Impact of seed cold stratification on apricot germination and subsequent seedling growth as well as chemical constituents of seeds during stratification

Freshly harvested seeds of apricot varieties "Balady (Amar)" and "Hamawy" were found to be dormant and did not germinate at all. A specific low-temperature stratification treatment was required to overcome seed dormancy. 5°C cold stratification was found to be the best for breaking seed dormancy, germination and seedling growth. Increased seed germination percentage was recorded when the period of stratification prolonged. Seedling developed from stratified seeds had better growth than those developed from non-stratified seeds. Apricot seeds required a cold stratification of about 12-15 days for "Balady variety (Amar)" and15-18 days for "Hamawy" variety "to reach maximum germination and normal seedling growth. Chemical constituents of apricot seeds (total and reducing sugars, total free amino acids and total indoles were increased while that of free phenols and total soluble phenols were decreased) when stratification period prolonged. Therefore, it can be suggested that breaking of dormancy is coincided with several changes in different chemical constituents of seeds. Some of these materials increased and other materials which decreased at seed germinations.