Effects of pH of a nutrient medium on parameters of growth and rhizogenesis of wild-type blue honeysuckle (Lonicera edulis (Turcz. ex Herder) Turcz. ex Freyn) in in vitro culture

Under natural conditions, species of blue honeysuckles grow on soils with a wide range of pH. In this work, for the first time under artificial in vitro conditions, the influence of nutrient medium pH of 3.8 to 8.3 on the viability and growth and development parameters was studied in a species Lonicera edulis from the bluehoneysuckle subsection. It was found that nutrient medium pH does not affect the propagation coefficient of Lonicera edulis; however, more alkaline media caused shortening of its shoots by reducing the length of internodes. Our data suggested that pH affects the rooting of in vitro microshoots of the species under study. Two optima for the rhizogenesis were found: pH 3.8–4.3 (56.5–60.1 % rooting capacity) and pH 6.3–6.8 (53.8–61.1 %). Meanwhile, the height of the shoots and the number of leaves at the rooting stage did not significantly differ among pH values of the medium. Thus, these in vitro culture experiments confirm the tolerance of Lonicera edulis to a wide pH range.