Nectar secretion pattern and removal effects in three species of Solanaceae

1993 ◽  
Vol 71 (10) ◽  
pp. 1394-1398 ◽  
Author(s):  
Leonardo Galetto ◽  
Luis Bernardello

Nectar secretion pattern and effects of nectar removal were compared in three Argentinean Solanaceae: Nicotiana glauca, which is hummingbird pollinated, and Nicotiana longiflora and Petunia axillaris, which are sphinx moth pollinated. Nectar volume, concentration, and sugar production were measured at different time intervals according to the species' flower life span. Nectar volume and total sugar production increased as a function of flower age in both species of Nicotiana analyzed; however, these parameters were quite stable in P. axillaris. This species produced less nectar and nectar sugar than the other two. When all sets with nectar removal were compared with the controls, significant differences were found in nectar volume and quantity of nectar sugar in N. longiflora, and in sugar concentration in P. axillaris. In the latter, the observed difference did not affect the total amount of sugar secreted. Nicotiana glauca did not show any significant difference in the parameters analyzed. Total nectar production was inhibited by periodic removal in N. longiflora, while in N. glauca and P. axillaris it was unaffected. Key words: nectar secretion pattern, nectar removal, Nicotiana, Petunia, Solanaceae.

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.


2020 ◽  
Vol 153 (1) ◽  
pp. 59-66
Author(s):  
Thomas Mione ◽  
Isaac Argeo Diaz

Background and aims – Flowers of Jaltomata quipuscoae (Solanaceae) secrete blood-red nectar that serves as an energy reward and possible attractant to pollinators. The purposes of this study were to determine whether simulated pollinator visits (manual removal of nectar) stimulates replenishment of nectar, and report the pattern of nectar presentation during the lifespan of the flower. Methods – For the nectar replenishment experiments flowers were paired: each pair of flowers was selected to be on the same plant and at the same developmental stage. From all 62 flowers nectar was removed and discarded (not measured) at time zero. Then, over a period of eight hours, the nectar of one flower was measured four times, i.e., every two hours, while nectar of the paired control flower was measured only at the end of the eight-hour period. In the nectar dynamics experiment five sets of flowers received different treatments: flowers were unmanipulated for zero, one, two, three or four days and then nectar was removed once every day. The volume of nectar produced and concentration of sugar in the nectar were recorded at each extraction for both studies.Key results – In the nectar replenishment study significantly higher nectar volume and consequently significantly higher total sugar content was present in the experimental nectar-extracted flowers. In the nectar dynamics study, nectar was produced starting on day one or two, continuously through the life of the open flowers until one or two days before the corolla senesced. Delay of nectar removal from different flower sets for zero, one, two, three or four days resulted in a linear increase in nectar volume and total nectar sugar production, and had little or no effect on the cumulative (life of the flower) nectar production. Floral longevity, seven to ten days, was not affected by a single removal of nectar each day.Conclusions – The floral nectary of J. quipuscoae responded to nectar removal by secreting more nectar, and thus more total sugar (not a higher concentration of sugar) than was secreted by control flowers. In flowers from which nectar was not removed, nectar volume and thus total sugar secreted continued to accumulate linearly, suggesting that reabsorption of nectar either does not occur or is slow relative to the rate of secretion. The more we (or pollinators) take, the more the flowers make: the volume of nectar and sugar production increase if nectar is removed frequently but not if nectar is removed infrequently.


Author(s):  
Pat Willmer

This chapter examines the biology of nectar, the main secondary floral reward in an evolutionary sense. As a commodity, nectar is easy for plants to produce and easy for animals to handle; its sugars are simple to metabolize and thus to use as a readily available fuel for an animal’s activities. Nectar is a crucial factor in determining the interactions of flowers and their visitors. The chapter first provides an overview of how floral nectar is produced in a nectary before discussing nectar secretion, the chemical composition of nectar, and nectar volume. It then considers nectar concentration and viscosity, nectar as a sugar and energy reward, and nectar as a water reward. It also explores daily, seasonal, and phylogenetic patterns of nectar production, how flowers control their nectar and their pollinators, and problems in measuring and quantifying nectar. The chapter concludes with an analysis of the costs of nectar gathering.


