Nectary

Nectary [ Botany ]
Synonym: Nectar gland

Dictionary of botanic terminology
index of names


	A multicellular glandular structure secreting nectar. Found in flowers and on vegetative parts in some species of plants, often forming projections, lobes, or disk-like structures.

Nectaries are organs usually located within the base of the flower (floral nectaries) or on other portions of the plant (extrafloral nectaries)

Extrafloral Nectary also called (in cactus) Areolar gland [ Botany ]

Red nectary of
Coryphantha echinoidea

Extra-floral nectaries (areolar glands) are glands, usually located (in Cactus) in the tubercle-grooves or in the axils.

These nectary-glands exude a viscous juice ( nectar) with a high sugar-content and represent a sophisticated strategy for ant attraction.

A drop of nectar
(Glandulicactus wrightii)

The first hypothesis for why plants secrete extra floral nectar is that the presence of pugnacious ants seems to reduce the vulnerability of flower buds by herbivores insect, resulting in greater fruit production and tissue survival. (or by decreasing seed predation on plants.)
The second hypothesis is that they distract ants from foraging at floral nectaries, this might also serve as an adaptation to reduce ant visitation to flowers.
The third hypothesis is the nutrient enhancement. Ant colonies tend to concentrate nutrients in the immediate vicinity of their nests -- through storing food, discarding debris, and defecating - plant that bearing extra floral nectar attract ant nests to their base.
Moreover ants can play an important rule in distributing the seeds of these plant.
In humid conditions, the nectar exudation (if not completely removed by ants) can cause the formation of mould which leads to ugly black-colouring of the epidermis. To prevent this, spray off the plant with water to remove the nectar. And provide a very good ventilation.
(For example Coryphantha echinoidea)
Moreover ants can play an important rule in distributing the seeds of these plant.

In humid conditions, the nectar exudation (if not completely removed by ants) can cause the formation of mould which leads to ugly black-colouring of the epidermis. To prevent this, spray off the plant with water to remove the nectar. And provide a very good ventilation.
(For example Coryphantha echinoidea)

Floral Nectary [ Botany ]

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994