Practical physiology of plants / by Francis Darwin and E. Hamilton Acton.

  • Francis Darwin
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Practical physiology of plants / by Francis Darwin and E. Hamilton Acton. Source: Wellcome Collection.

    319/354 page 295
    CH. XVIl] EXPERIMENTS. and cellulose in B will be the amounts formed per day by the weight of Spirogyra taken. (2) Shew that formation of starch is influenced by supply of inorganic salts. Take some young leaves of Sparganium nutans (or shoots of Elodea canadensis) and gi'ow one portion {A) in pure distilled water, and another portion (B) in a culture solution, both being freely exposed to light and air, for several days. Determine in portions of A the p. c. of starch (if any) and the p.c. of (sulphated) ash. Do. in portions of B. (3) Trace the changes which occur during germina- tion in the reserve materials of an oily seed under different conditions. Take three equal weights (about 10 grs. each) of air- dried hemp-seeds (-4), (B), (C). Allow B and G to germinate on damp asbestos cloth and when the plumules have reached a length of 2—3 cm., place B in a bell-jar arranged so as to exclude COa^: place G under similar conditions, but with free access to CO2: leave B and G exposed as much as possible to light for about a fortnight. Then kill them by chloroform vapour and dry at 25°—30°. Note weights (air-dried) oi A, B, and C. Make extracts of aliquot portions of ^, jB, and G, and determine for each of them, (1) nitrogenous compounds, (2) oils and fats, (3) sugars, (4) starch, (5) cellulose.
    digitised image 1
    digitised image 2
    digitised image 3