Optimization of Sterilization and Micropropagation of Water Lettuce (Pistia stratiotes L.)

Abstract

Water lettuce (Pistia stratiotes) is an important medicinal aquatic plant that is also used for phytoremediation or as bioindicator. It is very difficult to multiply the plant using micropropagation techniques due to high contaminations. The study aimed to alleviate this problem for efficient multiplication of the plant subsequently. The study made use of 60% commercial bleach (5% NaOCl) or 60% H2O2 for surface sterilization for 10 min followed by adding 500 mg/l Duocid® (a wide spectrum antibiotic) in the culture medium. The results showed that
commercial bleach was not proper sterliser as all explants bleached; whereas, 60% H2O2 based surface sterilization was most optimum for the purpose. The Surface sterilized plants were in vitro cultured on agar solidified or liquid MS medium containing 0.05-0.40 mg/l kinetin. Cent
percent shoot regeneration frequency was on both agar solidified or liquid medium. However, all explants on agar solidified or liquid medium had tenancy to die turning all of them to albino. Therefore, multiplication under ex vitro conditions on liquid MS medium containing
0.05-0.40 mg/l kinetin or BAP using unsterilized shoot meristems without adding sucrose. Subsequently, the explants induced 2.0-40 plantlets per explant on 2.0-3.0 mg/l kinetin or BAP containing culture medium. The plants regenerated on both culture media were
comparable with plants growing under natural conditions and did not show any sign of stress causing albinism or necrosis.