Inhibition of the growth of micro-algae and bacteria by extracts of eelgrass (Zostera marina) leaves

✍ Scribed by Paul G. Harrison; A. T. Chan

• Publisher: Springer-Verlag
• Year: 1980
• Tongue: English
• Weight: 594 KB
• Volume: 61
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00410338

✦ Synopsis

The effects of the water-soluble fraction of dead leaves of the eelgrass Zostera marina L. on the growth of 8 species of micro-algae (pennate and centric diatoms, dinoflagellates, and a green flagellate) and a bacterium were studied on agar plates and in liquid culture. The extracts of leaves which had been dead from a few days to 2 wk inhibited growth and often killed cells in all test organisms. Extracts were lethal even at concentrations equivalent to as little as 0.25 mg dry leaf m1-1 , but inhibition decreased when extracts were prepared from leaves aged in the laboratory for 35 d (loss of anti-bacterial activity) or 90 d (loss of anti-algal activity). Extracts of leaves which had aged and dried several months in the field had no effect, except at very high concentrations (13 mg dry leaf ml-~ ) when the lag phase of growth was prolonged several days in a culture of the chlorophyte Platymonas sp. The active fraction in eelgrass leaves may be important in controlling initial growth of micro-organisms on eelgrass detritus, and it could determine the composition and activity of the epiphytic community on living leaves.