Question

Discuss the practical applications of auxins in Agriculture and Horticulture.

OR

What are auxins? Explain briefly uses of Auxins.

Answer 1

Auxins are a group of plant growth substances, acidic in nature and bring about over-all growth. 

• Apical dominance:
• As long as the apical bud is present growth of lateral buds is pre-vented which is used in the long term storage of potato tubers.
• Rooting:
• In low concentrations, auxins stimulate root formation which is used to propagate cuttings. When dipped in a dilute solution of auxins the root formation is initiated.
• Flower initiation:
• Low Concentration of 2, 4-D and NAA are used to initiate flowering in a pineapple so that harvesting becomes easy.
• Abscission:
• Application of auxins increase the concentration and thereby delays the development of abscission which prevents premature leaf and fruitful. This is used in orchards and prevention of defoliation in cabbages and cauliflower.
• Parthenocarpy:
• This is the process of obtaining fruits without fertilization and gives rise to seedless varieties which is successfully used in citrus, dates.
• Sex expression:
• Use of auxins on cucurbit plants increases the production of female flower.
• Weedicide / Herbicide:
• 2-4-D is widely used as a herbicide on broad-leaved forms because of its non-toxic nature. Widely used in crop plant cultivation or lawns. 
• Tissue culture (organogenesis):
• In tissue culture where micropropagation is carried out the auxins are used to bring about organogenesis.