They help to initiate rooting in stem cuttings, an application widely used for plant propagation. Auxins promote flowering e.g. in pineapples. They help to prevent fruit and leaf drop at early stages but promote the abscission of older mature leaves and fruits.
NTA tests whether students understand that auxins have opposite effects on fruit/leaf drop depending on the plant's developmental stage. At early stages, high auxin levels prevent abscission by inhibiting the formation of the abscission layer. However, in mature fruits and leaves, auxin concentration drops, allowing ethylene to promote abscission and senescence. The common mistake is thinking auxins always prevent fruit drop—students forget this is stage-dependent. To get it right, remember that auxin's effect on abscission is concentration and age-dependent: young organs are protected, old organs are allowed to fall naturally. This dual role makes it a high-yield NEET concept testing hormonal understanding.
Fruit and leaf drop at early stages can be prevented by the application of (NEET 2017)
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