The objective of this study was to simultaneously determine changes in tryptophan and melatonin contents of eggplant seedlings at two different growth stages during a 24-h period. | Turkish Journal of Botany Turk J Bot (2017) 41: 356-366 © TÜBİTAK doi: Research Article Determining diurnal and seasonal changes in melatonin and tryptophan contents of eggplant (Solanum melongena L.) 1, 2 1 3 4 Ahmet KORKMAZ *, Gökçen YAKUPOĞLU , Şebnem KÖKLÜ , Yakup CUCİ , Ferit KOCAÇINAR 1 Department of Horticulture, Kahramanmaraş Sütçü Imam University, Kahramanmaraş, Turkey 2 Andırın Vocational School, Kahramanmaraş Sütçü Imam University, Andırın, Kahramanmaraş, Turkey 3 Department of Environmental Engineering, Kahramanmaraş Sütçü Imam University, Kahramanmaraş, Turkey 4 Department of Forest Engineering, Kahramanmaraş Sütçü Imam University, Kahramanmaraş, Turkey Received: Accepted/Published Online: Final Version: Abstract: The objective of this study was to simultaneously determine changes in tryptophan and melatonin contents of eggplant seedlings at two different growth stages during a 24-h period. Variations in tryptophan and melatonin levels in different organs (roots, leaves, fruits, and seeds) and the distribution and accumulation of these molecules in these organs during various growth stages were also investigated. In eggplant seedlings, melatonin showed a strong peak at the beginning of the dark period, while tryptophan levels were at the lowest. Melatonin was also high in the middle of the light period and an inverse relationship was observed between melatonin and tryptophan levels. These results indicated that melatonin fluctuations in eggplant seedlings are likely the result of the combined effects of endogenous and environmental factors. Melatonin was found in high quantities in seedlings and mature seeds, and its concentration in leaves and roots decreased dramatically as the growth stages progressed. On the other hand, tryptophan content in leaves and roots increased markedly as the growth season progressed, and the highest tryptophan levels were
