Optimization of Seed Surface Sterilization Method and <i>in vitro</i> Seed Germination in <i>Althaea officinalis</i> (L.) - An Important Medicinal Herb

Abstract

Objectives: The species Althaea officinalis is belong to Malvaceae family; its common name is Marshmallow. In this study an efficient technique has been optimized for sterilization of seed surface and also in vitro germination of seeds. Methods: Effect of different sterilizing agents with various concentrations and duration times as well as different media with various concentrations of sucrose on MGT (mean of germination time), GP (germination percentage), GR (germination rate), NDFG (number of days to first germination), CP (contamination percentage) and length of root and shoot of seedlings were recorded. For each experiment 25 seeds were treated and it was repeated at least three times. Findings: The maximum GP (80.0%) was recorded in sterilized-distilled water for 20 min (control), whereas minimum GP (44.0%) was recorded in experiment using 0.3% mercuric chloride (HgCl2) for 7 min. Between seed surface sterilization techniques used, maximum CP was achieved in control (85.33%) and minimum was found in 4% NaOCl (Sodium Hypochlorite), 10 min (13.33%), 0.3% HgCl2 for 7 min (14.66%) and 4% NaOCl for 5 min (17.33%). We compared the measured seed germination values (NDFG, MGT, GR, GP and CP) and among seed surface sterilization methods tested, NaOCl, 5 min has been found to be the best in A. officinalis. In addition, presence of sucrose in germination medium has shown negative effect on seed germination measured values as well seedling development. The effect of different surface sterilization techniques have no significant effect (p ≤ 0.05) on number of days to first germination (NDFG) but these techniques significantly affected (p ≤ 0.05) the other characteristics of seed sterilization. According to ANOVA results we report for the first time the best sterilization method and medium for in vitro seed germination and seedling development in A. officinalis.