Plant Growth Regulators

The video explains plant growth regulators, including auxins, cytokinins, gibberellins, ethylene, and abscisic acid. Auxins promote cell growth and apical dominance, while cytokinins aid in cell division and delay leaf senescence. Gibberellins enhance stem elongation and seed germination. Ethylene, a gaseous hormone, influences fruit ripening and leaf senescence. Abscisic acid acts as a growth inhibitor, inducing dormancy and reducing transpiration.

Which of the following is NOT a growth-promoting plant hormone?

• Auxins

• Cytokinins

• Abscisic acid

• Gibberellins

What is the primary role of auxins in plants?

• Promoting seed dormancy

• Facilitating cell growth and elongation

• Inducing leaf senescence

• Inhibiting root growth

How do auxins exhibit apical dominance?

• By promoting lateral bud growth

• By suppressing the growth of the apical bud

• By inducing the growth of an apical bud and suppressing lateral buds

• By inhibiting root elongation

Cytokinins were first discovered in which substance?

• Corn kernels

• Coconut milk

• Herring sperm DNA

• Rice seedlings

Which synthetic cytokinin is derived from herring sperm DNA?

• IBA

• Zeatin

• Kinetin

• IAA

What is the role of gibberellins in plants?

• Facilitating fruit ripening

• Promoting seed dormancy

• Inducing leaf abscission

• Promoting intermodal elongation

Which plant hormone is known as the stress hormone?

• Gibberellins

• Ethylene

• Abscisic acid

• Auxins