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| Select item below | Question and Answer Archive |
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I have some questions about the effect of nitrate on Lemna. How much nitrate were you using? as little as 10 parts per million (10mg/litre) makes a considerable difference. Cambridge tap water has 30ppm and is about right for steady growth without algal competition. Do you think you could tell me why too much nitrate is harmful to lemna? Too much nitrate will cause algae to grow very quickly. Algae have a daily cell number doublng, at the very least, whilst Lemna a 2.4 day doubling at most. Lemna therefore loses out and the pot grows green with algae. What the biological significance is of nitrate on the growth of lemna? The answer to this is as for any other plant (makes proteins) also high nitrate and low oxygen in the water with added decay bacteria induces dentrification. Nitrite (reduced nitrate) is toxic to many forms of life. I dont think nitrate alone is harmful at all. What is the natural lifespan of lemna, i.e. were the plants dying naturally or was it the effect of the nitrate? Lemna is immortal.......It goes on forever. One frond will age of course and die. It will not last more than three weeks at summer temperatures, in that time it may have budded half a dozen times from each pouch (left and right) either side of the frond. Stephen Tompkins
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