|
| | 1. |
2007 Jan 26 |
Intra-plant variation in nectar sugar composition in two Aquilegia species (Ranunculaceae): contrasting patterns under field and glasshouse conditions.
Canto A, Pérez R, Medrano M, Castellanos MC, Herrera CM
Ann. Bot. 2007 Apr;99(4):653-60. Epub 2007 Jan 26.
Abstract
BACKGROUND AND AIMS: Intra-specific variation in nectar chemistry under natural conditions has been only rarely explored, yet it is an essential aspect of our understanding of how pollinator-mediated selection might act on nectar traits. This paper examines intra-specific variation in nectar sugar composition in field and glasshouse plants of the bumblebee-pollinated perennial herbs Aquilegia vulgaris subsp. vulgaris and Aquilegia pyrenaica subsp. cazorlensis (Ranunculaceae). The aims of the study are to assess the generality of extreme intra-plant variation in nectar sugar composition recently reported for other species in the field, and gaining insight on the possible mechanisms involved. METHODS: The proportions of glucose, fructose and sucrose in single-nectary nectar samples collected from field and glasshouse plants were determined using high performance liquid chromatography. A hierarchical variance partition was used to dissect total variance into components due to variation among plants, flowers within plants, and nectaries within flowers. KEY RESULTS: Nectar of the two species was mostly sucrose-dominated, but composition varied widely in the field, ranging from sucrose-only to fructose-dominated. Most intra-specific variance was due to differences among nectaries of the same flower, and flowers of the same plant. The high intra-plant variation in sugar composition exhibited by field plants vanished in the glasshouse, where nectar composition emerged as a remarkably constant feature across plants, flowers and nectaries. CONCLUSIONS: In addition to corroborating the results of previous studies documenting extreme intra-plant variation in nectar sugar composition in the field, this study suggests that such variation may ultimately be caused by biotic factors operating on the nectar in the field but not in the glasshouse. Pollinator visitation and pollinator-borne yeasts are suggested as likely causal agents.
[Pubmed: 17259227]
| | 2. |
2009 Dec |
Complementary and alternative medicine use among long-term lymphoma survivors: a pilot study.
Habermann TM, Thompson CA, LaPlant BR, Bauer BA, Janney CA, Clark MM, Rummans TA, Maurer MJ, Sloan JA, Geyer SM, Cerhan JR
Am. J. Hematol. 2009 Dec;84(12):795-8.
Abstract
No published survey has specifically addressed the beliefs, knowledge, and usage of complementary and alternative medicine (CAM) in long-term (5-20 years) lymphoma survivors alone. In this pilot project, 95 subjects were randomly selected from a population of 2,475 long-term lymphoma survivors and mailed a questionnaire. The median time from lymphoma diagnosis to completion of the questionnaire was 11 years (range 6-20). Overall, 68% (95% CI: 54-80%) of the long-term lymphoma survivors reported that they have used CAM, a rate higher than the estimated usage rate reported for the general population The most commonly used modalities were chiropractic (39%, 95% CI: 27-53%) and massage therapy (21%, 95% CI: 12-34%). Less than 10% used meditation (5%, 95% CI: 1-15%) and relaxation (7%, 95% CI: 2-17%). In terms of common herbal usage, 5% (95% CI: 1-15%) had used St. John's Wort and 7% (95% CI: 2-17%) had used shark cartilage. Although none of the patients reported that CAM usage was directed specifically towards treating their lymphoma, 4% (95% CI: 0-12%) of patients reported that CAM could cure cancer, and 14% (95% CI: 6-26%) reported that CAM could increase their feeling of control over their health. This pilot study suggests that long-term lymphoma survivors appear to use CAM at a rate higher than the general population. The use of potential agents of risk by the survivors and the lack of access to potentially beneficial modalities highlights the need for further study of CAM in this population.
[Pubmed: 19894247]
| | 3. |
2009 Aug |
Nectar and pollination drops: how different are they?
Nepi, von Aderkas, Wagner, Mugnaini, Coulter, Pacini
Ann Bot 2009 Aug;104(2):205-219.
Abstract
Pollination drops and nectars (floral nectars) are secretions related to plant reproduction. The pollination drop is the landing site for the majority of gymnosperm pollen, whereas nectar of angiosperm flowers represents a common nutritional resource for a large variety of pollinators. Extrafloral nectars also are known from all vascular plants, although among the gymnosperms they are restricted to the Gnetales. Extrafloral nectars are not generally involved in reproduction but serve as ‘reward’ for ants defending plants against herbivores (indirect defence).
[Pubmed: 19477895]
| | 4. |
2000 Sep |
6'-O-Coumaroylaloesin from Aloe castanea--a taxonomic marker for Aloe section Anguialoe.
van Heerden FR, Viljoen AM, van Wyk BE
Phytochemistry. 2000 Sep;55(2):117-20.
Abstract
The structure of 6'-O-coumaroylaloesin [2-acetonyl-8-(6-O-coumaroyl-beta-D-glucopyranosyl)-7-hydrox y-5-methylchromone], a mono-ester chromone derivative in which only the 6-position of the glucosyl moiety is esterified, was determined by spectroscopic methods. The compound is a unique chemotaxonomic character restricted to the six species in Aloe section Anguialoe.
[Pubmed: 11065286]
|
|
