Plant Growth and Development Class 11 Biology Important Questions

Objective Questions

Question. Cytokinins are formed primarily in which area of the plant?
(a) Tips of shoot
(b) Root
(c) Stem
(d) Lateral buds and leaves

Question. Natural cytokinins are synthesised in
(a) Root apices
(b) Developing shoot buds
(c) Young fruits
(d) All

Question. Zeatin is
(a) An auxin
(b) a GA
(c) a cytokinin
(d) None

Question. Cytokinins help to produce all except
(a) New leaves
(b) Chloroplast in leaves
(c) Lateral shoot growth and adventitious shoot formation
(d) Rooting on stem cut

Question. C₂H₄ is synthesised in large amount by-
(a) Shoot tip
(b) Root tip
(c) Young leaves
(d) Tissues undergoes senescence and ripening fruits

Question. During ripening of the fruits, rate of respiration is increased under the influence of hormone. The hormone is
(a) ABA
(b) Auxin
(c) C₂H₄
(d) GA

Question. Seed dormancy is regulated by-
(a) C₂H₄
(b) ABA
(c) IAA
(d) GA₃

Question. The most widely used compound as a source of C₂H₄ is
(a) Kinetin
(b) Zeatin
(c) IBA
(d) Ethepon

Question. Which hormone promotes female flowers in cucumber?
(a) ABA
(b) C₂H₄
(c) GA₄
(d) GA₃

Question. Long day plants flower specially when the?
(a) Light period is lesser then some critical length
(b) Light period is grater then some critical period
(c) Dark period is less then some critical length
(d) Dark period is more then some critical length

Question. The following diagram shows four coleoptile set up at the start of an experiment

Which two coleoptile will both bend towards the light source?
(a) 1 and 2
(b) 1 and 4
(c) 2 and 3
(d) 3 and 4

Question. Removal of auxin source demonstrates that leaf abscission is _____ by auxin, and apical dominance is _____ by auxin
(a) Promoted, promoted
(b) Inhibited, inhibited
(c) Promoted, inhibited
(d) Inhibited, promoted

Question. Branching is inhibited by _____ from the tip of a growing shoot but this effect is encountered by _____ from the root
(a) Cytokine, auxin
(b) Auxin, Cytokine
(c) GA, Cytokine
(d) GA,ABA

Question. Which of the following plant hormones can cause the base of a shoot to form new early stage, to be used as herbicide / weedicide, also controls xylem differentiation and helps in cell division?
(a) GA
(b) Cytokine
(c) Auxin
(d) ABA

Question. Removal of shoot tips (decapitation) means loss of apical dominance and it is widely applied in
(a) Tea plantation
(b) Hedege-making
(c) Both
(d) Bolting

Question. Which one(s) is acidic in nature?
(a) Ausin
(b) GA
(c) ABA
(d) All

Question. Which GA was the first Giberrellin to be discovered?
(a) GA₁
(b) GA₂
(c) GA₃
(d) GA₄

Question. The fruits can be left on the tree longer so as to extend the marked period. This is due to which function of GA?
(a) Bolting
(b) Delay senescence
(c) Internodal elongation
(d) Parthenocarpy

Question. Spraying surgarcane with gibberellin increases the yield by as much as 20 tonnes per acre. GA makes this possible
(a) By improving the quality of fruit
(b) By making plants with rosette habit
(c) By internodal elongation
(d) None

Question. Which one is false?
(a) GA₃ is used to speed up the malting process in brewing industry
(b) Spraying juvenile conifers with GA₃ hastens the maturity, thus leading to early seed production
(c) GA₃ is commercially available gibberellin
(d) GA₃ cannot increase the length of internode in sugarcane

Question. Two cytokinins are kinetin and Zeatin. What is the difference between the two?
(a) Kinetin is the active from of zeatin
(b) Zeatin is the active from of kinetin
(c) Zeatin is synthetic cytokininand kinetin is naturally occurring
(d) Zeatin is naturally occurring plant cytokinin, kinetin is not