Class 11 Biology Plant Physiology Plant Growth and Development



Assertion: The seed dormancy helps the seeds to survive through an unfavourable season. e.g., a very cold winter or a very hot summer.
Reason: The dormancy of the seeds is regulated by hormones or by temperature and restricted oxygen uptake by hard seed-coat.
(a)
If both A and R are true and R is correct explanation of A.
(b)
If both A and R are true but R is not correct explanation of A.
(c)
If A is true and R is wrong.
(d)
If both A and R are wrong.
(e)
If A is wrong and R is true.
Correct answer: (a) 
Solution: A dormant seed is one that is unable to germinate in a specified period of time under a combination of environmental factors that are normally suitable for the germination of the non-dormant seed. Dormancy is a mechanism to prevent germination during unsuitable ecological conditions, when the probability of seedling survival is low. Dormancy is a seed characteristic which defines the conditions required for germination and therefore, any cue that widens the environmental requirements for germination should be regarded as a dormancy release factor. A wide range of factors can therefore, alter (physiological) seed dormancy, e.g., temperature, light, nitrate or naturally occurring chemical signals (ABA and four other terpenes) in leachate from litter that covers the seeds in their habitat.
Thus, the correct answer is option A.

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play store logo
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plant growth and development
respiration in plants
transport in plants
anatomy of flowering plants
photosynthesis in higher plants