Abstract:
Osmotic stress is the main problems in aquatic plant as this stress decreasing water
content, inhibiting the rate of photosynthesis, decreasing the rate of respiration,
decreasing the protein synthesis or increasing protein hydrolysis and also increasing
the accumulation of sugars. In this study, the responses of Cryptocoryne elliptica to
drought stress were investigated in vitro. The plantlets were cultured in Gamborg B5
media added with osmotic stress agent, mannitol at different concentrations (0, 20 and
40 mM). The changes in plant growth, total chlorophyll, soluble protein and reducing
sugar content were measured at every 5 day intervals for 30 days. The drought stress
restricted significantly the growth and development of C. elliptica cultures. The
biomass of control plants increased progressively during the 30 days treatment, in
contrast to that both mannitol-stressed plants which decreased. The drought stress
decreased significantly the total chlorophyll and soluble protein content after 10 days
of treatment. At the final harvest, total chlorophyll and soluble protein content was
higher in control plants than stressed plants. Drought treatments cause the
accumulation of reducing sugar. The high reducing sugar content was observed in
plants treated with 40 mM mannitol. The effect of drought stress on plants increasing
as the mannitol concentration increased. Drought stress affects the physiology and
biochemical activity of C. elliptica cultures.