Growth and Development of Horticultural Crops (1+1)

Nature of the Floral Hormone

• The nature of floral hormone was named as florigin, which can be translocated from leaves to the apical tips situated at other parts of the plant resulting in flowering.
  
• Grafting experiments in cocklebur plants have even proved that the floral hormone can be translocated from one plant to another.
  
• For example, if one branched cocklebur plant which has been exposed to short day conditions is grafted to another cocklebur plant kept under long day condition, flowering occurs on both the plants . Obviously the floral hormone has been transmitted to the receptor plant through graft union.
  
• But if a cocklebur plant is grafted to another similar plant both of which have been kept under long day conditions, flowering will not occur on either of the two plants.
  
• It has also been indicated that the floral hormone may be identical in short-day and long-day plants. For example, grafting experiments between certain long-day plants and short –day plants have shown that flowering occurs on both the plants even if one of them has been kept under non-inductive photoperiods.