scholarly journals Influence of microclimatic conditions on nectar exudation in Glechoma hirsuta  W. K

2005 ◽  
Vol 57 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Marina Macukanovic-Jocic ◽  
Lola Djurdjevic
Keyword(s):  
Secretion Rate ◽  
Sugar Concentration ◽  
Test Plot ◽  
Habitat Conditions ◽  
Nectar Secretion ◽  
Atmospheric Humidity ◽  
Nectar Production ◽  
Nectar Volume ◽  
Close Relationship ◽  
Microclimatic Conditions

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.

scholarly journals Comparative study of wood betony (Stachys officinalis L) melliferousness in different habitat conditions

2005 ◽  
Vol 59 (3-4) ◽  
pp. 475-484
Author(s):  
Marina Macukanovic-Jocic
Keyword(s):  
Sugar Concentration ◽  
Habitat Conditions ◽  
Air Humidity ◽  
Nectar Secretion ◽  
Nectar Production ◽  
Relative Air Humidity ◽  
Close Relationship ◽  
Nectar Sugar ◽  
Lower Temperature ◽  
Forest Conditions

Nectar production in wood betony (Stachys officinalis L), grown under differ-microclimatic habitat conditions (forest and experimental field), was analyzed. Study of tar production included determining of the total daily nectar amount (in 24 hours) per flower, the diurnal dynamics of nectar secretion (nectar amount secreted per flower at two hour intervals during the day), and nectar sugar concentration. The aim of this study was to evaluate the influence of microclimatic parameters humidity, air temperature and evaporation) on the secretion process and nectar sugar concentration. Comparative analyses of nectar secretion in Stachys officinalis, grown in two environmentally different habitats, confirmed that this process varied as a function of micro-climatic habitat conditions, and did not reveal a close relationship between these conditions and sugar concentration in nectar. A diurnal model of nectar secretion with two secretion peaks was found. A higher amount of nectar per flower, with an increasing tendency during the first half of the day, and a decreasing tendency during the afternoon was measured in forest conditions (lower temperature, higher relative air humidity and lower evaporation).

scholarly journals Flower mites decrease nectar availability in the rain-forest bromeliad Neoregelia johannis

2010 ◽  
Vol 26 (4) ◽  
pp. 373-379 ◽  
Author(s):  
Tadeu J. Guerra ◽  
Gustavo Q. Romero ◽  
Woodruff W. Benson
Keyword(s):  
Rain Forest ◽  
Sugar Content ◽  
Sugar Concentration ◽  
Production Rates ◽  
Nectar Production ◽  
Nectar Volume ◽  
Bombus Morio ◽  
Nectar Rewards ◽  
Flower Mites ◽  
Nectar Availability

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.

scholarly journals Variation in Nectar Volume and Sugar Concentration ofAllium ursinumL. ssp.ucrainicumin Three Habitats

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ágnes Farkas ◽  
Réka Molnár ◽  
Tamás Morschhauser ◽  
István Hahn
Keyword(s):  
Soil Properties ◽  
Brown Forest Soil ◽  
Full Bloom ◽  
Floral Nectar ◽  
Nectar Production ◽  
Nectar Volume ◽  
Sessile Oak ◽  
Microclimatic Conditions ◽  
The Difference

Floral nectar volume and concentration of ramson (Allium ursinumL. ssp.ucrainicum) were investigated in three different habitats, including two types of sessile oak-hornbeam association on brown forest soil with clay illuviation and a silver lime-flowering ash rock forest association on rendzina. Daily nectar production ranged from 0.1 to 3.8 μL per flower with sugar concentrations of 25 to 50%. Mean nectar volumes and concentrations showed significant differences between freely exposed flowers and covered flowers, which had been isolated from flower visitors 24 h prior to nectar studies. Both the amount and quality of nectar were affected by microclimatic conditions and soil properties and varied between populations at different habitats. In the silver lime-flowering ash rock-forest association mean nectar volumes and concentrations were lower than in a typical sessile oak-hornbeam association on three occasions, the difference being significant in two cases. During full bloom, the date of sampling did not have a profound effect on either nectar volume or concentration.

Rewards 2: The Biology of Nectar

2011 ◽  
Author(s):  
Pat Willmer
Keyword(s):  
Chemical Composition ◽  
Nectar Secretion ◽  
Water Reward ◽  
Floral Nectar ◽  
Nectar Production ◽  
Nectar Volume ◽  
Floral Reward ◽  
Nectar Concentration

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.

