A nuclear body in microsporocytes of Zea mays

Summary

• 1. A structure called a “nuclear body” has been observed in microsporocytes of two plants of Zea mays.

• 2. The nuclear body consisted of a number of globules with dark-staining walls and light-staining centers, often enveloped in a light-staining substance that was probably also composed of globules.

• 3. Single globules and small aggregates of globules were first visible among the chromosomes at late leptotene or very early zygotene. Presumably single globule-primordia arose earlier, during late premeiotic interphase and leptotene. Larger aggregates were observed in early zygotene and the nuclear body sometimes appeared to be fully formed at zygotene. The nuclear body was single, or sometimes remained in two or three parts. It decreased in size in late diakinesis and disappeared in metaphase-I.

• 4. The nuclear body contained RNA and proteins but no DNA; tests for phospholipids were not made.

• 5. The nuclear bodies in Zea and Bromus have the same appearance and probably the same chemical constitution and development.

• 6. It is suggested that the nuclear body in Zea arises from materials released by the chromosomes, and expresses synthetic activities of the chromosomes at the beginning of meiosis.