Question

Internal factors of plant depends on
a. Growth of plant
b. Genetic predisposition
c. Both
d. None of these

Answer 1

Hint: Internal factors are the intrinsic factors which help in the metabolism of the plant day to the daily life cycle, they can be some kind of chemicals produced inside. Intrinsic factors do not depend on the phenotypic genotype as phenotype affects the external physical plant such as the shape of a plant leaf, branches, whereas external factors are the sunlight, water.

Complete answer:
• Growth of plants includes the specific growth rate, change in plant physical appearance for example leaf size gets bigger, the plant gets taller these all changes can be seen in the external growth rate.
• Growth of plants is an extrinsic quality and extrinsic factors such as light, temperature, water, oxygen, carbon dioxide, pollutants, mineral salts.
• Genetic predisposition is the genetic characteristics which influence the possible phenotypic development of the plant.
• They are affected by environmental changes also.
• Whereas internal factors are the factors which are secreted inside the body and regulate its function with the help of some kind of enzymes or chemicals.
• Internal factors include nutrients which include N,P,K,CA,Mg,S,C,O,H
• It also includes micronutrients such as Fe, B, Cl, Mn, Zn, Cu, Mo, Ni
• Internal chemicals include Auxins, Gibberellins, Cytokinins, Ethylene, Abscisic acid
• These chemicals are also known as growth regulators.
• Which can be concluded that the internal factors depend on nutrients and growth regulators present in the plant body.

Hence, the correct answer is option (A).

Note: Internal growth factors are the key bases for the differentiation between a living organism and non-living organism, as in non-living things external growth can be seen by the accumulation of the matter layer over the other but intrinsic growth cannot be seen in them. The growth regulators can be promoting the growth or declining the growth by occurring pre-senescence in the plant body.