Extended Abstract
Introduction: Various strategies have been used to improve growth and productivity of crops through genetic approach, genetic engineering, and breeding. However, economic feasibility and ease of use can pave the way for the application of priming techniques as "stress relievers" in agricultural production. The aim of this study was to evaluate the ability of priming Catharanthus roseus seed with phytohormones of salicylic acid and Jasmonic acid under drought stress to reduce the effect of water limitation during the germination.
Materials and Methods: Two separate studies were conducted as a factorial experiment based on a completely randomized design with three replications at the Laboratory of Seed Science and Technology of Shahed University, Tehran. In the first experiment, treatments included priming in two levels of SA (0.5 and 1mM) and priming duration in two levels (24 and 48 hours), and drought stress with polyethylene glycol 6000 in 6 levels (0, 0.1, 0.5, 1, 1.5 and 2 Mpa). In the second experiment, treatments included JA (10 µM), priming duration in two levels (12, and 24 hours) and drought stress in levels six (0, 0.1, 0.5, 1, 1.5, and 2 Mpa). Dry seeds (without pretreatment) were considered as control.
Results: In this study, drought stress treatments -1.5 and -2 Mpa in the first experiment and -1, -1.5 and -2 Mpa in the second one had no germination. Seed priming with SA and JA improved the percentage of seed germination so that in the first experiment, the highest percentage of germination (97.33) was observed under stress-free conditions with the application of 0.5 mM salicylic acid for 48 hours, which was 12.2% higher than the control treatment. 0.5 Mm of SA treatment with 24 hours of priming showed the highest percentage of germination under drought stresses of -0.1 and -0.5 Mpa. However, under drought stress conditions of -1 Mpa, 0.5 mM SA+48 hours treatment was superior compared to other treatments of salicylic acid and time. In the second experiment, the highest percentage of germination (98.3) was in the concentration of 10 μM jasmonic acid during 24 hours of priming under stress-free conditions, which showed an increase of 40.4% compared to the control treatment.
Conclusion: The results of the present study showed the importance of salicylic acid and jasmonic acid during seed germination stage under drought stress. Seed priming with salicylic acid alleviated the damages caused by drought stress on germination and growth. The process of adaptation to stress started by jasmonic acid can be attributed to pretreatment with jasmonic acid before applying drought stress.
Highlights:
- The effect of priming Catharanthus roseus seeds with salicylic acid and jasmonic acid phytohormones on the germination characteristics of seeds under drought stress was investigated.
- Priming Catharanthus roseus seeds with salicylic acid improved the germination percentage and characteristics of seeds under drought stress.