Dormancy

Dormancy [ Physiology - Botany ]	Dictionary of botanic terminology - index of names
Also: Rest, Resting stage, Growth cessation or Arrestment Adjective: Dormant


	*Dormancy is a* *general term denoting the non-growing (resting, quiescent or inactive) phase of plants life or of viable seeds.*

Dormancy is a state of low metabolic activity that occurs during the yearly cycle in plants or seeds when no outwardly visible growth takes place.
It is a physical or physiological condition that suspends or prevents growth or germination even in the presence of otherwise favourable conditions.

It is possible to identify two principal types of dormancy:

Endodormancy: a period of quiescence caused by conditions or factor within the plant or organ itself. (For example the winter rest )
Ectodormancy: ( also Ecodormancy or diapause) (exogenous or external dormancy ) a period of quiescence caused directly by adverse conditions, and lasting only while they prevail.

Dormancy affected by :

Photo-period
Environmental induction
Low temperature and effective chilling temperatures in colder regions
Hot and drought in warmer areas
Phytohormones
Site of the bud and bud differences
Environment and/or cultural practices
Dormancy breaking chemicals

Plant dormancy in temperate zones (the Winter rest) usually takes place during colder periods when plant leaves have fallen or the top growth has died down and seeds, buds bulbs or tubers exhibit a lack of growth or flowering it is a survival strategy which temperate climate species are generally believed to have to survive winters unfavourable conditions.
The plant in tropical areas goes dormant especially during extended hot, dry periods (see dry season)

Seed dormancy is the state of inhibited germination of seeds that suspends or prevents germination even in the presence of otherwise favourable germination conditions. The breaking of seed dormancy requires moisture, sometimes cold temperatures and/or abrasion of the seed coat. ( see: scarification)

During dormancy many plants require less water, cooler temperatures and fertilizing should be withheld ( see: overwintering). Dormancy is thus a good time to transplant or prune some species of plants ( e.g. Trees).

See: Winter rest

Advertising

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