Apomixis and Polyembryony - Unsolved Practice Set
Chapter: Sexual Reproduction in Flowering Plants | Topic: Apomixis and Polyembryony
APOMIXIS AND POLYEMBRYONY - UNSOLVED PRACTICE SET
Topic: Apomixis and Polyembryony
Multiple Choice Questions
Q1. The phenomenon of seed formation without fertilisation is called:
- Parthenocarpy
- Apomixis
- Double fertilisation
- Pollination
Q2. In many citrus and mango varieties, additional embryos often develop from:
- Synergids
- Nucellus cells
- Antipodal cells only
- The pollen tube
Q3. The occurrence of more than one embryo within a single seed is termed:
- Apomixis
- Polyembryony
- Parthenocarpy
- Xenogamy
Q4. Apomixis is of great interest to plant breeders mainly because it helps:
- Increase genetic variation
- Fix hybrid vigour by producing clonal seeds
- Promote cross-pollination
- Prevent seed formation
Q5. A form of apomixis in which the embryo develops directly from a diploid egg cell without meiosis and fertilisation is called:
- Adventive embryony
- Diplospory
- Apospory
- Parthenocarpy
Short Answer Questions
Q6. Define apomixis, and explain how it results in seeds that are genetically identical to the mother plant.
Q7. What is polyembryony? Give one common example of a plant showing this phenomenon.
Q8. Why is apomixis considered agriculturally significant for hybrid seed production companies?
Q9. Name one family or group of plants in which apomixis is commonly observed.
Long Answer Questions
Q10. Explain how polyembryony can arise in citrus and mango seeds, describing the role of nucellar tissue in forming additional embryos.
Q11. Discuss why apomixis is described as a form of asexual reproduction even though it occurs through seeds, and explain its potential importance for maintaining hybrid vigour across generations.
APPLICATION / ANALYSIS
Q12. A mango seed, when cut open, is found to contain more than one embryo of slightly different sizes. Using your understanding of polyembryony, suggest which tissue, other than the zygote, might have given rise to the additional embryo(s).
Q13. Seed companies invest heavily in producing hybrid seeds every year because hybrid vigour is lost when farmers save and replant seeds from a hybrid crop. Explain how successfully introducing apomixis into hybrid crop varieties could help solve this problem for both companies and farmers.