The following points highlight the six practical applications of auxins. The applications are: 1. Rooting 2. Prevention of Pre-Harvest Drop of Fruits 3. Parthenocarpy 4. Inhibition of Buds to Prevent Sprouting 5. Shortening of Internodes and 6. Selective Weed Killers.
Auxins Application # 1. Rooting:
Besides indole acetic acid, some other synthetic auxins especially naphthalene acetic acid and indole butryic acid are widely employed in initiating early and vigorous rooting in plants which are propagated by cuttings.
Auxins Application # 2. Prevention of Pre-Harvest Drop of Fruits:
Premature falling of the fruits can be checked by the application of auxins such as 2, 4-D and 2, 4 6-trichlorophenoxy acetic acid which delay the formation of the abscission layer.
Auxins Application # 3. Parthenocarpy:
Parthenocarpic seedless fruits are obtained on commercial scale by the application of auxins in many plants.
Auxins Application # 4. Inhibition of Buds to Prevent Sprouting:
Auxins like a-naphthalene acetic acid prolong the dormancy of buds in potato tubers and thus are very useful in preventing the eyes of potato tubers to sprout during storage.
Auxins Application # 5. Shortening of Internodes:
In apples and pear the fruits are developed on dwarf spurs. Treatment of the other terminal shoots with a-naphthalene acetic acid prevents the elongation of their internodes so that they also become dwarf. The latter may also bear the fruits.
Auxins Application # 6. Selective Weed Killers:
At higher concentrations the auxins may have profound herbicidal properties and are utilised in the eradication of the weeds. The significance of their activity lies in their selective toxic action on plants. For instance 2, 4-dichIoro phenoxyacetic acid. (2, 4-D) is a potent weed killer and most of the broad-leaved dicotyledonous plants which occur as weeds are killed by this synthetic auxin, but usually the cereals (which are monocotyledonous) remain unaffected.