Peculiarities of the sterilization of Hydrangea L. explants during introduction into in vitro culture
DOI:
https://doi.org/10.31210/spi2026.29.02.02Keywords:
hydrangea, microshoots, viability, sterilizing agent, exposureAbstract
This article examines the effectiveness of sterilizing agents and sterilization methods for Hydrangea explants during their introduction into in vitro culture. The starting material for in vitro culture consisted of microshoots with apical meristems excised from 3- to 5-year-old plants of H. macrophylla 'Nikko Blue', H. arborescens 'Annabelle', and H. paniculata 'Grandiflora'. It was established that the most effective sterilizing agent was a 0.1 % solution of mercuric chloride (HgCl₂). Its application with an exposure time of 1–1.5 min resulted in 67.2–85.5 % sterile microshoots, of which 62.8–73.3 % were viable. Increasing the exposure time to 2.0 min led to a decrease in explant viability to 54.7 %. The least effective sterilizing agent was 2.5 % sodium hypochlorite (NaOCl), which resulted in up to 55.8 % sterile explants across all exposure times. Treatment with a 1.0 % silver nitrate (AgNO₃) solution yielded a higher proportion of sterile explants compared to sodium hypochlorite; however, their viability was the lowest among all treatments. After 2 min of exposure, the proportion of sterile explants reached 72.8 %, but only 20.5 % remained viable. It was also found that explants of all studied species and cultivars of the genus Hydrangea, collected and introduced into in vitro culture in May, showed lower contamination levels; however, the proportion of sterile viable explants was significantly lower (19.4–20.6 %) compared to those collected and introduced into culture in July. It was determined that the highest yield of viable sterile explants was obtained when they were introduced into in vitro culture during July 5–25, with average values of 65,1–67,2 % for the studied species and cultivars of hydrangea, respectively. The lowest percentage of viable explants was observed when explants were introduced into culture on May 5, ranging from 17.9 % to 20.6 %. Meristem development, as well as the expression or suppression of totipotency, depended on the conditions under which the explants were introduced into in vitro culture. The best results were achieved by culturing sterilized plant material on a nutrient medium at an air temperature of 25±1°C, with a 16-hour photoperiod, a light intensity of 1–3 klx, and a relative humidity of 75 %.
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