Stem elongation is affected by- A. Gibberellin and florigen B. Auxin and Gibberellin C. Florigen and Kinin D. Kinin and auxin
Option B.Auxin and gibberellin are growth promoting phytohormones. Auxin word is derived from Greek 'auxein' meaning to grow. The term auxin is applied to the indole-3-acetic acid (IAA), and to other natural and synthetic compounds having certain growth regulating properties. They are generally produced by the growing apices of the stems and roots, from where they migrate to the regions of their action. Gibberellic acid (GA3) was one of the first gibberellins to be discovered and remains the most intensively studied form. All GAs are acidic. They produce a wide range of physiological responses in the plants. Their ability to cause an increase in length of axis is used to increase the length of grapes stalks. Gibberellins, cause fruits like apple to elongate and improve its shape.
