old World species in the Western Hemisphere. At present, five species of the genus Larinus are known as introduced into North America. These are L. turbinatus Gyllenhal, L. carlinae (Olivier) (known formerly as L. planus), L. curtus Hochhuth, L. obtusus Gyllenhal, and L. minutus Gyllenhal. Brief summaries of their hosts, distributions, biology and a key for their separation are provided.

Flower heads of Onopordum tauricum Willd. and Carduus acanthoides L. - source of prebiotics and antioxidants

The carbohydrate composition (inulin and sugars) and antioxidant potential of 95% ethanol and subsequent water extracts from flower heads of Carduus acanthoides L. and Onopordum tauricum Willd. grown in Bulgaria were investigated. The total fructans content in both thistle species was analyzed by ketose-specific assay, while individual inulin and sugars content was defined by HPLC-RID method. The total phenolic content and the antioxidant capacity of the studied extracts were also examined as the antioxidant potential was determined by four in vitro assays (DPPH, ABTS, FRAP and CUPRAC). O. tauricum Willd. flower heads were evaluated for the first time as a rich source of prebiotics and total phenols. Higher fructans content was found in the water extracts, while the ethanol extracts possessed better antioxidant activity.Key words: antioxidants; extracts; inulin; fructooligosacharides; thistles