The cells of the quiescent centre are characterised by
having dense cytoplasm and prominent nuclei
having light cytoplasm and small nuclei
dividing regularly to add to the corpus
dividing regularly to add to tunica
B.
having light cytoplasm and small nuclei
In the apices ofsome roots, (e.g., Zea mays, maize), there is a central region of cells which normally does not divide. This central inactive region was called quiescent centre by FE.A.L. Clowes (1959, 1961).
The cells of this region have lesser amounts of RNA and DNA so they have small nuclei. These cells also have a lower rate of protein synthesis. Mitochondria and endoplasmic reticulum arc less developed. The cells of the quiescent centre arc usually inactive. However, if already existing meristematic cells are injured or become inactive due to any other reason, the cells ofquiescent centre become active.
Which of the following plant growth regulators (PGRs) promotes root initiation, flowering and induced parthenocarpy?
Gibberellin
Auxin
Cytokinin
Ethylene
Abscisic acid is known as the stress hormone because it
breaks seed dormancy
induces flowering
promotes leaf fall
promotes closure of stomata
Refer the given figures on photoperiodism and select the correct option.
| A | B | C |
| no correlation between light period and flowering | long light- exposure period | short light- exposure period |
| A | B | C |
| long light- exposure period | no correlation between light period and flowering | short light- exposure period |
| A | B | C |
| short light exposure period | long light exposure period | no correlation between light period and flowering |
| A | B | C |
| no correlation between light period and flowering | short light exposure period | long light exposure period |
Assertion: Plant growth as a whole is indefinite.
Reason: Plants retain the capacity of continuous growth throughout their life.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
Which one of the following methods is commonly used to maintain the genetic traits of a given plant
By propagating through seed germination
By propagating through vegetative multiplication
By generating hybrids through intergeneric pollination
By treating the seeds with gamma radiations
Phytohormones are
hormones regulating growth from seed to adulthood
growth regulators synthesised by plants and influencing physiological process
hormones regulating flowering
hormones regulating secondary growth.
Assertion: Cytokinins increases shelf life of fruits and vegetables.
Reason : Cytokinins induce cell division.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : Vernalization is acceleration of subsquent flowering by low temperature treatment.
Reason : Site of vernalization is apical meristem.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
