Effects of Temperature and Light on the Germination-Promoting Activity by Melatonin in Almond Seeds without Stratification

Abstract

Melatonin is a new plant hormone involved in multiple physiological functions in plants. Its roles in germination, photosynthesis, growth, flowering, fruiting, and senescence are noteworthy. Most studies have focused on its protective role in different stress situations, both biotic and abiotic. Preliminary data on its promoting role in almond seed germination and seedling growth are presented in this work. The germination-promoting capacity of melatonin was studied in different conditions of light and temperature, with important differences with respect to untreated seeds. The data confirmed that, at specific concentrations, melatonin was capable of stimulating germination, avoiding the stratification process, and therefore, shortening germination times. Furthermore, the melatonin-primed seedlings showed a higher root and aerial growth versus the untreated seeds when light was applied. The possible agronomic impact on the propagation of stone fruit trees was also discussed.