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(1) Honeydew   [ Phytopathology - Phytoparasitology]

Dictionary of botanic terminology
index of names

:
     
  Sticky, sugary liquid secreted and deposited on plants by juice-sucking insects such as aphid and mealybugs.  
     
A liquid mixture of sugars and other plant-derived chemicals excreted by some species of insects (especially aphids, scales, mealybugs, whiteflies and some caterpillars) that is high in sugar content. When these insects feed on plants, honeydew drips from them onto plant leaves or onto the ground.
Other insects used honeydew as food, particularly ants of many species are avid feeders on honeydew, and also some ants will actually "farm" aphids and protect them against predators and parasitoids to protect this energy source.

Honeydew is also an excellent medium for the growth of some fungi and unconsumed honeydew on plant surfaces promotes growth of a black fungus called sooty mould, which may become so dense that it interferes with metabolism of the plant.


Honeidew drops on a plant surface
 infested by woolly aphids.


Compare with: with nectar.
 
     
(2) Honeydew   [ Phytopathology ]
     
  An exudate from the surface of some galls.  
     
 
     

 


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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
     

 

 

 

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