Plant Growth and Development

More Topic from Biology

Question 1

'Foolish seedling' disease of rice led to the discovery of

  • GA

  • ABA

  • 2, 4-D

  • IAA

Solution

A.

GA

Gibberellins (GA) were first isolated from the fungus Gibberella fujikuroi the causal organism of foolish seedling disease of rice plants in Japan by kurasawa in 1926.

Question 2

A drupe develop in 

  • Wheat

  • pea

  • tomato

  • Mango

Solution

D.

Mango

In mango, coconut, plum, etc., the fruit is known as drupe (stony fruit).They develop from monocarpellary, superior ovaries and are one seeded. In mango, the pericarp is well differentiated into an outer thin epicarp, a middle fleshy edible mesocarp and an inner stony hard endocarp.

Question 3

A few normal seedlings of tomato were kept in a dark room. After a few days they were found to have become white - coloured like albinos. Which of the following terms will you use to describe them?

  • Mutated

  • Embolised

  • Etiolated

  • Defoliated

Solution

C.

Etiolated

Etiolation is a process in which flowering plants are grown in the parital or complete absence of light. Etiolation is mainly characterised by long and weak steam and smaller, sparse pale yellow colour (chlorosis) leaves due to longer internodes.

Question 4

Auxin can be bioassayed by

  • Avena coleoptile curvature

  • Hydroponics

  • Potometer

  • Lettuce hypocotyl elongation

Solution

A.

Avena coleoptile curvature

Auxin is a phytohormone that is often bioassayed by Avena coleoptile curvature test. The angle of curvature of a decapitated oat coleoptile is measured after placing an agar block containing auxin on one side. The ability of auxin to stimulate shoot growth is then measured.

Question 5

During seed germination its stored food is mobilised by

  • ethylene

  • cytokinin

  • ABA

  • gibberellin

Solution

D.

gibberellin

Gibberellin induces aleurone cells to secrete an enzyme to break stored food in the seed. Cytokinines promote nutrient mobilisation, which helps in the delay of leaf senescence. 
ABA plays an important role in seed development, maturation and dormancy. Ethylene induces fruit ripening, breaks seed dormancy.