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At least 55 records · Page 3Linked to original sources
PubMed2002

Physiological variation in populations of Ranunculus repens L. (creeping buttercup) from the temporary limestone lakes (turloughs) in the west of Ireland.

A dissected-leaved form of Ranunculus repens L. occurs in the temporary limestone lakes (turloughs) across the west of Ireland. Turloughs fill with groundwater for up to 8 months of the year. Under experimental conditions, these turlough populations demonstrated a higher rate of aerial and submerged photosynthesis than populations of the more typical broad-leaved ruderal form. The turlough populations also had higher rates of stomatal conductance and exhibited a higher stomatal index on the upper leaf surface and a lower index on the lower leaf surface than the ruderal populations. Neither population could utilize bicarbonate to any great extent, with rates of photosynthesis under submerged conditions being only 5 % of aerial rates. Respiration under submerged conditions was significantly higher in the turlough populations than in ruderal populations, and it is hypothesized that the more dissected leaf shape of the turlough population may have a thinner boundary layer and thus enhance gas exchange in submerged conditions.

Adaptation, Physiological↗
PubMed1991

Ethylene Promotes Elongation Growth and Auxin Promotes Radial Growth in Ranunculus sceleratus Petioles.

Submergence induces elongation in the petioles of Ranunculus sceleratus L., after a rise in endogenous ethylene levels in the tissue. Petioles of isolated leaves also elongate 100% in 24 hours when treated with ethylene gas, without a change in the radius. Application of silver thiosulfate, aminoethoxyvinylglycine (AVG), abscisic acid (ABA), or methyl jasmonate inhibits this elongation response. Gibberellic acid treatment promotes ethylene-induced elongation, without an effect on the radius. Indoelastic acid (IAA) induces radial growth in the petioles, irrespective of the presence or absence of added ethylene. High concentrations of IAA will also induce elongation growth, but this is largely due to auxin-induced ethylene synthesis; treatment with silver thiosulfate, AVG, ABA, or methyl jasmonate inhibit this auxin-promoted elongation growth. However, the radial growth induced by IAA is not affected by gibberellic acid, and not specifically inhibited by ABA, methyl jasmonate, silver thiosulfate, or AVG. These results support the idea that petiole cell elongation during "accommodation growth" can be separated from radial expansion. The radial expansion may well be regulated by IAA. However, effects of high levels of IAA are probably anomalous, since they do not mimic normal developmental patterns.

Journal Article↗
PubMed2005

A threefold genetic allee effect: population size affects cross-compatibility, inbreeding depression and drift load in the self-incompatible Ranunculus reptans.

A decline in population size can lead to the loss of allelic variation, increased inbreeding, and the accumulation of genetic load through drift. We estimated the fitness consequences of these processes in offspring of controlled within-population crosses from 13 populations of the self-incompatible, clonal plant Ranunculus reptans. We used allozyme allelic richness as a proxy for long-term population size, which was positively correlated with current population size. Crosses between plants of smaller populations were less likely to be compatible. Inbreeding load, assessed as the slope of the relationship between offspring performance and parental kinship coefficients, was not related to population size, suggesting that deleterious mutations had not been purged from small populations. Offspring from smaller populations were on average more inbred, so inbreeding depression in clonal fitness was higher in small populations. We estimated variation in drift load from the mean fitness of outbred offspring and found enhanced drift load affecting female fertility within small populations. We conclude that self-incompatibility systems do not necessarily prevent small populations from suffering from inbreeding depression and drift load and may exacerbate the challenge of finding suitable mates.

Alleles↗
PubMed2000

RAPD variation among and within small and large populations of the rare clonal plant Ranunculus reptans (Ranunculaceae).

