Optimization of in Vitro Cultivation Conditions of Blood Hawthorn (Crataegus atrosanguinea)

Extended Abstract Background: It is important to research in the field of germplasm protection of native and medicinal tree species in northern Iran forests, especially blood hawthorn with many medicinal properties. Sexual reproduction of hawthorn is possible with apomixis due to the thick shell and two types of physical and physiological dormancy, and its asexual reproduction by rooting cuttings faces many problems. Bloody hawthorn (Crataegus atrosanguinea from the Rosaceae family) is considered one of the valuable species of the forests of the north and west of the country, which is very important due to its fruitfulness, very strong wood, and numerous medicinal properties. The medicinal properties of hawthorn have been proven in the treatment of blood pressure, arteriosclerosis, heart congestion, heart muscle weakness, and coronary insufficiency. Hawthorn contains many secondary metabolites such as flavonoids proanthocyanidin and glycosides. Optimizing the in vitro cultivation conditions of blood hawthorn as one of the natural species of Iran can be a suitable solution for its propagation. The present research was carried out to control pollution, control browning, and induce the callus of blood hawthorn (C. atrosanguinea) in vitro. Controlling the contamination of explants, seeds, and plant tissues is of great importance for the success of plant tissue culture. Since the enrichment of natural plant explants is a priority for tissue culture, this is usually associated with many problems with browning, especially for woody plants that have a thick and woody stem. Determining the type and concentration of the growth regulator of a variable factor is necessary for the growth of plants under in vitro conditions. After applying the growth regulator to the culture medium, the plant will show different reactions, but one of the appropriate ways to choose the correct path of plant regeneration is to determine the wet and dry weights of the callus, which is widely measured as a standard of callus growth. The callus growth curve can be obtained using the wet and dry weights of the callus. The results of past research indicate a wide range of changes in the type and concentration of growth regulators on callus formation and regeneration of different species of the hawthorn genus. A specific type and concentration of growth regulators should be applied according to the type of plant species. Methods: Young and healthy stems of blood hawthorn were collected from Lar