Carotenoid

Carotenoid [ Botany - Biochemistry ]
(carotene)

Dictionary of botanic terminology - index of names


	Carotenoid is a class of plant pigments occurring in red, orange, yellow and brown colours. The carotenoids are found in most higher plants and generate many of the colours typical of autumn foliage; floral colours that attract pollinators; and the characteristic colours of many fruits and vegetables.

The carotenoids are divided into two subgroups: the carotenes and the xanthophylls. Carotene is the pigment responsible for the colour of carrots. Carotene also assists photosynthesis by transmitting energy from absorbed light to chlorophyll. The oxygenated derivatives of carotenes are known as xanthophylls. (compare with: chlorophyll, betalains, anthocyanin, flavonoids)

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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