Before You Begin
Question #46272
The Question
During the grain-filling stage in Zea mays, a severe environmental stress impairs the regeneration of phosphoenolpyruvate (PEP) in the C4 pathway. Due to the resulting deficit in sucrose loading into the phloem, the developing seed (sink) experiences a severe shortage of photoassimilates. Which of the following is the most likely consequence of this physiological deficit on seed embryology?
Options
- A.
Truncated differentiation of the radicle and hypocotyl due to compromised maintenance of the quiescent center.
- B.
Increased photorespiratory loss within the developing embryo due to the oxygenase activity of RuBisCO in the mesophyll cells.
- C.
Hypertrophy of the coleorhiza to actively absorb residual nutrients directly from the maternal tissue.
- D.
Premature degeneration of the synergids and antipodals, leading to the abortion of double fertilization.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Seed Embryology|C4 Pathway Efficiency|Root Region Differentiation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Plant Physiology (Source-Sink dynamics & C4 Kranz anatomy) with Plant Reproduction (Embryogenesis).
The question tests the student's ability to trace a biochemical deficit (PEP regeneration) to a morphological outcome (embryonic axis truncation).
It utilizes a Chronological Trap (Option D confuses pre-fertilization with post-fertilization) and a Location Trap (Option B exploits the classic misconception of RuBisCO's location in C4 leaves).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Seed Embryology |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |