Growing season

Growing season [ Botany - Ecology ]	Dictionary of botanic terminology - index of names
Synonym: Vegetative season, Frost-free season.


	*That part of the year when temperatures and moisture are favourable for vegetation growth.*

The growing season is the period during which plant growth takes place, and is usually measured in days. Growing seasons vary depending on local climate. Geographical location, (latitude and altitude), temperature, daylight hours (photoperiod), and rainfall, may all be critical environmental factors. It can also vary by crop, as different plants have different freezing thresholds. In temperate climates the growing season for indigenous vegetation and cultivated crops (also called Frost-free Season) is limited by seasonal changes in temperature and is defined as the period from the average date of the last killing frost of spring and the first killing frost of autumn, at which time annual plants die and biennials and perennials cease active growth and become dormant for the cold winter months. In equatorial and tropical regions, in which there is less seasonal temperature change, the growing season ordinarily lasts all year and the amount of available moisture often determines the periods of plant growth; in the rainy season growth is luxuriant and in the dry season many plants become dormant. In desert areas, growth is almost wholly dependent on moisture. In the Arctic the growing season is short but concentrated; the number of daylight hours is so large that the total amount of sunlight equals that of a temperate growing season with shorter days, Combinations of factors affect the growing season; For examples in Mediterranean type of climate (with winter rainfall and dry summers) plant growth occurs during the winter and dormancy during the summer.

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