Two seaweed suspensions, obtained from whole brown algae <I>Ascophyllum nodosum</I> (Linnaeus) Le Jolis (ANS), or lamina of <I>Laminaria hyperborea</I> (Gunn.) Foslie (LHS), were evaluated for their effects on seed germination and seedling growth of barley (<I>Hordeum vulgare</I> L.) and lettuce (<I>Lactuca sativa</I> L.). The seaweed suspensions (SWS) tested had mineral composition similar to that of fresh algae, and mineral concentrations at levels reflecting the dilution of the product during the manufacturing process. The activity of growth regulating substances found in the SWS were too low to be of physiological significance. When pre-germinated seeds were exposed to SWS at 10% or higher, radicle growth was inhibited both in barley and lettuce to a similar extent. The polyphenol content in ANS was found to be responsible for these effects in lettuce seedlings. For LHS unknown compound(s) were present in the supernatant, active only in the light. The compound(s) was(were) organic, heat labile above 60<SUP>O</SUP>C, degradable by microbial activity and likely not to be a protein. A growth promoting compound that increased lettuce cotyledon expansion in the light and hypocotyl elongation in the dark, was identified as potassium. Priming barley or lettuce seeds in SWS was beneficial, and adhering algal material provided additional nutrients to the seeds, compensating for leakage losses. Priming for 12 hours with a 24 hour re-drying period did not reduce seed viability, or increase the number of dead seeds or abnormal seedlings. When germinated under optimum laboratory conditions, the mean germination time of primed seeds, irrespective of initial seed vigour, was generally reduced. Priming in SWS was not superior to water treatments. However, seedling emergence and growth of barley under greenhouse conditions was promoted by priming with ANS, and was better than priming in water.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:657881 |
| Date | January 1996 |
| Creators | Mòˆller, Michael |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11857 |
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