关键词: 烟草, 中央细胞, 离体培养, 膜结合钙, 钙调素

Abstract: We used chlorotetracycline(CTC), fluphenazine(FPZ), calcofluor white ST(CW), DAPI and other probes to label the membrane-bound calcium, calmodulin(CaM), cell wall, nucleus and other components respectively which distributed in the isolated central cells before and after fertilization and in vitro cultured unfertilized central cells of Nicotiana tabacum var.macrophylla.Cell wall of the isolated central cells could be detected even when the cells turned to spherical shape.After a period of culture, two polar nuclei seperated, then moved to the micropylar and the chalazal part of the central cell respectively.Undergone one or several times of division, the nuclei showed various sizes and shapes.Stained with I-KI and Sudan Ⅲ, unfertilized central cells contained a few of starch grains around the polar nuclei, but no lipid component was detected.When the central cell divided into small cell clusters in vitro, starch grains accumulated abundantly in sharp contrast to the endosperm cells at the elongated-zygote stage, which were rich of protein but lack of starch.Membrane-bound calcium and CaM were mainly located at the cytoplasm and cytoplasmic strands in either the in vivo or the in vitro developed central cells.Unfertilized egg apparatus was studied by the way.The cells had plentiful protein but few starch grains and lipid component.The distribution of membrane calcium and CaM showed no difference between two synergids before fertilization;while after fertilization, the degenerated synergid showed higher CTC fluorescence but weaker FPZ fluorescence than the persistent synergiddid.The zygotes were observed to contain a lot of protein and lipid.

Key words: Nicotiana tabacum, Central cell, In vitro culture, Membrane-calcium, Calmodulin