The effects of salt stress and prime on germination improvement and seedling growth of Calotropis procera L. seeds

Calotropis procera L. is a perennial shrub distributed in saline areas of deserts of South Asia. Salt stress is a very challengingsubject in arid and semi-arid areas. Germination stage is very sensitive and many plants do not germinate insaline soil. The objective of this study was identifying the salinity effect on seed germination of Calotropis procera L. Theexperimental design was a complete randomized block design with NaCl and CaCl2 at five levels of isobar concentrations:0.0, -0.01, -0.05, -0.1, and -0.15 MPa. Osmotic potential had significant effects (P < 0.01) on germination percentage,germination rate, shoot length, root length, and seedling dry weight. All seedling characteristics decreased with decreasein osmotic potential. Shoot length and root length decreased more than the seedling characteristics. Germination wascompletely inhibited in -0.1 Mpa. Priming with NaCl and CaCl2 (-0.1 MPa) for four days had significant effects (P < 0.01)on the germination percentages. Priming improved the seedling characteristics in all samples, especially in -0.05 Mpa,but a decrease with decrease in osmotic potential.