Table 1 Meiotic staging criteria for wild type Arabidopsis thaliana prophase I substages
Meiotic staging criteria | Sub-stages of prophase I | ||||
|---|---|---|---|---|---|
Leptotene | Zygotene | Pachytene | Diplotene | Diakinesis | |
Tapetal cell nuclei | Mononuclear | Mononuclear (early)Few binuclear (mid)Many binuclear (late) | Binuclear | Binuclear | Binuclear |
Callose wall thickness | Very thin | Thin | Thick | Thicker | Thickest |
Nucleolus position | Central (early)Peripheral (late) | Peripheral | Peripheral (early) Peri-central (late) | Central | Central |
Nucleolus shape | Round | Round (early) flattened (late) | Flattened (early) round (late) | Round | Round |
Chromosome distribution in the nucleus | Circular and takes up entire nuclear space | Crescent shape in one hemisphere of nuclear space | Roughly circular but does not take up entire nuclear space | Takes up more of nuclear space than in pachytene | Five distinct bivalents distributed in nuclear space |
Chromosome thickness | Thin | Mixture of thin and thick | Thick | Mixture of thin and thick (early) Thick (late) | Very thick |