Nectar collected with microcapillary tubes is less concentrated than total nectar in flowers with small nectar volumes

2011 ◽  
Vol 59 (6) ◽  
pp. 593 ◽  
Author(s):  
Sophie Petit ◽  
Nadia Rubbo ◽  
Russell Schumann

Previous research indicated that microcapillary tubes greatly underestimated sugar present in flowers with low nectar volumes, but it was unclear whether tubes missed liquid nectar or whether sugar concentration in nectar they collected did not represent total sugar concentration in a flower. We determined the suitability of microcapillary tubes to estimate the energetic value of Acrotriche patula R.Br. (Ericaceae) nectar from total sugar mass. We collected a standing crop of nectar from individual flowers with microcapillary tubes and subsequently washed the flowers to recover putatively any residual sucrose, glucose, and fructose. We assessed microcapillary nectar volume as a predictor for total sugar mass in a flower by regression analysis, identified the percentage of sugar missed by microcapillary tubes, and compared sugar ratios between microcapillary samples and total nectar. Nectar volume collected with microcapillary tubes cannot be used to predict total nectar sugar contents in a flower. Microcapillary tubes missed 71% of the floral sugar on average, but not a large volume, indicating that sugar is not evenly distributed in a flower’s nectar. Proportions of different sugars did not differ significantly between microcapillary samples and total samples. Animals with different tongue morphologies and feeding behaviours may obtain different energetic rewards from the same flower with low nectar volume. Variation in a flower’s nectar at one point in time is likely to favour the generalisation of pollination systems.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 591a-591 ◽  
Author(s):  
Don R. LaBonte ◽  
David H. Picha

Six sweetpotato cultivars were evaluated for changes in individual sugar concentration, dry weight, and alcohol insoluble solids (AIS) during growth and development. Measurements were taken at weekly intervals from 7 to 21 weeks after transplanting. Sucrose, the major sugar during all stages of development, generally increased in concentration throughout development for `Heart-o-gold', `Travis', and `Jewel', but peaked at 17 weeks for `Beauregard' and `Whitestar'. The high-dry matter white flesh cultivars of `Rojo Blanco' and `Whitestar' contained the lowest sucrose concentration. The monosaccharides glucose and fructose generally decreased in concentration up to 17 weeks in 4 of 6 cultivars, followed by an increase from 17 to 21 weeks in all cultivars. Glucose concentration was marginally greater than fructose at all stages of development in each cultivar. Little or no increase in total sugar concentration occurred during development in `Whitestar' and `Rojo Blanco'. A substantial increase in total sugars occurred during development with `Jewel', `Beauregard', `Heart-o-gold' and `Travis'. Cultivars differed widely in their individual sugar concentrations during development. Percent dry matter increased in all cultivars from 7 to 14 weeks. Dry matter and AIS decreased during the later stages of development.



2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Dongxu Zhang ◽  
Yee Ling Ong ◽  
Zhi Li ◽  
Jin Chuan Wu

Getting high sugar concentrations in lignocellulosic biomass hydrolysate with reasonable yields of sugars is commercially attractive but very challenging. Two-step acid-catalyzed hydrolysis of oil palm empty fruit bunch (EFB) was conducted to get high sugar concentrations in the hydrolysate. The biphasic kinetic model was used to guide the optimization of the first step dilute acid-catalyzed hydrolysis of EFB. A total sugar concentration of 83.0 g/L with a xylose concentration of 69.5 g/L and a xylose yield of 84.0% was experimentally achieved, which is in well agreement with the model predictions under optimal conditions (3% H2SO4and 1.2% H3PO4, w/v, liquid to solid ratio 3 mL/g, 130°C, and 36 min). To further increase total sugar and xylose concentrations in hydrolysate, a second step hydrolysis was performed by adding fresh EFB to the hydrolysate at 130°C for 30 min, giving a total sugar concentration of 114.4 g/L with a xylose concentration of 93.5 g/L and a xylose yield of 56.5%. To the best of our knowledge, the total sugar and xylose concentrations are the highest among those ever reported for acid-catalyzed hydrolysis of lignocellulose.



2014 ◽  
Vol 70 (1) ◽  
Author(s):  
K. H. Mah ◽  
H. W. Yussof ◽  
N. A. Jalanni ◽  
M. N. Abu Seman ◽  
N. Zainol

Xylose is an abundant raw material coexists with other sugars that can be turned into useful products, such as ethanol, xylitol and 2, 3-butanediol by microorganism such as yeasts, bacteria, and mycelial fungi. However, more than 80 % of the production cost of these products comes solely from the production of xylose. Presently, the separation of xylose from hemicellulose hydrolysate relies on chromatographic separation alone. The use of nanofiltration membrane may offer alternative in recovering xylose due to the differences in size compared to other sugars. The aim of this study is to evaluate the ability of membrane developed by interfacial polymerization reaction between triethanolamine (TEOA) (6 % w/v) and tri-mesoyl chloride (TMC) (0.15 % w/v) as monomers on polyethersulfone (PES) microporous substrate to separate xylose from glucose. In this study, factors affecting the process, namely pressure, concentration of total sugars in solution, and composition of monosaccharides in total sugar, were investigated using two-level factorial analysis. The experiment was performed using Amicon Milipore stirred cell (Model 8200) with constant stirring speed at 300 rpm and temperature at ambient. The glucose and xylose concentration was quantified using high performance liquid chromatography (HPLC). It is found that the developed nanofiltration membrane has the ability to separate xylose from glucose.The analysis of the experimental response revealed that the total sugar concentration and composition ratio of xylose: glucose had significant interactive effect on xylose separation factor. Overall from the present study, it can be concluded that nanofiltration has high potential to replace currently in use chromatographic method in xylose separation.



