. Cassell's popular gardening. Gardening. Fig. 42.—Simple Toothed Leaf of the Linxe-tree showing the stalk and the Fig. THE LIFE-HISTOEY OF PLANTS. Bt Dr. Maxwell T. Masters, IsUTEITION: THE LEAVES AND WHAT THEY BO. n^HE most important organs of the plant, so far as JL its nutrition is concerned, are the roots and the leaves. The roots, as we have seen, take from the soil the greater part of the water required by the plant, they absorb the mineral and earthy matters, espe- cially the nitrates. Their chief, and sometimes only, field of operation is the soil. AU this has been
. Cassell's popular gardening. Gardening. Fig. 42.—Simple Toothed Leaf of the Linxe-tree showing the stalk and the Fig. THE LIFE-HISTOEY OF PLANTS. Bt Dr. Maxwell T. Masters, IsUTEITION: THE LEAVES AND WHAT THEY BO. n^HE most important organs of the plant, so far as JL its nutrition is concerned, are the roots and the leaves. The roots, as we have seen, take from the soil the greater part of the water required by the plant, they absorb the mineral and earthy matters, espe- cially the nitrates. Their chief, and sometimes only, field of operation is the soil. AU this has been told in preceding chapters. The leaves take from the air the greater part of the gases required to feed and build up the plant, and possibly some of the water. In addi- tion to this, the leaf is the great laboratory, or factory, in which the substances taken in by the root, as well as by its own exertions, are blended and modified so as ultimately to serve as food for the plant, to build up its substance, fabricate its cell- waUs and its protoplasm, form and store away the starch and other ingi-edients which render the organs of reserve so important to the plant. In doirg all this it absorbs some gases and gives out others; it throws off superfluous water and, under cer- tain conditions, absorbs it. Much of its work can only be accom- plished under the influence of solar light. The work that it does in common with the root and other organs of the plant it can do irrespective of light, pro%ided heat, moistm-e, and other condi- tions be suitable; but the special woi-k of the leaf, which we shall have to consider in this section, can only be done when the leaf is exposed to light, and what is true of the leaf is true of all parts of plants that are green in colour, such as the young shoots or the unripe fruit. of Leaves.—In botanical lan- that bears a leaf is a stem or a branch of a stem. The root is not a stem, because it bears no leaves; the tuber of a Potato or of a Jerusa
Size: 1496px × 1670px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1884
