Nucellar embryony and formation mechanism in important citrus rootstock

In this study, mechanism of nucellar embryony is aimed to determine in some important Citrus rootstocks. In this study, Carrizo citrange, Cleopatra mandarin, Volkameriana and Sour orange were used as mother plant and Poncirus trifoliata var. Yerli as pollenizer. With cytological and histological studies on rootstocks; the formation periods, formation places, nutrient supply and to what extent these situations can be change in terms of rootstocks was studied. As a result of the study, it was determined that formation and development of nucellar embryo initial cells (NEICs) were differed between rootstocks. In this context, the NEICs were formed from chalazal or micropilar parts of the nucellus differing between rootstocks. In terms of formation periods, while the NEICs were formed at 5th day after pollination regardless of pollination in Cleopatra mandarin, in Volkameriana they formed before fertilization depending on pollen stimulation. However, in Carrizo citrange and Sour orange, the NEICs were formed after fertilization depending on pollinaton. Nutrient supply features of NEIC were similar for all used rootstocks. These cells were used nucellus tissue for their first development and after reaching to embryo sac, they start to use up the endosperm to form an embryo.