Question

Artificial application of auxin like IAA, IBA and NAA to unpollinated pistils can form:
A. Fruits with much flesh
B. Larger fruits
C. Sweet fruits
D. Seedless fruits

Answer 1

Auxin is a plant hormone produced in the stem tip that promotes cell elongation. They occur naturally as well as synthetic. Artificial application of auxins causes parthenocarpy in some plants. It is a very important hormone required for the growth and development of plants.

Complete step by step answer: During the growth of a plant various complex body organizations produce factors that govern and control the development of a plant body. These factors can be intrinsic (internal) or can be extrinsic (external factors). The intrinsic factors include intracellular factors like genetics and plant growth regulators, whereas extrinsic factors include light, temperature, water, oxygen, nutrition, etc. Plant growth regulators or plant hormones or phytohormones are small and simple molecules of varying chemical compositions which cause various changes in the plant body. For example auxins, gibberellins, cytokinins, etc. Auxin was first isolated from human urine. It is basically IAA or indole acetic acid that has growth causing activities. IAA (indole acetic acid), IBA (indole butyric acid) are isolated from plants whereas NAA (naphthalene acetic acid) and 2, 4-D (2, 4-dichlorophenoxyacetic) are synthetic auxins. Auxins initiate rooting in stem cuttings, promote flowering and prevent dropping of fruits and leaves at early stages. Further, auxins also induce parthenocarpy, i.e. they turn unpollinated pistils into seedless fruits which carry more market price than the seeded fruits.
Therefore, the correct answer is option D.

Note: The list of the requirements for plant growth includes water, oxygen, nutrients such as macronutrients and micronutrients. Water creates turgidity in the cell which helps them to grow in size. Water also helps the enzymes to work efficiently. Oxygen aids in the release of metabolic energy essential for growth. Nutrients are the source of the synthesis of protoplasm and also a source of energy. In addition, every plant has its optimum temperature range suited best for its growth along with environmental signals like sunlight and gravity which affect phases of growth.