Apical dominance is caused by

Which of the following movements is not related to changes in auxin levels?

After a series of experiments,it was concluded that the ...$A$... of coleoptile was the site of transmittable influence that caused the ...$B$... of the entire coleoptile. Complete the given statement with the correct combination of options given in the codes below.

Who among the following discovered the $Avena$ curvature test to find out the concentration of auxins?

Auxins are growth hormones capable of promoting cell elongation. They have been used in horticulture to promote growth,flowering,and rooting. Write a line to explain the meaning of the following terms related to auxins:
$(a)$ Auxin precursors
$(b)$ Antiauxins
$(c)$ Synthetic auxins

Which plant hormone prevents the premature shedding of leaves and fruits but promotes the abscission of older,mature leaves and fruits?