Phenotype

Phenotype [ Biology ]

Dictionary of botanic terminology - index of names


	*The observable or measurable outward characteristics of an individual organism determined by the interaction of its genetic make-up with the environment.*

The phenotype of an individual organism is either its total physical appearance and constitution, or a specific manifestation of a trait, such as size or colour, or the presence or absence of a disease, that varies between individuals and manifested throughout its life. A single characteristic can be referred to as a "trait," although a single trait is sometimes also called a phenotype. Phenotype traits are determined to some extent by the genes present in an individual. Some phenotypes (such as the colour of a flower) are completely determined by heredity, while others (such as the size of a plant) are readily altered by environmental agents. . Many phenotypes are determined by multiple genes and influenced by environmental factors.

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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