Question

Which one of the following pairs is not correctly matched?
(a)Adenine derivative - kinetin
(b)Carotenoid derivative - ABA
(c)Terpenes - IAA
(d)Indole compounds - IBA
(e)Gas - Ethylene

Answer 1

Hint: This acid is one of the derivatives of indole. It contains a carboxymethyl substituent. It is the most common naturally occurring plant hormone, while an example of this naturally occurring hydrocarbon compound is turpentine oil derived from pinus resin.

Complete answer:
Among the given options the one which is not correctly matched is Terpenes - IAA.
Let's begin the explanation by learning more about terpenes.
Terpenes are a huge and varied class of organic compounds. These are secreted by a variety of plants, for example, conifers and also by some insects. One unique property they possess is that they have a strong odour and hence protect the plants that produce them. This is achieved by deterring herbivores and by attracting predators and parasites of herbivores. They also facilitate stem elongation, germination, and help organisms overcome dwarfism. Examples of terpenes are terpineol (found in lilacs), limonene (seen in citrus fruits ), linalool (found in lavender) etc.

Additional Information
Kinetin:
-Cytokinin is a plant hormone derived from adenine. A good example of cytokinin is kinetin. It aids in cell division.
-Kinetin occurs naturally in the DNA of various cells in humans and plants.
Abscisic acid (ABA):
-Another important plant hormone is abscisic acid (ABA), it is a carotenoid derivative.
-Abscisic acid is called the stress hormone.
Indole acetic acid:
-Indole acetic acid is the best known of the auxins.
-It is a derivative of indole.
-It is insoluble in water but dissolves in ethanol.
Indole-3-butyric acid (IBA):
-Indole-3-butyric acid is used to initiate root formation in vitro in processes like micropropagation.
-The acid is not completely soluble in water. Hence, it is dissolved in 75% or more alcohol and then used for rooting.
-It is popularly used for producing new plants from tissue culture.
Ethylene:
-Its IUPAC name is ethene.
-This gas is popularly used in agriculture to force the ripening of fruits.

So, the correct answer is, ‘Terpenes - IAA.’

Note:
-Kinetin is used in plant culture to induce callus formation. It further causes the shoot generation from the callus.
-Indole-3-butyric (IBA) is a plant hormone from the auxin family. It can be extracted from willow plants.
-Indole butyric acid can be converted into indole acetic acid by beta-oxidation.
-Ethylene is a colourless inflammable gas. In pure forms, it has a faint sweet and musky odour.