The Plant World; An Illustrated Monthly Journal of Popular Botany Volume 19

The Plant World; An Illustrated Monthly Journal of Popular Botany Volume 19

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1916 edition. Excerpt: ...same as Experiment A, viz., 5 cc. of solution + I cc. or 2 cc. of ammonia solution per culture, making 6 cc. and 7 cc. respectively TABLE 4 Experiment C. Aspergillus cultures in Czapek's solution with 5% dextrose. 5 cc. per culture + 1 cc. or 2 cc. of ammonia solution added, making 6 cc. or 7 cc. respectively, per tube was unnecessary until there should be found some indication of a gain in nitrogen over that furnished at the outset, which had been measured with the greatest possible accuracy and without any apparent loophole or cause for doubt. In other words it was considered that it would be soon enough to look for the sources of fixation or gain and the relation to dry weight carbohydrate economy, etc., after some fixation or gain had been demonstrated and not before that. Accordingly, cultures were continued as before, varying the media slightly and the temperature considerably, some being grown at room temperature, about 20C. but mostly in the incubator at about 29C. as this had been shown by Will,17 Nitinsky18 and Czapek19 to be the optimum temperature for this organism. The criticism might be made that the method failed to get all the nitrogen out of the cultures and that as a result no gain was shown; and this point calls for serious consideration. It is possible that the losses in D, E, G, and H are due to this cause; but Experiments A, B and C return exactly the amount of nitrogen that was supplied, and Experiment I, With Azotobacter, shows a liberal gain or fixation. The large loss shown in Experiment F, especially, was doubtless largely due to a change in the method of digestion, by adding a drop or two or H2S04 and then evaporating until SO fumes appeared. There is this feature in favor of the blowing-over method...show more

Product details

  • Paperback | 122 pages
  • 189 x 246 x 7mm | 231g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236910168
  • 9781236910165