Development of a medium and culture system for in vitro propagation of the seagrass Halophila engelmannii

Abstract

An in vitro culture system was developed for axenic culture of the seagrass Halophila engelmannii Aschers. The culture system had a rhizome layer solidified with agar (0.8% w/v) and a liquid overlay layer. The rhizome layer contained artificial seawater (20%0, inorganic nutrients, plant growth regulators, sucrose (1% w/v), and activated charcoal (1% w/v). The overlay layer contained artificial seawater and inorganic nutrients. The medium f/4 provided the best source of inorganic nutrients of the five media compared. Axenic cultures of H. engelmannii died if NO3 was the only N source. They grew best when supplied with glutamic acid at a concentration of 3.4 mM as the N source. A combination of α-naphthaleneacetic acid at a concentration of 0.25 mg ∙ L−1 and 6-benzylaminopurine at a concentration of 10 mg ∙ L−1 provided the most rapid rates of propagation as measured by the numbers of pseudowhorls and branches produced. Key words: tissue culture, marine plants, media, plant growth regulators.