Nectar

Source: Wikipedia, the free encyclopedia.
For other uses, see Nectar (disambiguation).

Nectar of camellia
Orange-yellow nectaries and greenish nectar in buckwheat flowers
An Australian painted lady feeding on a flower's nectar
Gymnadenia conopsea flowers with nectar-filled spur

Nectar is a

A. m. scutellata and the western honey bee.[citation needed
]

Nectar is an economically important substance as it is the sugar source for honey. It is also useful in agriculture and horticulture because the adult stages of some predatory insects feed on nectar. For example, a number of predacious or parasitoid wasps (e.g., the social wasp species Apoica flavissima) rely on nectar as a primary food source. In turn, these wasps then hunt agricultural pest insects as food for their young. [1]

Nectar is most often associated with flowering plants

angiosperms, but it is also produced by other groups, including ferns.[2]

Etymology

Nectar is derived from

AD 1600.[3]

Floral nectaries

A nectary or nectarine is floral tissue found in different locations in the flower and is one of several secretory floral structures, including elaiophores and osmophores, producing nectar, oil and scent respectively. The function of these structures is to attract potential pollinators, which may include insects, including bees and moths, and vertebrates such as hummingbirds and bats. Nectaries can occur on any floral part, but they may also represent a modified part or a novel structure.[4] The different types of floral nectaries include:[5]

  • receptacle (receptacular: extrastaminal, intrastaminal, interstaminal)
  • hypanthium (hypanthial)
  • tepals
    (perigonal, tepal)
  • sepals
    (sepal)
  • petal (petal, corolla)
  • stamen (staminal, androecial: filament, anther, staminodal)
  • pistil
    (gynoecial: stigmatic, stylar)
    • pistillodes (pistillodal, carpellodial)
    • ovaries (ovarian: non-septal, septal, gynopleural)

Most members of

vascular strand in the nectary to assist in transport over a longer distance.[9][4]

Pollinators feed on the nectar and depending on the location of the nectary the pollinator assists in

pistil, of the plant and pick up or deposit pollen.[10] Nectar from floral nectaries is sometimes used as a reward to insects, such as ants, that protect the plant from predators. Many floral families have evolved a nectar spur. These spurs are projections of various lengths formed from different tissues, such as the petals or sepals. They allow for pollinators to land on the elongated tissue and more easily reach the nectaries and obtain the nectar reward.[6] Different characteristics of the spur, such as its length or position in the flower, may determine the type of pollinator that visits the flower.[11]

Defense from

sugars found in nectar, certain proteins may also be found in nectar secreted by floral nectaries. In tobacco plants, these proteins have antimicrobial and antifungal properties and can be secreted to defend the gynoecium from certain pathogens.[12]

Floral nectaries have

flies, moths, butterflies, and birds, nectaries in the ovaries are common because they are able to reach the nectar reward when pollinating. Sepal and petal nectaries are often more common in species that are pollinated by short-tongued insects that cannot reach so far into the flower.[15]

Secretion

Nectar secretion increases as the flower is visited by pollinators. After pollination, the nectar is frequently reabsorbed into the plant.[16] The amount of nectar in flowers at any given time is variable due to many factors, including flower age,[17] plant location,[18] and habitat management.[19]

Extrafloral nectaries

See also:
Plant defenses against herbivory
Extrafloral nectaries with droplets of nectar on the petiole of a wild cherry (Prunus avium) leaf
Extrafloral nectaries on a red stinkwood (Prunus africana) leaf

Extrafloral nectaries (also known as extranuptial nectaries) are specialised nectar-secreting plant glands that develop outside of flowers and are not involved in

domatia), pits or raised regions (e.g., Euphorbiaceae). The leaves of some tropical eudicots (e.g., Fabaceae) and magnoliids (e.g., Piperaceae) possess pearl glands or bodies which are globular trichomes specialised to attract ants. They secrete matter that is particularly rich in carbohydrates, proteins and lipids.[20][22]

