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Hybrid vigour [ Genetics ]
Synonym: Heterosis

Dictionary of botanic terminology - index of names

     
  Definition  
     
   
 

Heterosis, or “hybrid vigour,” is defined as the superior performance of an offspring over the average of the parent breeds. Heterosis is greatest when crossing two parent plants of totally unrelated ancestry. Hybrid vigour can be exhibited through a variety of traits such as increased survivability and growth of crossbred or higher reproduction rates . 
 
 

 


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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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