In the pre-alpine region of Europe numbers and sizes of populations of the clonal lake shore plant Ranunculus reptans have declined because of the regulation of lake water levels. We investigated genetic variation among and within 17 populations of different size (cover 1-10 000 m) in R. reptans with RAPD (random amplified polymorphic DNA) profiles. We sampled 127 rosettes in 14 populations at Lake Constance and three populations at or near Lake Como. There was significant genetic variation between plants from the two lake regions (5.9%, analysis of molecular variance [AMOVA], P < 0.001), among populations within lake regions (20.4%, P < 0.001), and within populations (73.7%, P < 0.001). Under the assumptions of Wright's island model the variation among populations corresponds to a gene flow of N(e)m = 0.70. Within the 14 Lake Constance populations we detected significant genetic variation among subpopulations separated by only a few metres (4.0% of the within-population variation; P < 0.05). Molecular variance was 24% smaller in small populations covering <100 m area than in larger ones (P < 0.03), indicating that samples from large populations were genetically more variable than samples representing comparable areas of smaller populations. We conclude that gene flow among populations is very limited and that genetic drift has caused reduced genetic variability of smaller populations. Conservation of genetic variability in R. reptans requires persistence of large and also of small populations (because of population differentiation), and it could be enhanced by increasing the size of small populations (to counter genetic drift).

Journal Article↗
PubMed2000

Costs of plasticity in foraging characteristics of the clonal plant Ranunculus reptans.

In clonal plants, evolution of plastic foraging by increased lengths of leaves and internodes under unfavourable conditions may be constrained by costs and limits of plasticity. We studied costs and limits of plasticity in foraging characteristics in 102 genotypes of the stoloniferous herb Ranunculus reptans. We grew three replicates of each genotype with and three without competition by the naturally co-occuring grass Agrostis stolonifera. We used regression and correlation analyses to investigate potential costs of plasticity in lengths of leaves and stolon internodes, developmental instability costs of these traits, and a developmental range limit of these traits. We used randomization procedures to control for spurious correlations between parameters calculated from the same data. Under competition the number of rosettes, rooted rosettes, and flowers was 58%, 40%, and 61% lower, respectively, than in the absence of competition. Under competition lengths of leaves and stolon internodes were 14% and 6% smaller, respectively, than in the absence of competition. We detected significant costs of plasticity in stolon internode length in the presence of competition when fitness was measured in terms of the number of rosettes and the number of flowers (selection gradients against plasticity were 0.250 and 0.214, respectively). Within-environment variation (SD) in both foraging traits was not positively correlated with the corresponding plasticity, which indicates that there were no developmental instability costs. More plastic genotypes did not have less extreme trait values than less plastic genotypes for both foraging traits, which indicates that there was no developmental range limit. We conclude that in R. reptans costs of plasticity more strongly constrain evolution of foraging in the horizontal plane (i.e., stolon internode length) than in the vertical plane (i.e., leaf length).

Adaptation, Physiological↗
PubMed1994

[Pharmacognosy of Ranunculus chinensis Bge].

Ranunculus chinensis is a folk herb popular in some districts of Yunnan Province. The paper deals with the plant resources, macroscopic shape and microscopic characteristics of this herb so as to provide referential information for clinics, research institutes and herbal market.

Drugs, Chinese Herbal↗
PubMed1995

[Effect of the active components of Ranunculus ternatus Thunb. on the inductive production of tumor necrosis factors by macrophages].

The authors set up a screening system for the detection of TNF inducers. By using this model 36 traditional Chinese medical herbs from 28 families were studied. Seven herbs from 7 families were found to be active in the TNF induction. Among them Ranunculus Ternatus (RT) is the best one. The active components of RT were isolated from the crude extract by solvent extraction and column chromatography. Eleven fractions were obtained. RT-A2, one of the active components, is a white crystal and its IR spectrum is similar to Standard Infrared Grating Spectra No. 28344K. Therefore, RT-A2 may be identified as a fatty acid (palmitic acid). Its optimum dose of inducing TNF is 50 micrograms/ml in vitro. TNF induced in the cell culture was demonstrated by monoclone antibody neutralizing test.

Animals↗
PubMed2005

[Therapeutic uses for Asian yellow-flowered crowfoot, genus Ranunculus: the case of Blastoestimulina].

Asian yellow-flower crowfoot is a plant which has been used for therapeutic purposes for more than 3000 years. Its main active ingredients are asiaticóside and madecasóside which give it a cicatrizing action as well as being a tonic for the blood. At present time, Asian yellow-flower crowfoot extract is indicated to treat ulcers, sores, scabs, and some types of burns. It is also used as a secondary helping agent to treat surgical wounds and to help skin grafts take root. Its use in the form of vaginal ovules make it be an appropriate treatment for some vaginal diseases. This extract is currently found in diverse medical preparations under the trade name "Blastoestimulina". Numerous studies are underway in the scientific field with the objective of discovering new therapeutic uses for this plant.

Burns↗