Salt tolerance of Giant reed (Arundo donax L.) ecotypes in callus cultures in vitro

Abstract

Nowadays, soil salinity is a big challenge for agronomists and plant growers due to irrigation in arid lands where the respiration rate is very high and in coastal areas saline water floods the soil. Salinity is caused by the accumulation of soluble salts in the root zone. Excess salts reduce the productivity of plants like growing potential, vigor and seed germination, due to the altered water and mineral uptake. Among salts the amount of sodium and chloride ions is very critical because most of the plants are sensitive to them. Arundo donax L., commonly known as giant reed, has a wide habitat range thus it has wide tolerance to soil conditions. Hence, it may has high resistance to salinity and sodicity, too. It is a typical plant of freshwater ecosystems. Although A. donax is widespread all over the world, it has only slight genetic differences between ecotypes due to its vegetative propagation strategy. A. donax can be propagated by in vitro tissue culture technique. In vitro cell culture is suitable for large scale selection of cells where cells are exposed to stressors such as high salinity or sodium. This form of selection can reduce the time and space requirements, reducing the need for conventional selection in open filed experiments. In our experiment 12 ecotypes of A. donax were tested in in vitro callus cultures. Callus cultures were exposed to salt stress by adding five different concentrations of sodium chloride (NaCl) to the culture medium. Growth parameters of callus cultures were measured by the fresh and dry matter production, under constant laboratory conditions. The fresh weight of calli decreased while their dry weight increased with increasing NaCl level in culture medium. According to our experiments, differences in NaCl tolerance were registered between the different ecotypes.