Handbook of practical botany : for the botanical laboratory and private student / by E. Strasburger ; edited from the German by W. Hillhouse ; revised by the author, and with many additional notes by author and editor.

  • Strasburger, Eduard, 1844-1912.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Handbook of practical botany : for the botanical laboratory and private student / by E. Strasburger ; edited from the German by W. Hillhouse ; revised by the author, and with many additional notes by author and editor. Source: Wellcome Collection.

    74/514 (page 43)
    The root of Daucus carota (the Carrot) furnishes a very inter- esting object. The orange-red colour of this root arises from carmine and orange-red colour-bodies, which possess throughout a crystalline form. The most common shapes are found collected in Fig. 20. They are small rectangular plates or rhombs, the rhombs often acicularly elongated, and prisms of different lengths, often broadened out at one end to the shape of a fan. Such crystalline formations have often small uni- laterally projecting starch-grains attached to them; therefore, these crystalline struc- tures must be placed in the same category with chlorophyll and other colour-bodies. The colour-material which crystallizes out is here, however, what decides the shape. Only a small quantity of proto- plasm adheres to the crystal, and from this, therefore, the starch-grains also arise. If we examine also one of the variegated forms of our shrubs or trees, or else an herbaceous plant with leaves coloured reddish-brown, we see that the cells of the epidermis contain a rosy cell-sap, and that there- fore the joint action of the red of the surface and the green of the interior gives the reddish-brown compound colour. As to the. autumnal coloration of the Virginian creeper, Ampe- lopsis hederacea, we can decide that the rose-coloured cell-sap arises in the cells of the internal tissue, and not of the epidermis. The distinctive yellow autumn coloration of leaves depends on the yellow coloration of the disorganized chlorophyll-bodies, as is shown in the most beautiful way in the leaves of Ginkgo hiloha [^Salisburia adiantifolia~\, or, failing this, those of the various species of Maple. The autumnal brown coloration of leaves arises from a corresponding coloration of the cell-walls, chiefly, however, of the cell-contents, as is easy to determine in the case of the Oak. The starch-grains are found in specially individualized proto- plasmic structures. We have already learned to know the chloro- phyll-bodies as such, also the colour-bodies in which starch-grains are often present; and lastly, we have already made reference to the colourless starch-builders. Upon these last devolves the Fig. 20. — Colour-bodies from the root of the Carrot. Tartly with starch - grains (x510).