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Nectar guide [ Botany ]

Dictionary of botanic terminology - index of names

     
  Nectar guides are colour pattern or lines on the flower petals especially found in bee-pollinated plants.  
     
The nectar guides radiate out from the source of the nectar reward, and forming  a high-contrast zone with a low ultraviolet reflectance near the centre of each petal, they essentially guide the pollinators to the centre of the flower like paint on an airport runway.

This patterns are usually invisible to humans because our visual spectrum does not extend into the ultraviolet.   Bees, however, can detect ultraviolet light.   The contrasting nectar guide helps a bee quickly locate the flower's centre towards the nectar, this adaptation benefits both the flower (more efficient pollination) and the bee (rapid collection of nectar).
     

 


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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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