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.
Related Questions
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
Which of the following is not an inhibitory substance governing seed dormancy ?
Gibberellic acid
Abscisic acid
Phenolic acid
Para-ascorbic acid
Which one of the following inhibits seed germination for a particular period?
Light
Water
Caron dioxide
Dormancy
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.
Which of the following is an example of a chemical inhibitor that can cause seed dormancy?
Gibberellins
Cytokinins
Abscisic acid
Ethylene
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
Which of the following substances does not typically contribute to seed dormancy?
Abscisic acid
Phenolic acids
Short-chain fatty acids
Gibberellins
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.
For cryopreservation, plant materials are frozen at
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.
