Alternating temperatures increase germination and emergence in relation to endogenous hormones and enzyme activities in aubergine seeds

• Published in: South African journal of botany 2021-07, Vol.139, p.130-139
• Main Authors: Ozden, Eren, Light, Marnie E., Demir, Ibrahim
• Format: Article
• Language: English
• Subjects: Abscisic acid; Antioxidant enzymes; Auxins; Fluctuating temperatures; Lipase; Seed dormancy; Solanum melongena
• ISSN: 0254-6299; 1727-9321
• DOI: 10.1016/j.sajb.2021.02.015

•Alternating temperature enhanced seed germination in four cultivars of aubergine.•The most effective treatment tested was a temperature regime of 35/20°C at 16/8 h.•Endogenous hormone analysis showed decreased ABA in seeds with higher germination.•Increased germination and emergence correlated well with increase lipase levels.•There was a corresponding increase observed in SOD with increased germination. High seed quality is important for obtaining high quality seedlings for commercial vegetable production. The rate of seed germination affects seedling quality since seeds which tend to germinate more slowly generally result in low-quality seedlings, especially in aubergine seeds. Alternating temperatures play a crucial role in determining the rate of seed germination in many plant species. This study investigated the effect of alternating temperatures on aubergine seed germination, emergence rates, and physiological changes regulating dormancy. Seeds from four open-pollinated aubergine cultivars were incubated for 14 days under the following temperature regimes: 35/20°C-24/24h, 35/20°C-16/8h, 35/20°C-8/16h, 30/20°C-24/24h, 30/20°C-16/8h, 30/20°C-8/16h, or at constant 25°C. The highest mean germination was 92%, with a corresponding highest mean emergence of 88%, which was found with the 35/20°C-16/8h treatment. All alternating temperature treatments displayed faster germination and emergence compared to the control (25°C), as well as high catalase, superoxide dismutase and ascorbate peroxidase antioxidant enzyme activities, and high auxin and salicylic acid levels. In contrast, lipase enzyme activity, abscisic acid and jasmonic acid content decreased. In conclusion, these findings showed that alternating temperatures improved aubergine seed germination rate, and seedling emergence, and also demonstrated positive correlations with enzymatic and hormonal fluctuations within the seeds.