PHENOLOGICAL AND PHYSIOLOGICAL-STUDIES DURING CAROB (CERATONIA-SILIQUA L) SEED-GERMINATION

The best pre-sowing treatments for carob (Ceratonia siliqua L.) seeds germination were acid scarification or treatment with warm water (40 d egrees C) for 48 h. Different phenological phases were characterized e ssentially based on morphological events during carob germination. Cha nges in total protein, free animo acid content and ethylene production were also studied and used for physiological characterization of phen ological events. The fresh and dry weight of seedlings showed a steady increase, after the emergence of the radicle. At this point ethylene production attained the highest level. Dry weight of seedlings and cot yledons increase was accompanied by a decrease of endosperm reserves u ntil they reached a plateau by the eighth day. Both protein and amino acid content of cotyledons increased with germination up to 6 days and then decreased. That increase was related to the onset of germination and hook development. It remained almost unchanged on subsequent days but between the 12th and the 14 h the protein and amino acid content of cotyledons slowly started to increase. Embryonic axis amino acid co ntent followed the same pattern but protein content only showed small variations throughout the experimental period. The presence of cotyled ons as a source of necessary products for the development of the embry onic axis is discussed.