Who isolated auxin from tips of coleoptiles of oat seedling?

Highest concentration of auxins exists in

Which plant hormone prevents pre-mature fruit drop in apple,pear and orange?

The presence of auxins in a solution can be tested by:

After a series of experiments,it was concluded that the ....$A$.... of coleoptile was the site of transmittable influence that caused the bending of the entire coleoptile.

Formation of intrafascicular cambium is induced by