Drynaria quercifolia frond

While their function is not always clear, and may be related to regulation of sugars, in most cases they appear to facilitate plant insect relationships.

prey.[25]

Loxura atymnus butterflies and yellow crazy ants consuming nectar secreted from the extrafloral nectaries of a Spathoglottis plicata bud

botanist Federico Delpino in his important monograph Funzione mirmecofila nel regno vegetale (1886). Delpino's study was inspired by a disagreement with Darwin, with whom he corresponded regularly.[26]

Extrafloral nectaries have been reported in over 3941 species of

Salix (Salicaceae), Prunus (Rosaceae) and Gossypium (Malvaceae).[24]

Nylanderia flavipes ant visiting extrafloral nectaries of Senna

Foliar nectaries have also been observed in 101 species of

Phylogenetic studies and the wide distribution of extrafloral nectaries among vascular plants point to multiple independent evolutionary origins of extrafloral nectaries in at least 457 independent lineages.[22]

Components

The main ingredients in nectar are sugars in varying proportions of sucrose, glucose, and fructose.[28] In addition, nectars have diverse other phytochemicals serving to both attract pollinators and discourage predators.[29][7] Carbohydrates, amino acids, and volatiles function to attract some species, whereas alkaloids and polyphenols appear to provide a protective function.[29] The Nicotiana attenuata, a tobacco plant native to the US state of

California buckeye.[31] Nectar contains water, essential oils, carbohydrates, amino acids, ions, and numerous other compounds.[16][7][32]

Similar attractive substances

Some insect pollinated plants lack nectaries, but attract pollinators through other secretory structures. Elaiophores are similar to nectaries but are oil secreting. Osmophores are modified structural structures that produce volatile scents. In

corona.[4]

See also

References

  1. ^ "Killer Bees". www.columbia.edu. Retrieved 17 January 2022.
  2. PMID 23609022
    .
  3. ^ a b "Nectar". Online Etymology Dictionary, Douglas Harper. 2018. Retrieved 28 May 2018.
  4. ^ a b c d Rudall 2007, pp. 96–98.
  5. ^ Nicolson et al 2017, p. 41.
  6. ^ a b Willmer, Pat. Pollination and floral ecology. Princeton University Press, 2011.[page needed][ISBN missing]
  7. ^ a b c d Nicolson et al 2017.
  8. S2CID 85332036
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  9. doi:10.1002/j.1537-2197.1977.tb15719.x
    .
  10. S2CID 11206264
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  11. S2CID 29016446
    .
  12. S2CID 19339791
    .
  13. JSTOR 2399498. INIST 6608807
    .
  14. S2CID 20457047
    .
  15. JSTOR 3298546
    .
  16. ^ a b Thornburg 2001.
  17. ISSN 0044-8435
    .
  18. S2CID 41950102
    .
  19. S2CID 248300845
    .
  20. ^ a b c d Rudall 2007, pp. 66–68.
  21. ^
    doi:10.1046/j.1365-2435.2000.00480.x
    .
  22. ^
    PMID 23087129
    .
  23. ^ Plant-Provided Food for Carnivorous Insects – Cambridge University Press
  24. ^ a b Sezen, Uzay. "Ants defending extrafloral nectaries of the passion flower (Passiflora incarnata)". Retrieved 6 January 2012.
  25. ^ Merbach, M. 2001. Nectaries in Nepenthes. In: C.M. Clarke Nepenthes of Sumatra and Peninsular Malaysia. Natural History Publications (Borneo), Kota Kinabalu.[page needed]
  26. ^
    PMID 21490417
    .
  27. ^ Nectaries in ferns: their taxonomic distribution, structure, function, and sugar composition
  28. PMID 16373370
    .
  29. ^
    PMID 19847105
    .
  30. ^ Everts, Sarah (1 September 2008). "Two-Faced Flowers". Chemical & Engineering News.
  31. ^ C.Michael Hogan (2008) Aesculus californica, Globaltwitcher.com, ed. N. Stromberg
  32. ^ Park & Thornburg 2009.

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