The course of the first meiotic prophase in Beta procumbens and in the F1 between B. vulgaris and B. procumbens

Abstract

The succession of the stages of the first meiotic prophase in Beta procumbens has been ascertained by measurements of the nuclear volume and by other criteria. By this method it has been possible to relate the appearance of pairing gaps to the beginning separation of the chromosomes after pachytene. A zygotene-like stage of early diplotene has been found. Asynchronous condensation of the bivalents and reduction of the chiasma frequency have been observed in diplotene and diakinesis. - The lengths and arm ratios of the pachytene chromosomes of Beta procumbens were determined.Stages similar to those in B. procumbens have been recognized in the F 1 hybrid between Beta vulgaris and Beta procumbens. The pachytene chromosomes appeared to be paired to a great extent. However, only some of the cells showed bivalents in diakinesis, in the majority desynapsis occurred during diplotene or early diakinesis. In metaphase I, bivalents, univalents, cases of secondary association due to stickiness and cases of fragmentation have been observed.

Sequential analysis of meiotic prophase in grasshoppers.

“…Based on this arrangement, we have established as the first phase the synizesis, a meiotic stage in which the homologous chromosomes appear apparently paired. This stage has been previously described by other authors and it was also placed at the beginning of meiosis (Swanson 1958, Moens 1964, Nagl 1969, Lacadena and Vazquez 1971, Owens and Molder 1971, Maguire 1972). …”

“…The pair ing continues increasing gradually from one to another, there not being possible to establish the presence of the schizonema stage as observed in other species (Moens 1964, Nagl 1969, Whelan and Hornby 1969, Lacadena and Vazquez 1971.…”

“…Nevertheless other authors refer to the diffuse stage as a special stage within the meiotic cycle (Moens 1964, Ghidoni 1967, Lu 1967, Pijnacker 1967, Peacock 1968, Nagl 1969, Whelan and Hornby 1969, Barry 1969, Lu and Raju 1970, Pogosianz 1970, Klasterska 1971, Lacadena and Vazquez 1971, Owens and Molder 1971, Kezer and Macgregor 1971, Koch et al, 1972, Baker and Franchi 1972, Zickler 1973, Jones 1973Sotelo et al 1973;... See reviews by Klasterska 1976Klasterska , 1977. Not all the authors locate the diffuse stage between the same phases, although the majority place it between pachytene and diplotene.…”

Development of male gametophyte of Larix leptolepis Gord. with emphasis on diffuse stage of meiosis

“…4 Rep (2008Rep ( ) 27:1687Rep ( -1696Rep ( 1693 longitudinally separated homologous threads as described by Moens (1964). This stage has been described in male meiosis of many organisms (Moens 1964;Barry 1969;Nagl 1969;Sen 1969;Pogoslanz 1970;Klášterská and Natarajan 1974;Oud et al 1979;Cawood and Jones 1980;Cardoso et al 1986). Pre-diffuse diplotene is the transition from the early diplotene into the diffuse stage, during which the chromosomes despiralize and reorganize with the (Klášterská 1976;Seitz et al 1996;Cattani and Papeschi 2004;Král et al 2006).…”

Acetocarmine squash method for observing sugar beet chromosomes

“…Aceto-orcein staining has also been used by ROMMEL (1963) for somatic chromosome study in very young leaf or shoot tip cells. On the other hand, for meiotic chromosome studies the acetocarmine squash method has been mainly used (LEVAN, 1942 ;NAGL, 1969;WAL1A, 1970WAL1A, , 1971. Other researchers used the orcein squash technique for meiotic chromosome study (FILUTOWICZ, 1971).…”