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 Nectary structure and nectar secretion of Echium russicum J. F. Gmel. flowers

2012 ◽  
Vol 60 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Mirosława Chwil ◽  
Elżbieta Weryszko-Chmielewska
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Sugar Concentration ◽  
Lateral Part ◽  
Flowering Period ◽  
Nectar Secretion ◽  
Nectar Production ◽  
Anomocytic Stomata ◽  
Scanning Electron

In this study, the micromorphology of nectaries in <i>Echium russicum</i> J. F. Gmel. flowers was determined by using scanning electron microscopy (SEM) and their anatomy by using light microscopy (LM). The rate of nectar production of flowers and sugar concentration in nectar were investigated. The nectary gland is located below the ovary of the pistil. It is composed of 4 parts corresponding to the parts of the ovary. The widest regions of the nectar-producing tissue are situated by the furrows separating the adjacent parts of the ovary. Nectar is secreted through anomocytic stomata, located only in the lower part of the nectary. The stomata were distributed evenly or they formed clusters of 2-3. The average number of stomata on the surface of the whole nectary was 184. At the nectar secretion stage, open and closed, as well as not fully mature stomata were observed. The orientation of most of the stomata was parallel to the nectary base. The cuticle surface of the cells of the upper and lateral part of the nectary was smooth, whereas in the region producing stomata it showed various folds facilitating the retention of nectar. The flowers produced nectar throughout the flowering period. The weight of nectar secreted throughout the lifetime of ten flowers was, on the average, 20 mg, with the concentration of sugars of 58% and their weight reaching 17 mg.

scholarly journals Canopy Position, Defoliation, and Girdling Influence Apple Nectar Production

HortScience ◽  
1991 ◽  
Vol 26 (5) ◽  
pp. 531-532 ◽  
Author(s):  
Richard J. Campbell ◽  
Richard D. Fell ◽  
Richard P. Marini
Keyword(s):  
Sugar Concentration ◽  
Nectar Production ◽  
Nectar Volume ◽  
Canopy Position ◽  
Nectar Sugar

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.

scholarly journals Patterns of Nectar Production in Asclepias curassavica (Apocynaceae))

2019 ◽  
Vol 25 ◽  
Author(s):  
Steven Broyles
Keyword(s):  
Pollen Germination ◽  
New World ◽  
Volume Concentration ◽  
Sugar Concentration ◽  
Nectar Production ◽  
Nectar Volume ◽  
Asclepias Curassavica ◽  
Daily Rate ◽  
Insect Visitation

Milkweeds are important nectar resources for insects in the New World. In addition, nectar is the germination medium for milkweed pollen. This study is the first controlled, greenhouse examination of patterns of nectar production in a milkweed species. We measured nectar volume, concentration, and mg of sugar in the pantropical, weedy milkweed Asclepias curassavica. Our results show that A. curassavica secretes nectar primarily during daylight hours and it continues at a constant daily rate for four to five days. Freshly secreted nectar is lower in sugar concentration than older nectar. This provides an opportunity for milkweed pollen to germinate throughout the day, but pollen germination could be inhibited at times when the sugar concentration increases. Nectar production in A. curassavica is adapted to attract diurnal insect pollinators over several days and to allow pollen germination to occur quickly. Significant differences in nectar production exist among plants and among inflorescences within plants. Nectar production increases in flowers when nectar is extracted using paper wicks that simulate removal by insects in nature. Removal-enhanced nectar production in milkweeds may allow plants to adjust resources to inflorescences receiving insect visitation. Significant inter-plant differences in nectar production and the unique milkweed flower provides a model system for examining the role of pollinator-mediated selection on nectar traits.

Nectar secretion pattern and removal effects in three species of Solanaceae

1993 ◽  
Vol 71 (10) ◽  
pp. 1394-1398 ◽  
Author(s):  
Leonardo Galetto ◽  
Luis Bernardello
Keyword(s):  
Sugar Production ◽  
Nectar Secretion ◽  
Nicotiana Glauca ◽  
Time Intervals ◽  
Nectar Production ◽  
Nectar Volume ◽  
Significant Difference ◽  
Flower Age ◽  
Nicotiana Longiflora ◽  
Nectar Sugar

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.

scholarly journals Nectar production of pear (Pyrus communis L.) cultivars

2000 ◽  
Vol 6 (3) ◽  
Author(s):  
P. Benedek ◽  
G. Kocsisné Molnár ◽  
J. Nyéki
Keyword(s):  
World Literature ◽  
Fruit Trees ◽  
Significant Negative Correlation ◽  
Sugar Concentration ◽  
Cold Weather ◽  
Nectar Production ◽  
Pyrus Communis L ◽  
The World ◽  
Pear Trees ◽  
Very High

Detailed studies were made on the nectar production of 44, 16 and 18 pear cultivars, respectively, in a cultivar collection of pear during three consecutive years with highly different weather in the blooming. Results clearly show that pear does not necessarily produce small amount of nectar as stated in the world literature. In fact, pear can produce extremely high amount of nectar sometimes much higher than other temperate zone fruit trees species but its nectar production is highly subjected to weather, first of all to air temperature. Low nectar production seems to be more frequent than high one and cold weather can prevent its nectar production at all. On the other hand, results corroborate to the earlier statements on the low sugar concentration of pear nectar. There is a highly significant negative correlation between the amount of nectar produced by pear flowers and its sugar concentration (r = -0.52, n = 291, p< 0.001 for 1996, r = -0.34, n = 197, p< 0.001 for 1998). Sugar concentration in individual flowers may be up, to 40% in exceptional cases but generally it is well below 20%. Very high figures for sugar concentration in pear nectar at the literature seem to be incomprehensible. In contrast of some earlier statement in the literature no real difference could be established in the nectar production of pear cultivars, based on much more measurements than in earlier studies. Very low sugar concentration in pear nectar can explain the fact that the overwhelming majority of honeybees are pollen gatherers at pear trees even in the case of exceptionally high nectar production.  

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