Phytotoxicity of introduced Pinus halepensis Miller trees on physiological responses of native Ceratonia silique L. trees in the Green Mountain area, Libya

Abstract

This research was conducted at Department of Botany, Faculty of Sciences, University of Benghazi in Libya, to examine the phytotoxicity of introduced P. halepensis (Aleppo pine) trees on some physiological measures of native C. siliqua (Carob) trees in wadi Alkhoof area at AL-Jabel AL-Akhdar in Libya. Therefore, lab experiments were performed using aqueous extracts of the needles and the bark of P. halepensis and the soil rhizosphere around it with different distances (0.0, 2.0, and 4.0) with two depths (10 and 20 cm) of each soil type. Needles, bark, and soil rhizosphere were seasonally collected. Needles and bark were collected in the middle of each season (autumn, winter, spring, and summer. Based on the results of needles and bark extracts, it has been decided to use the above mentioned soil types which collected in winter and summer seasons. Different concentrations (0.0, 25, 50, 75, and 100 g / l) were prepared from the extract of each plant organ (needles and bark) and from each soil type, to evaluate their effects on seed germination and early seedling development of C. siliqua. Some parameters were carried out for seed germination and for seedling development. For seed germination tests, daily germination percentages,