NEGATIVE PRESSURE IN THE APOPLAST OF ELONGATING TISSUE INDUCES WATER UPTAKE FOR CELL ELONGATION IN TISSUE-CULTURED PLANTS

This work was undertaken to investigate to what extent water uptake capacity could regulate cell expansion rates of plants subjected to environmental stresses under tissue-culture conditions.
Embryos isolated from soybean (Glycine max L. Merr.) and kidney bean (Phaseolus vulgaris L.) seeds, and shoot meristems of carnation plants (Dianthus vulgaris L.) were grown under tissue-culture conditions.
Water potential of culture media ranged from -0.02 to -0.94 MPa so that nutrient deficiency and salt stress conditions could be applied to plants grown in the media.
Additionally, the temperature of culture conditions was set from 10 to 40 °C to apply low temperature and high temperature stresses on plants grown at the optimum concentration of culture medium.
Cell expansion could be inhibited completely by adding auxin and cytokinine to culture media to form callus tissue.
Sizes of the water potential gradient between the water source and elongating cells were linearly correlated with growth rates under nutrient deficiency, salt stress, changes in morphogenesis, low temperature and high temperature conditions in all plant species used in the present study, indicating that cell expansion rates were regulated by how much water could be absorbed by elongating cells regardless of kinds of given environmental stress conditions.
The driving force for water uptake in elongating cells was the negative pressure in the apoplast in the elongating tissue.

International Symposium on Plant Production in Closed Ecosystems

H. Nonami, Y. Hashimoto

cell elongation, growth-induced water potential, negative pressure, osmotic stress, salt stress, tissue culture

https://doi.org/10.17660/ActaHortic.1996.440.104