Germination Responses and Phenolic Compounds of Securiger securidaca L. Seeds under Drought and Salinity Stress Conditions

Abstract

Abiotic stresses affect the germination of many plants. To evaluate the tolerance of the Securiger securidaca medicinal plant to salinity and drought stress in the germination stage, two experiments with a completely randomized design with three replications were conducted in the Seed Science and Technology Laboratory of Shahed University. In this experiment, drought stress includes osmotic potentials of zero (control), -0.2, -0.4, and -0.8, and -1.2, -1.4, -1.6, and -2 MPa, which were prepared from polyethylene glycol 6000, and salt stress was applied using sodium chloride (NaCl) at levels of zero, 2, 6, 10, and 14 dS/m. The results showed that drought stress caused a significant decrease in the germination percentage and rate, shoot and root length, and seedling length, and increased total phenol content. With the increase in drought stress levels to -2 MPa, the percentage of germination decreased by 38.86% compared to the control, and the significant decrease in the percentage of germination started at the level of -0.2 MPa. Salinity stress also affected the germination percentage and rate, root and shoot length, seedling length, and phenol content. Increasing phenol content started at the level of drought stress (-1.2 MPa) and salinity stress (6 dS/m) and intensified with the increase in stress. The results of the research showed that increasing the levels of salinity stress up to 14 dS/m and drought stress up to 2 MPa has a significant decrease in the seed germination percentage of S. securidaca, which can be problematic in the establishment of seedlings.

Keywords

• germination rate: osmotic potential
• phenol
• polyethylene glycol
• sodium chloride