A double begonia sempervirens on my kitchen windowsill.
Most of the plant is Carbohydrates, which are any of a group of organic compounds that includes sugars, starches, celluloses, and gums and serves as a major energy source in the diet of animals. These compounds contain only carbon, hydrogen, and oxygen, usually in the ratio 1:2:1., with the general composition ratio of CH2O, such as Glucose, C6H12O6, and Cellulose, (C6H10O5)n . The C and O come from carbon dioxide which is the main source for the dry mass of the plant. The H comes from H2O (water). The atomic weights of Carbon, Oxygen and Hydrogen, are 12, 16 and 1, respectively. The molecular
weight of CH2O is 30 so 2/30 x 100 =3D . So 6.7 % of its mass comes from water and 93.3 % from Carbon dioxide. This figure is apart from the water itself, of which a living plant may contain about 50%. About 5% of the dry mass consists of mineral nutrients from the soil although this can be higher in some species.
What we can say is that a plant is designed to construct itself from mostly air and water, with elements from the soil needed in only minute quantities, as in, for example, catalysts. The main elements needed from the soil are potassium and phosphorus, and every element which makes up a plant has its own unique cycle for reuse by other plants and animals. In some soils where they is a lot of rain it is better for these elements to be in a living organism than for them to be freely available in the soil where they would be leached out by rain, or just the opposite where these elements would be concentrated into a dangerous level in the ground water. All of this gives evidence , to me at least, of a supremely wise designer.
bambootiger 