Boysen-jemsen (1913) conducted a study with the Avena coleoptile (sprouts from the seeds of grasses) states "displacement effect is the removal of a natural substance produced in the Avena coleoptile. Paal (1919) reinforces the opinion by stating that "the end of the rod is a growth center.
Kogl, conducted the study by removing the tip of the coleoptile and in fact the bottom showed a real growth to stop. But if the tip of the coleoptile is cut and placed in a block of agar (growth medium) for several hours and was discharged later the coleoptile tip of the block to the diletaklan the end of the rod / coleoptile is cut will cause pertumbuahn running again. This shows that there is a substance produced at the end and move down that affect growth. These substances by Kogl called auxin from the Latin meaning is Auxein grow.
gibberellin was first discovered by a Japanese pathologist, Kurosawa, when researching a disease called rice tanaamn bakane. The disease is caused by the fungus Gibberella fujikuroi, which is also known as Fusarium moniliforme. From the research results obtained that the fungus was issued a substantia / substance that is now known as gibberellins. gibberellin, the first time this substance is taken from the fungus Gibberella fujikuroi (Fusarium moniliforme, disease-causing organisms "foolish seedling" in rice). rice plants were attacked appear higher than others. These symptoms were caused by a substance released by the fungus. 1938, Yabuta and Sumuki managed to get Gibberrellin of these fungi.
Skoog (1955) conducted a study by separating the pith tissue of Nicotiana tabaccum elements cortex vessels and then placed in a growth medium suatau and the result is not the case of cell division in pith tissues. But if the network is such that the vessel is placed in contact with the pith tissue, the pith tissue of cell division will perform again. Through further research Skoog named substances that can stimulate cell division process are given feed size