Prophase I of Meiosis during Megasporogenesis Is Defective in arp6.
(A) and (B) Wild-type megasporocyte in the leptotene and pachytene stages, respectively, of prophase I.
(C) Wild-type megasporocyte in the diakinesis stage of prophase I containing five pairs of bivalents.
(D) and (E) Apparently normal arp6-1 megasporocytes in leptotene and pachytene stages, respectively, of prophase I.
(F) An apparently normal arp6-1 megasporocyte in the diakinesis stage of prophase I.
(G) A defective arp6-1 megasporocyte in the diakinesis stage of prophase I showing disorganized chromosomes with some linked to each other with chromosomal bridges (black arrow).
(H) A defective arp6-2 megasporocyte in the diplotene stage of prophase I showing a mixture of univalent and bivalent; black asterisks point to univalents.
(I) A defective arp6-2 megasporocyte in the late prophase I stage containing disorganized and fragmented chromosomes.
Bar in (A) = 10 μm for (A) to (I).