In vitro Seed Germination of Coscinium fenestratum (Gaertn.) Colebr

Abstract

The present investigation was aimed to study the In vitro seed germination potential of Coscinium fenestratum - An endangered woody climber with high medicinal value to ensure germplasm conservation and mass production of planting material to meet the unlimited demand. Mature seeds of C. fenestratum can be successfully surface sterilized by dipping explants in 0.1% Mercuric Chloride (HgCl2) solution (w/v) for 2 min followed by 2 successive washings using sterilized distilled water. After surface sterilization, hard seed coats have to be damaged to overcome mechanical seed dormancy. After that seeds should be soaked 24h in filter sterilized 2,250 mg/L Gibberelic Acid (GA3) solution to break the physiological dormancy. When mature seeds stored at 4ºC for 3- 6 months, in sealed cellophane after wrapping with wet cotton; soften the hard seed coats make it easy for mechanical damaging. The experiments were repeated in two fruiting seasons (September 2011 and June 2012). Seeds have to be cultured into MS salt fortified sterilized sand: coir dust (1:1) incorporated culture vessels. To minimize fungal contaminations; 0.7g/L systemic fungicide - Thiophanate methyl 70% WP (w/v) has to be introduced into culture medium. To facilitate in vitro germination, seeds should be exposed to total darkness and temperature should be increased to 32±2 0C inside an incubator. Fresh seeds treated with 2,250mg/L GA3 for 24 h before culture initiation achieved 80% mean In vitro germination rate within 9 months of culture period. After 3 months of storage, to achieve 76% mean In vitro germination rate within a month seeds need to be exposed 24 hour to 2,250mg/L GA3. If they soaked 24h in sterilized distilled water, it was needed 4 months time to gain same result. Over 90% seedlings were successfully acclimatized and introduced to field conditions.