Cell cycle and its parameters in flowering plants

Data on the duration of cell cycle and its phases in meristems are reviewed for 170 species from 93 genera of 38 families of higher plants. The reviewed cell cycle parameters are submitted in tabulated form, including taxonomic and anatomical characteristics of particular subjects, methods, experimental conditions, duration of cell cycle and its phases, and references. The influence of environmental factors on the cell cycle and temperature dependence of cell cycle parameters are considered in addition to certain features and causes of daily dynamics of mitotic index. Special attention is paid to the problem of comparability of different results of determination of cell cycle duration. As shown below, the only correct comparison of cell cycle parameters in different species is that, which is based on the evidence provided at species-specific optimum temperatures. A rather simple method for determining the optimum temperature of cell division and growth is based on the analysis of root growth rate. Critical temperature points are defined to serve for determination of optimum temperature for the cell cycle. As shown below, retardation of growth rate at low temperatures results from the proportional increase in the duration of cell cycle phases, while at the minimum temperature the morphological characteristics of meristem remain unchanged. Cell division anomalies or morphogenesis disruption that occur as cell cycle parameters change may be due presumably to the shock temperature action within the tolerant limits. Our experiments have suggested that the rhythm of illumination may exert essential influence on the parameters, structure and stationarity of the cell cycle.