Therefore, its protein content, oil content, carbohydrate content and various other substances of nutritional importance must be tested before proper selection. Plant physiology thus plays an important and essential role in specifying the features for which the plant breeder must select the crop.
2. Role in Soil Fertility:
Our knowledge of mineral nutrition of different crop plants provided extensive revisions in the application of fertilizers. It is now possible to recommend specific organic fertilizers or inorganic salts using knowledge of plant physiology.
3. Role of Auxins:
(a) Auxins are used to prevent premature fruit drop, when applied close to the time of harvest. (b) Auxins (Particularly IBA) induce formation of roots on cuttings of many ornamental, horticultural and forest trees.
(c) Many auxins are used to promote sprouting, induce flowering and enhance yield in potatoes, peas, beans, etc.
4. Role of Gibberellins:
(a) Gibberellins are used to break dormancy and induce uniform crop emergence, e.g., seed potatoes. (b) It is used to enhance the growth of vegetative parts of several floricultural species and used to increase flower size.
(c) Gibberellins are also used to produce parthenocarpic (seed-less) fruits. (d) Cytokinins have less importance in agriculture. It is used in extending selflife of lettuce, tomatoes, apples, etc. It is also used to induce efficient root system in maize and rice.
5. Role of Ethylene:
(a) Ethylene is a hormone which is well known to cause fruit ripening. (b) Ethylene causes abscission. (c) It is used to induce bulbing in onion. (d) Ethylene increases tillering in rye, peas, etc.
6. Role of inhibitors:
(a) A well known inhibitor CCC (2-chloroethyl-tri methyl ammonium chloride) is used to induce stiffening of plants, increase number of roots and litters, prevent lodging and increase yield in wheat, oat and several strains of Secale (rye). (b) CCC is also used to increase bolting, flowering and increase yield in cotton.
(c) Many inhibitors, such as, CCC, phosphon, B-9, etc. are used in ornamental horiculture to retard the height of plants like chrysanthemum.
7. Role in Seed Production:
Knowledge of plant physiology is used in production of high quality, viable and pure seeds from weed seeds.
8. Role in food Technology:
Plant physiology provides many techniques required for food preservation, food processing, such as drying, pickling and food storage.