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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. |
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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 |
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The symptom of magnesium deficiency
occurs in the older leaves first and then is exhibited in the middle
leaves of the plant. A bronze yellow colouring (Interveinal
chlorosis) occurs in a V-shape
and the tongue of tissue along the midvein, towards the base of the
leaf, usually remains green. This is a distinctive symptom of
magnesium deficiency. In some cases these leaves may redden or
develop dead areas along the leaf margin or between the veins. 
