Document Type : Research Paper
Authors
1
Department of Plant Production Engineering and Genetics, Campus of Agriculture and Natural Resources, Faculty of agriculture, Razi University. Kermanshah, Iran.
2
Greenhouse and Controlled Environments Research Center, Department of Post Harvest Physiology and Technology, Horicultural Sceinces Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran.
3
Faculty of Engineering, Department of Agricultural Sciences, Payame Noor University, Tehran, Iran.
Abstract
Brassinosteroids are steroid hormones that are essential for the growth and development of plants and play a significant role in plant responses to stress. This study delves into examining how 24-epibrassinolide influences seedling indices, physiological and biochemical traits in specific lettuce genotypes under drought stress. The factorial experiment was conducted using a completely randomized statistical design with four replicates at the research laboratory of plant physiology, Faculty of Agriculture, Agriculture and Natural Resources Campus, Razi University, Kermanshah, Iran in 2023. The experiment included two selected lettuce genotypes, namely Icy and Romance, as the first factor. The second factor comprised seed pretreatment at four levels of priming with 24-epibrassinolide (0, 50, 100, and 150 μM), while the third factor consisted of drought stress at four levels (0%, 10%, 20%, and 30%) induced by mannitol. The assessed traits encompassed germination rate, root length, stem length, Relative Water Content (RWC), total sugar content, total phenol content, and flavonoid content. Comparative analysis of average traits revealed that the levels of biochemical traits, specifically total sugar (0.480 mg/l), phenol (460.83 mg/l), and flavonoid (1.047 μg/l), escalated with higher levels of drought stress. Principal component analysis indicated that the first two components elucidated 64% of the variations. The findings suggest that priming with 150μM of 24-epibrassinolide hormone is advisable to attain the highest seedling indices in lettuce. According to the results obtained in this research, the Roman line is introduced as the best line in drought stress conditions.
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