Prepare for NEET Biology Plant Growth and Development (Seed Dormancy) with MCQs & PYQs on NEET.GUIDE. Access free practice, previous year questions, and expert solutions to understand factors preventing germination and dormancy breaking methods.
NEET Questions / Botany / Plant Growth and Development / Seed Dormancy
A dormant seed of a desert plant imbibes water but fails to germinate even under optimal temperature and oxygen availability. Which of the following is the MOST LIKELY explanation for this continued dormancy?
Insufficient light exposure to trigger phytochrome conversion.
Presence of inhibitors like abscisic acid in the seed coat.
Immature embryo requiring a period of after-ripening.
Hard seed coat impermeable to oxygen, preventing respiration.
Which of the following combinations of factors is MOST LIKELY to break seed dormancy in a species exhibiting combinational dormancy?
Exposure to high temperatures followed by gibberellic acid application.
Scarification followed by exposure to high oxygen levels.
Cold stratification followed by exposure to light.
Soaking in water followed by exposure to ethylene.
The ratio of ABA to GA in a dormant seed is typically high. Which of the following changes during seed germination is MOST directly responsible for shifting this balance and promoting growth?
Increased ABA degradation and decreased GA degradation.
Increased GA biosynthesis and decreased ABA biosynthesis.
Transport of ABA out of the embryo and GA into the embryo.
Inactivation of ABA receptors and activation of GA receptors.
Some seeds require a specific duration of light exposure to germinate. If a flash of red light (R) is given, followed immediately by a flash of far-red light (FR), what is the MOST LIKELY effect on germination?
Germination will be stimulated.
Germination will be inhibited.
Germination will be unaffected.
The effect will depend on the seed species.
A researcher observes that a batch of dormant seeds fails to germinate even after scarification and exposure to favorable conditions. Suspecting the presence of a volatile inhibitor, which experimental setup is MOST appropriate to confirm this hypothesis?
Grind the dormant seeds and apply the extract to non-dormant seeds.
Place the dormant seeds in a closed container with non-dormant seeds of a different species and observe germination rates.
Expose the dormant seeds to high concentrations of ethylene gas.
Soak the dormant seeds in a solution of gibberellic acid.
In some plant species, seed dormancy is broken by the action of microorganisms in the soil. Which mechanism is MOST LIKELY involved in this process?
Microbial production of gibberellins that stimulate germination.
Microbial degradation of germination inhibitors in the seed coat.
Microbial enhancement of oxygen availability to the embryo.
Microbial scarification of the seed coat, allowing water imbibition.
Which of the following is NOT a method used by plants to overcome seed dormancy?
Scarification of the seed coat
Stratification or exposure to low temperatures
Exposure to high concentrations of abscisic acid
Leaching of inhibitory substances
The hard seed coat of some seeds acts as a barrier to:
Water uptake only
Oxygen uptake only
Both water and oxygen uptake
Light penetration
Which of the following is an example of a chemical inhibitor that can cause seed dormancy?
Gibberellins
Cytokinins
Abscisic acid
Ethylene
Seed dormancy is an adaptation that primarily ensures:
Immediate germination upon seed dispersal
Germination under favorable environmental conditions
Prevention of seed predation
Increased seed dispersal distance
