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 assay the effect of different concentrations of osmotic and salinity on germination and early growth of camelina (Camelina sativa), two experiments were performed 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 (PEG6000) with concentrations of -0.2, -0.4, and -0.6 MPa was applied to acquire the osmotic potential. In the second experiment, NaCl with concentrations of 50, 100, and 150 mM was used. Both experiments also applied distilled water to make zero stress (control).
Results: The results showed that mild osmotic stress (-0.2 MPa) and salinity (50 mM) had no significant adverse effect on seedling establishment, but increasing the intensity of osmotic and salinity stresses significantly reduced germination percentage and rate, seedling vigor length index, seedling dry weight, radicle length and dry weight, plumule length, and dry weight. So, drought stress of -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% respectively compared to the control. 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 respectively, compared with the control. An increment of MDA content, soluble carbohydrates, and the amount of free amino acids was observed in moderate (-0.4 MPa) and severe (-0.6 MPa) osmotic stress and 100- and 150-mM salinity stress.
Conclusions: Since Camelina is a new plant in Iran, evaluating the response of this plant to different levels of osmotic and salinity stress in the 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 stress (-0.2 MPa) and salinity (50 mM) stress did not have a significant adverse effect on Camelina germination indicators, but if the stress level exceeds the plant's tolerance range, it led to decreased germination traits. In fact, recommending the cultivation of this species requires studying its stability, compatibility, and agroecological characteristics.
Highlights:
- Cultivation and extension of camellia need basic research at first regarding the investigation of germination characteristics and initial growth of seedlings under drought and salinity stress conditions.
- Evaluation of the tolerance threshold of camellia seedlings to different water potentials and salinity stress.
- The sensitivity of germination components to salinity stress was higher than osmotic stress.
