Abstract
Concentrations of nutrient solution can be expressed in terms of water potential instead of electric conductivity (EC), which is used conventionally in management of nutrient solution concentration in plant growth factories. Water potential is a convenient concept to use when expressing directions of water flow in plants, and therefore, may be useful in the regulation of growth of plants cultivated in plant growth factories. In the present study, Phaseolus vulgaris seedlings were used to study relations between growth and water status when concentrations of nutrient solution were changed. Growth inhibition under high concentrations of the nutrient solution was not related to turgor in the elongating region, but was co-related with the magnitude of the growth-induced water potential, which was estimated from the difference between water potentials of the mature region and the elongating region. Because the growth-induced water potential determined cell expansion, it can be safely stated that growth of plants in plant growth factories can be regulated if the growth-induced water potential can be measured, although simple measurement methods for growth-induced water potential have not yet been developed.
