Why subculturing resembles propagation by cuttings—choose the best reason In micropropagation, which statement best explains why subculturing is considered analogous to propagation by cuttings in conventional horticulture?
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AIt separates multiple microshoots and places each on fresh medium for independent growth
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BIt uses scions to produce new microshoots on rootstocks
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CBoth use identical in vitro conditions from start to finish
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DAll of the above
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ESubculturing always involves graft unions
Answer
Correct Answer: It separates multiple microshoots and places each on fresh medium for independent growth
Explanation
Introduction / Context:Subculturing (multiplication stage) in micropropagation parallels the logic of taking cuttings: you partition a parent shoot into smaller, autonomous units that then root or elongate into new plants. Understanding this analogy clarifies workflow design in the tissue culture lab.
Given Data / Assumptions:
- Microshoot clusters are produced on cytokinin-rich media.
- Subculture involves dividing these clusters and transferring to fresh medium.
- Conventional cuttings also partition a plant into units that can root and grow independently.
Concept / Approach:Focus on the operational similarity: physical separation of propagules and providing a growth-supportive environment. Unlike grafting/budding, no scion-rootstock union is created during subculture.
Step-by-Step Solution:
Identify the act of subdividing shoots (analogous to taking cuttings).Transfer each unit to optimized medium (analogous to rooting medium in cuttings).Allow independent development into plantlets, then root and acclimatize.Verification / Alternative check:Protocols describe regular subculture intervals where clusters are divided; this mirrors nursery schedules for taking and rooting cuttings.
Why Other Options Are Wrong:
- (b) Refers to grafting terminology; not part of subculture.
- (c) Conventional cuttings are ex vitro, not in vitro.
- (d) and (e) overstate or misstate the practice.
Common Pitfalls:Assuming subculturing equals grafting or that all propagation occurs in vitro; the analogy is about partitioning shoots, not method identity.
Final Answer:It separates multiple microshoots and places each on fresh medium for independent growth