Extended abstract
Introduction: Growth, development, and ultimately production of plants are affected by several environmental factors. Drought and salinity are major environmental stresses that have irreparable effects on all stages of germination, plant growth, and the structure and activity of organs. The germination stage and seedling establishment are more sensitive to osmotic and salinity stresses, so it is important to evaluate the germination indices under stress conditions for plant cultivation in dry and saline environments.
Materials and Methods: To investigate the effect of different levels of osmotic and salinity on germination and early growth of camelina (Camelina sativa L.), two experiments were conducted separately in a completely randomized design in the laboratory of Bardsir Faculty of Agriculture, Shahid Bahonar University of Kerman in 2023. In the first experiment, polyethylene glycol solution (PEG 6000) at -0.2, -0.4, and -0.6 MPa levels was applied to generate the osmotic potential. In the second experiment, NaCl at 50, 100, and 150 mM concentrations was used. In both experiments, distilled water was used to create zero stress (control).
Results: The results showed that mild osmotic (-0.2 MPa) and salinity (50 mM) stresses had no significant adverse effect on seedling establishment. However, increased intensity of osmotic and salinity stresses significantly reduced germination percentage and rate, seedling vigor length index, seedling dry weight, radicle length and dry weight, and plumule length and dry weight, so that drought stress at -0.6 MPa reduced the length and dry weight of the root and the length and dry weight of the plumule by approximately 40.40%, 57.4%, 49.2%, and 53.3% compared with the control, respectively. The highest level of salinity stress (150 mM) caused a decrease of 37.8%, 56.8%, 45.3%, and 55.4% in the length and dry weight of the root and the length and dry weight of the plumule compared with the control, respectively. An increment of MDA content, soluble carbohydrates, and the amount of free amino acids was observed at moderate (-0.4 MPa) and severe (-0.6 MPa) osmotic stress and 100 and 150 mM salinity stress levels.
Conclusions: Since camelina is a new plant in Iran, evaluating the response of this plant to different levels of osmotic and salinity stress during germination and early growth stages of the seedling provides the possibility of its cultivation and development in the dry lands of different regions of the country. It seems that mild drought (-0.2 MPa) and salinity (50 mM) stresses did not have a significant adverse effect on camelina germination indicators, but if the stress level exceeds the plant's tolerance range, it leads to decreased germination traits. Recommending the cultivation of this species requires studying its stability, compatibility, and agroecological characteristics.
Highlights:
- Germination characteristics and initial growth of camelina seedlings were investigated under drought and salinity stress conditions.
- The tolerance threshold of camelina seedlings was evaluated to different water potentials and salinity stress.
- The sensitivity of germination components to salinity stress was higher than that of osmotic stress.
