Physiological Ecology of ceratonia siliqua at Al-gabal Al-akhdar area

Abstract

Carob tree (Ceratonia siliqua L.) is environmentally and economically important tree and is among the most difficult to propagate fruit and slow-growing an species. It is an evergreen endemic wild species found naturally in El-Jabal El-Akhdar region which is located immediately south of the coastal belt in the northeastern region of Libya. Aim and methodology: The first part of the study was to examine the morphological characteristics of carob tress in 4 different locations in El-Jabal El-Akhdar region (Albyadah, Tukrah, Wadi El-Kouf and Al Himadah), five characters on discriminative pods measured to know (pod size, number of seeds per pod, weight of 100 seeds, seeds size, leaf size) , another two characters measured directly in the study location which are stem diameter and whole tree height, The second part of the study was to examine the effect of different pre-sowing treatments found in previous literature on the growth of carob seeds, which are (boiling water, tab water, mechanical scarification and sulfuric acid). Germination percentage, mean germination time, seedling viogros index and seedling development individually evaluated and compared with control for each pretreatment, procedures performed according to a fully developed protocol of in vitro seed germination for carob found in previous literature. Results: For the morphological characters study generally no significant morphological differences found among theses population except in leaf size which was highly significant, Tukhra area showed smaller leaf size compared with other locations. No significant correlations between pod size and other morphological characters of carob in all locations except in Albyadah in which a significant negative correlation was found between pods sizes and seeds sizes. Compared to control, generally all pretreatments significantly enhanced the germination of carob seeds, relatively higher germination percentage was noticed in the seeds soaked in boiling water 96%, followed by carob seeds treated with sulfuric acid for 15 minutes which showed 60% germination, the mechanical scarification and sulfuric acid for 10 minutes showed germination percentages 40%, the seeds treated with sulfuric acid for 5 minutes showed relatively the germination percentage 32%, while the treatment with regular tap water showed zero germination. Faster germination was recorded by seeds pre-treated with sulfuric acid for 15 minutes, followed by germination recorded by carob seeds pre-treated with boiling water, then seeds pre-treated with sulfuric acid 10 minute, seeds pre-treated with sulfuric acid 5 minutes and mechanical scarification showed somewhat delay in germination. Carob seeds pretreated with soaking in boiling water showed significant differences in their fresh weight, root and shoot lengths compared with untreated control seeds, while results of dry weight was not significant compared to control treatment.