Multiple Choice QuestionsAbscisic acid is known as the stress hormone because it
breaks seed dormancy
induces flowering
promotes leaf fall
promotes closure of stomata
Which of the following plant growth regulators (PGRs) promotes root initiation, flowering and induced parthenocarpy?
Gibberellin
Auxin
Cytokinin
Ethylene
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.
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
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.
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
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
B.
If both assertion and reason are true but reason is not the correct explanation of assertion
Vernalization is coolong of seed during germination in order to accelerate flowering when it is planted.
In colder countries, there are cereals of 2 physiological types, i.e., winter cereals and spring
cereals. Winter cereals are sown in winter and flower in following summer whereas spring cereals are sown in spring and flower in summer.
If winter cereal are sown in spring, it shows vegetative growth but does not flower unless it receives low temperature of winter. However, they can be converted into spring cereal by providing artificial low temperature treatment, (i.e., springification.)
Some plants requiring low temperature requirement (vernalization) for flowering are Secale cereale (European rye), Triticum vulgare, Brassica oleracea, Beta vulgaris, Apium and Lolium perenne, etc.
Site of vernalization is apical meristem or all the meristematic cells. As a result of vernalization, a flowering hormone called "vernalin" is formed (reported by Melchers), but venalin has never been isolated. Once a plant is vernalized, it can be devernalized by exposing the plant to temperature of 30C or above. For establishing vernalization, plant should be kept at 20°Cfor 4-5 days.
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