Question

The hormone which promotes flowering in long day conditions and controls sex expression is
A. Auxin
B. Cytokinins
C. Gibberellins
D. Ethylene

Answer 1

Like hormones like insulin, glucagon, adrenaline, etc. in humans, plants also have hormones that are responsible for the growth and maturation of the plant. Plant hormones are also called ‘Phytohormones’.

Complete answer: Gibberellins are found in higher plants and are acidic in nature. It allows the elongation of stem and internodes. It is also responsible for the sex expression of plants e.g. it promotes maleness in cannabis. They also induce flowering and delay senescence.
-Auxin meaning ‘to grow’ is the phytohormone responsible for the growth of the roots and promotes apical dominance. It is present in all parts of the plant and is transported. Indole-3-acetic acid and Indole butyric acid are natural auxins present in plants. 2,4-D and NAA are artificially produced.
-Cytokinins are named from the name cytokinesis and are responsible for cell division and growth of shoot and stem. It also allows the formation of the chloroplast. Natural cytokinins present in plants are Zeatin and isopentenyl adenine. It also delays the senescence of leaves and overcomes apical dominance. The artificially produced cytokinins are kinetin, diphenylurea, thidiazuron.
-Ethylene is present in gaseous form and is both a plant growth hormone and an inhibitor. It promotes the ripening of fruits faster, promotes senescence, and induces root hair growth. It also allows the elongation of internodes and petioles.
Hence, the correct answer is an option (C).

Note: Plant hormones are derivatives of indole, terpenes, adenine, carotenoids, and gases. Plant hormones can act synergistically or individually. They are produced in all the parts of the plant and are transported.