Nectar Sugars in Proteaceae: Patterns and Processes

1998 ◽  
Vol 46 (4) ◽  
pp. 489 ◽  
Author(s):  
Susan W. Nicolson ◽  
Ben-Erik Van Wyk
Keyword(s):  
Diagnostic Value ◽  
Floral Nectar ◽  
Ecological Processes ◽  
Generic Level ◽  
Plant Phylogeny ◽  
Physiological Processes ◽  
Pentose Sugar ◽  
Flower Age ◽  
Nectar Sugar ◽  
Patterns And Processes

The nectar sugar composition is presented for 147 species from 16 genera of South African and Australian Proteaceae. Patterns associated with flower age, different plants and populations, plant phylogeny and pollination have been examined. In addition to the usual three nectar sugars (sucrose, fructose and glucose), the nectar of Protea and Faurea contains the pentose sugar xylose at concentrations of up to 39% of total sugar. Xylose has not previously been reported from floral nectar and is absent from the nectar of Adenanthos, Banksia, Brabejum, Dryandra, Grevillea, Hakea, Lambertia, Leucospermum, Macadamia, Mimetes, Orothamnus, Paranomus, Stenocarpus and Telopea. Most genera and species have hexose-dominant nectar, but within the large genera Banksia, Grevillea, Leucospermum and Protea some of the seemingly more derived species have sucrose-dominant nectar. This interesting dichotomy of low versus high sucrose is of diagnostic value at the species level and indicative of phylogenetic relationships within the larger genera. At the generic level, the presence of xylose is a convincing synapomorphy for Protea and Faurea. Studies of physiological processes (e.g. enzyme activities) and ecological processes (e.g. pollination) may help to explain some of the conservative and taxonomically interesting nectar sugar patterns.

Nectar secretion strategy in three Japanese species: changes in nectar volume and sugar concentration dependent on flower age and flowering order

Botany ◽  
2008 ◽  
Vol 86 (4) ◽  
pp. 337-345 ◽  
Author(s):  
Shinya Kato ◽  
Satoki Sakai
Keyword(s):  
Reproductive Success ◽  
Early Flowering ◽  
Sugar Concentration ◽  
Nectar Secretion ◽  
Floral Nectar ◽  
Japanese Species ◽  
Nectar Volume ◽  
Flower Age ◽  
Nectar Sugar ◽  
The Mean

We explored how changes in nectar volume and nectar sugar concentration depend on flower age and flowering order in Gentiana triflora Pallas var. japonica (Kusnez.) Hara, Lobelia sessilifolia Lamb., and Hemerocallis middendorffii Trautv. et Mey. var. esculenta (Koidz.) Ohwi. In G. triflora var. japonica and H. middendorffii var. esculenta, change in nectar volume was small, whereas larger changes in nectar sugar concentration occurred depending on flower age. In L. sessilifolia, both the mean nectar volume and nectar sugar concentration clearly decreased with flower age. In all species, the mean nectar volume of the early-flowering group per plant was high. In terms of the change in sex allocation, the investment in male and female organs of the early-flowering group was high in G. triflora var. japonica and L. sessilifolia. We suggest that plants of G. triflora var. japonica and H. middendorffii var. esculenta secrete floral nectar for up to several days to sustain nectar volume to keep attracting pollinators while simultaneously reducing resource usage. Greater nectar secretion in the early-flowering group, in which flowers have more pollen and ovules, may contribute to greater reproductive success and may be effective for pollinators in learning the location of the plants and flowers. In addition, learning by pollinators should result in increased reproductive success of the later blooming flowers.

scholarly journals Salvage of floral resources through re-absorption before flower abscission

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Graham H. Pyke ◽  
Zong-Xin Ren ◽  
Judith Trunschke ◽  
Klaus Lunau ◽  
Hong Wang
Keyword(s):  
Floral Resources ◽  
Floral Nectar ◽  
Nectar Volume ◽  
Flower Colours ◽  
Nectar Concentration ◽  
Nectar Sugar ◽  
Biochemical Mechanisms ◽  
Floral Resource ◽  
Almost All

Abstract Plants invest floral resources, including nectar and pigment, with likely consequent reproductive costs. We hypothesized that plants, whose flowers abscise with age, reabsorb nectar and pigment before abscission. This was tested with flowers of Rhododendron decorum, which has large, conspicuous white flowers that increasingly abscise corollas as flowers age. As this species is pollinated by bees, we also hypothesized that nectar concentration would be relatively high (i.e., > 30% wt/vol) and petals would contain UV-absorbing pigment. Floral nectar volume and concentration were sampled on successive days until abscission (up to ten days old, peak at five days) and for sub-sample of four-day-old flowers. Flowers just abscised were similarly sampled. Flower colours were measured using a modified camera, with recordings of spectral reflectance for abscised and open non-abscised flowers. Pigment content was summed values of red, green, blue channels of false color photos. As expected, flowers reabsorbed almost all nectar before abscission, separately reabsorbing nectar-sugar and nectar-water, and petals contained UV-absorbing pigment. However, flowers did not reabsorb pigment and nectar-concentration was < 30% wt/vol. That flowers reabsorb nectar, not pigment, remains unexplained, though possibly pigment reabsorption is uneconomical. Understanding floral resource reabsorption therefore requires determination of biochemical mechanisms, plus costs/benefits for individual plants.

