ISHS Acta Horticulturae 393: Environmental Effects and their Control in Plant Tissue Culture
COMPONENTS OF WATER POTENTIAL RELATED TO TISSUE DIFFERENTIATION AND CELL EXPANSION IN TISSUE CULTURE |
| Authors: | H. Nonami, T. Ikeda, A. Maejima, T. Fukuyama, Y. Hashimoto |
| Keywords: | embryogenesis, growth-induced water potential, isopiestic psychrometer, MS salts, paper wick method, pressure probe, water potential |
| Abstract:
Although water moves along the water potential gradient, when plant cells are submerged in solution or placed directly on a culture medium, the permeability of ions through membranes may significantly influence the determination of water potential of cells. If a solution contains substances that are readily absorbed by cells, such substances may not act as osmotic agents against plant cells. Under tissue culture conditions, plant cells are exposed to substances that could be readily absorbed or metabolized by cells. Carrot embryos (Daucus carota L.) and soybean (Glycine max Merr.) embryos were cultured in a medium based on MS salts. Cell water potential, osmotic potential and turgor were measured by using the psychrometer, the pressure probe and the picoliter osmometer. When cells were cultured, the water potential of the medium decreased initially, and then gradually increased. Water potentials of cells became more positive compared with the water potential of the medium when the concentration of the medium was increased. This indicates that some components of the medium were readily absorbed by the cell as rapidly as water entered the cell during morphogenesis and cell expansion. Thus, concentrations of chemical components may not necessarily indicate the osmotic stress for plant cells under tissue culture conditions. | |
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