Question

The elongation of the dwarf is brought about by the application of …….
(a)Cytokinins
(b)Gibberellins
(c)X-rays
(d)Vitamin C

Answer 1

Hint They are the plant growth regulators involved in regulating the expansion and influencing different developmental processes which include stem elongation, germination, flowering, enzyme induction, etc.

Complete answer:
The elongation of the dwarf is caused by the application of gibberellins. Gibberellins are growth-promoting phytohormones, which promote stem elongation in many plants. When gibberellin is applied to a plant, particularly certain dwarf varieties, this elongation could also be spectacular. Some corn and pea plants that are dwarfs as a result of one or more mutations grow to a traditional height when treated with gibberellin. Short-stemmed, high-productivity sorts of wheat have short stems as they need a decreased response to gibberellin. These varieties keep a few of their resources into stem height and high resources into grain manufacturers. Gibberellins also occur in bolting, the fast elongation of a floral stalk that happens naturally in many plants once they start flowering. Gibberellins cause stem elongation by stimulating cells to divide also on the elongate. The particular mechanism of cell elongation differs from that caused by auxin, however.

Additional information:
The exact mechanism of cell elongation varies from that caused by auxin, but. Auxins like indole ethanoic acid (IAA) induced cell elongation involve the acidification of the cell wall. In gibberellin-induced cell elongation, cell wall acidification doesn't take place, biologists don't yet skill gibberellins altered cell wall character to cause cell elongation.

So, the correct answer is ‘Gibberellins’.

Note: Gibberellin is a diterpenoid. It forms the idea of molecules like vitamins A and E. It's used on cucumber plants to supply all-male flowers. This helps the farmers to get pollen of desired characteristics to be used for hybridization. Biennial plants produce flowers only during low temperatures. When gibberellin is applied, these plants will flower regardless of the low temperatures. The dwarf sorts of plants which are genetic mutants are often made to grow by applying gibberellins to them.