Growth in the Archaeplastida, excavata, chromalveolata, and Amoebozoa

Growth in the unicellular chlorophytes is synonymous with binary fission, budding or multiple fission.  In most unicells, haploid or diploid nuclei undergo mitosis, and the cell then divides longitudinally to form two daughter cells. In some species there are two haploid divisions within the parent cell, followed by the formation of four motile daughter cells. Multiple fission occurs where the nucleus divides several times with- out cell division. Cell division occurs after the formation of multiple nuclei. Some species produce buds, where the mitotic nucleus migrates to a bud forming on the parent cell surface. Some coenocytic filamentous species grow from the tip of the filament in a way very similar to that of hyphal growth. Others grow by division of vegetative cells within filaments or sheets. Accurate estimates of their growth rates can be made by cell counting or by estimating chlorophyll content of a culture. The kinetics of growth is similar to those seen in the bacteria. However, for photosynthetic species, it is the depletion of nutrients other than carbon that leads to growth limitations and the onset of the stationary phase and cell death. Nitrogen, phosphates or silicon are frequently limiting.