Botany ◽  
2008 ◽  
Vol 86 (4) ◽  
pp. 337-345 ◽  
Author(s):  
Shinya Kato ◽  
Satoki Sakai

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.



HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 531-532 ◽  
Author(s):  
Richard J. Campbell ◽  
Richard D. Fell ◽  
Richard P. Marini

Flowering spurs located at interior and exterior canopy positions of `Stay-man' and `Delicious' apple (Malus domestics Borkh.) trees were girdled and/or defoliated to determine the influence on nectar production and composition. Nectar volume was less at exterior than interior canopy positions for `Delicious', but not for `Stayman'. Girdling suppressed nectar production by 92% and reduced the sugar concentration of the remaining nectar. Defoliation of nongirdled spurs had no effect on nectar sugar concentration, but defoliation of girdled spurs reduced nectar sugar concentration by 24%. Relative percentages of sucrose, glucose, and fructose, and the sucrose: hexose ratio were unaffected by any treatment. Nectar production of nongirdled spurs did not depend on the presence of spur leaves.



HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 825D-825
Author(s):  
Durel J. Romaine ◽  
Don R. LaBonte

Seven compositionally diverse sweetpotato lines were examined for changes in individual sugar concentrations at harvest (green), after curing (7 days at 90% RH and 29.5C), and after 4 and 8 weeks of cold storage (16C) to determine the relationship between raw and cooked root sugar composition. Raw root sucrose concentrations at harvest in two dessert types, `L91-80' and `Heart-O-Gold', were at least 22% higher than other dessert types, such as `Beauregard' and `Jewel', and 26% higher than white starchy types (`Rojo Blanca' and `White Star'). The sucrose concentration remained correspondingly higher for these two lines when baked or microwaved. Total sugar concentration was not significantly correlated between raw vs. baked or microwaved roots. The major sugar in most baked and microwaved roots was maltose, accounting for 18% to 93% of the total sugars. `L91-80' behaved differently from other lines during microwaving, where sucrose was the major sugar. The total sugar concentration of `L91-80' and `Heart-O-Gold' were not statistically greater after baking and microwaving for all dates, including the white, starchy types. These results suggest the need to further evaluate the relative importance of individual sugar concentrations on consumer preference.



2010 ◽  
Vol 26 (4) ◽  
pp. 373-379 ◽  
Author(s):  
Tadeu J. Guerra ◽  
Gustavo Q. Romero ◽  
Woodruff W. Benson

Abstract:Nectarivorous flower mites can reduce the volume of nectar available to pollinators. The effects of the flower mite Proctolaelaps sp. on nectar availability in flowers of a melittophilous bromeliad Neoregelia johannis (Bromeliaceae) was evaluated in a coastal rain forest in south-eastern Brazil. In a randomized block experiment utilizing 18 flower pairs, one per bromeliad ramet, pollinators (Bombus morio) and mites were excluded, and then nectar volume, sugar concentration and sugar mass were quantified over the anthesis period. Mites significantly reduced nectar volume early in the morning (6h00–8h00), but not later (10h00–12h00). Mites decreased total volume of nectar available up to 22%. Sugar concentration in nectar was higher earlier in the morning, and decreased between 10h00–12h00. The pronounced consumption of nectar by mites during the period of higher sugar concentration reduced the total amount of sugar available to pollinators by 31%. This is the first study showing that flower mites decrease nectar rewards in a melittophilous plant. Because nectar volume by itself incompletely describes nectar production rates and the effects of nectar removal by flower mites on the availability of sugar, our study highlights the inclusion of sugar content in future studies assessing the effects of thieves on nectar production rates.



2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Graham H. Pyke ◽  
Zong-Xin Ren ◽  
Judith Trunschke ◽  
Klaus Lunau ◽  
Hong Wang

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.



2018 ◽  
Vol 7 (3) ◽  
pp. 93
Author(s):  
Yemima Dwi Gita Sembiring ◽  
Komang Ayu Nocianitri ◽  
Agus Selamet Duniaji

This research was conducted to determine the effect of sugar contentration and fermentation time to the charateristics of mung bean probiotic drink with the addition of Lactobacillus rhamnosus SKG 34. The Randomized Complete Block Design (RCBD) with two factors was used in this research. First factor was the sugar concentration which consists of three levels 2.5%, 5%, 7.5%. Second factor was the fermentation time which consists of five levels 8 hours, 10 hours, 12 hours, 14 hours and 16 hours. The parameters observed in this research were sugar level, total lactic acid, pH, total lactic acid bacteria (LAB), and sensory acceptances such as colour, flavor, taste and overall acceptance. The result of this research showed that the sugar concentration had significant effect to the total sugar but had no significant effect to the total lactic acid and pH. The fermentation time had significant effect to the pH, total lactic acid and total sugar. The interaction of sugar concentration and fermentation time had no significant effect to the characteristic of pH, total lactic acid, total sugar, color, flavor, taste and overall acceptance. Mung bean probiotic drink with the best characteristic was obtained at 5% of sugar concentration and 8 hours fermentation time with criteria sugar concentration levels at 8.06 %, total lactic acid 0.27 %, pH at 5.29, and 1.6 x 108 CFU/ml total LAB with sensory results state that the colour was slightly liked, the flavor was slightly liked, the taste was preferred and slightly sweet, and overall acceptance was preferred.



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