Variability of the number of chloroplasts in a population of stoma guard cells in the sugar beet (Beta vulgaris L.)

Diploid sugar beet plants demonstrate a broad variability of the number of chloroplasts in stoma guard cells, which is related to myxoploidy of cell populations in leaf apical meristems (epigenomic variability). In addition to random organelle segregation between daughter cells, this variability is affected by factors disrupting the mitotic cycle: (1) plant treatment with a mitotic poison, such as colchicine; (2) duration of the life cycle of a plant; the variability in second-year plants is greater than in first-year ones; (3) the mode of plant reproduction; the variability in inbred plants is greater than in the initial population. Treatment of germinating seeds with a diluted colchicine solution increases the number of organelles in cells in the myxoploid generation (generation C0) and the variance of the distributions in the first vegetation year. The variability in the organelle number in stoma cells correlates with that in maternal meristem cells. It is concluded that the epidermal cell monolayer (including stoma guard cells) keeps record of the epigenomic and epiplastome variability in meristem cells. The variability of the number of chloroplasts in stoma guard cells is approximated by binomials with negative powers.