2005 ◽  
Vol 57 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Marina Macukanovic-Jocic ◽  
Lola Djurdjevic

The nectar production of Glechoma hirsuta W. K. grown under different microclimatic habitat conditions was evaluated by determining the total daily nectar quantity per flower, diurnal dynamics of nectar secretion, the nectar secretion rate, and sugar concentration. Comparative analyses of nectar production in Glechoma hirsuta grown in a forest and on a test plot confirmed that this process varied as a function of microclimatic parameters (atmospheric humidity and air temperature), but did not reveal a close relationship between these parameters and sugar concentration in nectar. More intensive nectar secretion, with a decreasing tendency during the day, and higher total daily nectar volume per plant (1.603 ml/flower) were measured in the forest habitat. Diurnal variation in nectar production with two secretion peaks was found at both localities, and the secretion patterns were rather similar. Regarding the nectar secretion rate, G. hirsuta is a slow producer secreting less than 0.07 ml/h.


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.


2020 ◽  
Vol 35 (3) ◽  
pp. 176-183
Author(s):  
Salma Y. Essa ◽  
Ali A. Bataw

The study aimed to investigate the effects of nectar secretion and climate conditions on the number of honeybee workers foraging on flowers of three different plant species. Nectar samples were taken at different hours of the day. Handling and traveling time of each bee per flower were recorded. The results showed a significant difference during daylight hours on nectar volume (P>0.05). The highest amount of nectar was recorded at 10 am on a Prunus domestica flower plant (0.5± 0.2) and the lowest on a Pyrus communis flower plant at 8:00 am with (0.0132 ± 0.008). Also, the highest recorded handling time was on a Malus domestica flower plant at 10 am with (6.1± 1.7 Sec). And while there was an absence of mean handling time at 4:00 pm on the P. communis flower plant, The results showed that the highest traveling time recorded was on a M. domestica flower plant at 12 am with (2.2 ± 0.1 Sec) compared with the P. communis flower plant that recorded the lowest traveling time at 4:00 pm with (0.1± 0.1 Sec). Furthermore, the results revealed that the preference of Apis mellifera was the M. domestica flower plant. The findings showed a significance (P>0.05) between the effects of climate conditions on the number of bees during visits, while also revealing that there was a relationship between high temperatures and an increase in the number of visiting bees. Meanwhile, the number of visits decreased during the hours of observation with lower humidity.


2012 ◽  
Vol 61 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Marta Dmitruk

The study was conducted on experimental plots in the conditions of Lublin. In the years 1998-2000 flowering, nectar secretion and insect visitation of male and female flowers of two winter squash (<i>Cucurbita maxima</i> Duch.) cultivars: 'Ambar' and 'Amazonka', were studied. The plants flowered from July to October. The flower life span was within the range of 7-10 hours. Female flowers of cv. Ambar were marked by the most abundant nectar secretion (129 mg). The nectar sugar content can be estimated as average (25%-35%). Winter squash nectar contained 84% of sucrose as well as 8-9% of fructose and 7%-8% of glucose. Flowers of the studied taxa were frequently foraged by the honey bee (66%-98% of total insects) and bumblebees (1%-30%).


1981 ◽  
Vol 59 (2) ◽  
pp. 156-160 ◽  
Author(s):  
R. C. Plowright

Nectar secretion in unpollinated flowers of Clintonia borealis (Ait) Raf. (Liliaceae) began as the tepals first opened, reached a maximum at about the time the anthers dehisced, and ceased after the tepals began to curl back. Total lifetime sugar production was highly correlated with flower size and was not affected by daily nectar removals. Nectar concentration varied widely as a response to fluctuations in atmospheric relative humidity. It is suggested that since freshly secreted Clintonia nectar ranged in concentration from 4 to 63% sugar by weight, comparisons of nectar concentration among different species may not be meaningful unless accompanied by environmental data at and prior to the time of sampling.


1963 ◽  
Vol 41 (12) ◽  
pp. 1675-1679 ◽  
Author(s):  
G. W. Wood ◽  
F. A. Wood

The relationship between nectar production and fruitset of blueberry is not significantly strong. Measurements of nectar volume and weight of nectar sugar were not correlated with fruitset, while nectar concentration showed a significant relationship [Formula: see text] in only 1 year out of 3. Constituent nectar sugars were not involved in the relative attractiveness to pollinators of the various blueberry clones studied or between blueberry and other plants in bloom at the same time. Pollinator attraction is inversely related to age of bloom.


1961 ◽  
Vol 39 (5) ◽  
pp. 1037-1040 ◽  
Author(s):  
G. W. Wood

Nectar samples were harvested daily from exposed and caged portions of the low-bush blueberry, Vaccinium angustifolium (varieties laevifolium House and nigrum (Wood) Dole). Pollination activity on the exposed bloom had no significant effect on mean nectar volume and concentration but caused a slight reduction in the mean weight of nectar sugar. Nectar volume and weight of nectar sugar increased directly with the age of inflorescence in all clones.


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