Describe the discovery of gibberellins.

(N/A) In the early part of the $20^{\text{th}}$ century,the 'bakane' (foolish seedling) disease of rice was reported to be caused by a fungal pathogen,$Gibberella$ $fujikuroi$.
The symptoms shown by the infected plants were abnormally elongated stems,little or no production of grains,and the plants became weak.
Later,it was identified by $E$. Kurosawa that the active substance secreted by the fungus,which caused these symptoms,was gibberellic acid.