Abstract:

Callose in cell walls was observed by the callose aniline-blue fluorescence during megasporogenesis in line M14, a chromosome 9 monosomic addition line of Beta corolliflora Zoss. (Beta vulgaris L., VV+1C, 2n=18+1), in which the modes of reproduction are facultative apomixis, diplosporous and sexual reproduction. The results are as follows: Allium odorum-type. Callose first occurs in the wall of megasporocyte from the micropylar end, then gradually envelops the whole cell. Megasporocyte is surrounded by the wall with callose during metaphaseⅠ, anaphaseⅠ and telephaseⅠ. At dyads stage, callose in micropylar end begins to disappear, and callose fluorescence displays in the transverse walls between dyads and side walls of the diplosporous functional megaspore in chalazal end. As development goes on, callose fluorescence disappears in the chalazal wall of diplosporous functional megaspore. No callose fluorescence shows in the wall of mononuclear embryo sac after its formation, while thick callose deposits in the wall of the degenerative megaspore. Antennaria-type. There is no callose deposition in the wall from megasporocyte stage to diplosporous functional megaspore stage all along. Polygonum-type. During the process of megasporocyte meiosis, callose occurs first in the wall of megasporocyte from micropylar end, then gradually envelops the whole cell. Callose exists mainly in transverse walls during dyad, triad and tetrad stages, a little in side walls. Thick callose deposits in the walls of degenerative megaspores, while little in the wall of functional megaspore. In addition, correlations between the meiosis and callose deposition in the wall of megasporocyte have been discussed.

Key words: Monosomic addition line in sugar beet（Beta vulgaris L, VV+1C, 2n=18+1）, Facultative apomixis, Megasporogenesis, Callose