There are five major classes of plant hormones (a.k.a. Plant growth regulators (Pgr's)) with perhaps a few others as candidates to take that place in the future. The five major hormone classes are Auxins[?], Cytokinins[?](CK’s), Ethylene, Gibberellins[?] (GA’s), and Abscisic Acid (ABA). Recently it has been suggested that Brassinosteroids[?] (BA’s), Jasmonates[?] (JA’s), Salicylates[?] (SA’s), and Polyamines[?] are new classes of major hormones.
... a being non-zero. These solutions are also called the roots of the equation. The formula reads
<math>
x=\frac{-b \pm \sqrt {b^2-4ac}}{2a}
</math>
The ...