ORNITHOPHILY AMONG THE HAWAIIAN LOBELIOIDEAE (CAMPANULACEAE): EVIDENCE FROM FLORAL NECTAR SUGAR COMPOSITIONS

1986 ◽  
Vol 73 (11) ◽  
pp. 1613-1619 ◽  
Author(s):  
Thomas G. Lammers ◽  
C. Edward Freeman
Keyword(s):  
Floral Nectar ◽  
Nectar Sugar

FLORAL NECTAR SUGAR COMPOSITION AND POLLINATOR TYPE AMONG NEW WORLD GENERA IN TRIBE ANTIRRHINEAE (SCROPHULARIACEAE)

1988 ◽  
Vol 75 (7) ◽  
pp. 971-978 ◽  
Author(s):  
Wayne J. Elisens ◽  
C. Edward Freeman
Keyword(s):  
New World ◽  
Sugar Composition ◽  
Floral Nectar ◽  
Nectar Sugar Composition ◽  
Nectar Sugar

scholarly journals Longevity and ageing: appraising the evolutionary consequences of growing old

2005 ◽  
Vol 361 (1465) ◽  
pp. 119-135 ◽  
Author(s):  
Michael B Bonsall
Keyword(s):  
Life History ◽  
Biological Diversity ◽  
Species Coexistence ◽  
Life History Strategies ◽  
Life History Trait ◽  
Future Research ◽  
Ecological Processes ◽  
Physiological Processes ◽  
Trade Offs ◽  
Evolutionary Consequences

Senescence or ageing is an increase in mortality and/or decline in fertility with increasing age. Evolutionary theories predict that ageing or longevity evolves in response to patterns of extrinsic mortality or intrinsic damage. If ageing is viewed as the outcome of the processes of behaviour, growth and reproduction then it should be possible to predict mortality rate. Recent developments have shown that it is now possible to integrate these ecological and physiological processes and predict the shape of mortality trajectories. By drawing on the key exciting developments in the cellular, physiological and ecological process of longevity the evolutionary consequences of ageing are reviewed. In presenting these ideas an evolutionary demographic framework is used to argue how trade-offs in life-history strategies are important in the maintenance of variation in longevity within and between species. Evolutionary processes associated with longevity have an important role in explaining levels of biological diversity and speciation. In particular, the effects of life-history trait trade-offs in maintaining and promoting species diversity are explored. Such trade-offs can alleviate the effects of intense competition between species and promote species coexistence and diversification. These results have important implications for understanding a number of core ecological processes such as how species are divided among niches, how closely related species co-occur and the rules by which species assemble into food-webs. Theoretical work reveals that the proximate physiological processes are as important as the ecological factors in explaining the variation in the evolution of longevity. Possible future research challenges integrating work on the evolution and mechanisms of growing old are briefly discussed.

scholarly journals Micro-organisms behind the pollination scenes: microbial imprint on floral nectar sugar variation in a tropical plant community

2012 ◽  
Vol 110 (6) ◽  
pp. 1173-1183 ◽  
Author(s):  
A. Canto ◽  
C. M. Herrera
Keyword(s):  
Plant Community ◽  
Floral Nectar ◽  
Tropical Plant ◽  
Nectar Sugar ◽  
Micro Organisms

Floral Nectar Sugar Compositions of Some South and Southeast Asian Species

Biotropica ◽  
1991 ◽  
Vol 23 (4) ◽  
pp. 568 ◽  
Author(s):  
C. Edward Freeman ◽  
Richard D. Worthington ◽  
Margaret S. Jackson
Keyword(s):  
Southeast Asian ◽  
Floral Nectar ◽  
Asian Species ◽  
Nectar Sugar

scholarly journals Pollinator adaptation and the evolution of floral nectar sugar composition

2016 ◽  
Vol 30 (1) ◽  
pp. 112-127 ◽  
Author(s):  
S. Abrahamczyk ◽  
M. Kessler ◽  
D. Hanley ◽  
D. N. Karger ◽  
M. P. J. Müller ◽  
...  
Keyword(s):  
Sugar Composition ◽  
Floral Nectar ◽  
Nectar Sugar Composition ◽  
Nectar Sugar
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