Meiosis inCrepis - I. Pachytene association and chiasma behaviour inCrepis capillaris (L.) Wallr. andC. tectorum L
1. Meiosis is normal and has been followed through all stages from pachytene to second metaphase inCrepis capillaris (L.) Wallr. andC. tectorum L. A quantitative analysis of chiasma behaviour has been made for each kind of bivalent. Chiasma frequency is low, the majority of bivalents inC. capillaris having only one chiasma.
2. The satellitedD chromosomes in both species are observed to be attached to the nucleolus at both the first and the second meiotic divisions.
3. The two chromosomes of a bivalent are coiled about one another in the early stages. Uncoiling is gradual and complete by diakinesis.
4. Bivalents of theC chromosomes have single terminalised chiasmata at mid-diakinesis, whereas single chiasmata in the longerA andD bivalents rarely terminalise.
5. Similar chromosomes ofC. capillaris andC. tectorum show closely similar mean chiasma frequencies during diakinesis, and the same types of bivalent configuration.
6. Chiasma frequency at mid-diakinesis is almost directly proportional to length.
Volume 100, 2021
Continuous Article Publishing mode
Click here for Editorial Note on CAP Mode