The plants are expert chemists, and the reactions in which they engage are, on the whole, much simpler than those which go on in the bodies of animals. Vegetable tissue is largely carbon, hydrogen, oxygen and nitrogen. It is a curious fact that instead of using the abundant carbon compounds present in decomposed animal and vegetable matter of the soil the plants get most of their carbon from the carbon dioxide of the air. Inversely, they largely disregard the seventy-eight per cent nitrogen of the air, and extract that element from the complicated compounds found in the soil, or take it from the air only by aid of certain Bacteria.
Certain plants manufacture lime and metallic oxides with which to harden the protective armour they wear. Many others generate nitric acid, carbonic acid and ammonia for use in their interior laboratories. Roots nearly always secrete a fluid which aids in the absorption of minerals from the earth. It is so powerful that quartz, flint and limestone are often scratched and corroded by its action. Above and below ground, plants are active chemical laboratories.
The differences of taste, smell and colour which characterize leaves, blossoms and fruits are due to the presence of various organic compounds. These are largely volatile oils which are more complex than the substances involved in the simpler life processes. The slow or rapid evaporation of these oils influences the strength and character of an odour. When a flower or fruit passes through infinite gradations of colour, we can give no adequate account of the chemical changes involved. All we can do is to observe and to note. Sometimes infusions of iron sulphate or other chemicals in the soil darken the hues of flowers. Gardeners profit by this fact in the cultivation of certain varieties of Hortensia.
The chemical activities of plants are of incalculable value to man. They change air, water and mineral salts into forms easily assimilable by the human system. Eliminate all the vegetable life from this planet, and the animals, including man, would perish in a few months. Man has also learned to make abundant use of plant substances for innumerable purposes. Potash is an example of how the plants come to our aid in furnishing us a valuable chemical. It is extracted from wood, Seaweed and Banana stalks. These plants have discovered a way of getting it out of its well-nigh insoluble earth combinations with silica. If it had not been for certain industrious sea plants, man would probably never have been aware of the important chemical twins, bromine and iodine, so important in photography. These plants patiently filter them out of sea water where they exist in microscopic quantities, and build them into their bodies. Beer is possible because germinating grains transform amylum or plant starch into sugar. We find ripe fruits palatable because their acids change into sugar under the influence of sunlight.
Man seems to have outstripped the plants in the use of light, heat, electricity, and other physical forces, but the plants have more engineers among them than we imagine. In the fact that man has just learned to extract nitrogen from the air by the agency of electrical discharges, lies the probable explanation of how the plants have been doing the same thing for years. It is believed that the minute electrical discharges continually going on between the different air strata make small quantities of nitrogen assimilable for the plants. The micro-organisms which also furnish nitrogenous material to the plants may get nitrogen from the air in the same way. It is quite certain that the plants are affected by the chemical state of the atmosphere.
Everyone knows what an important part light plays in plant physiology, but the fact that certain plants produce their own lights, while generally known, is not universally understood. The Austrian naturalist, Heller, was the first to demonstrate that the glowing of decayed wood at night is caused by emanations of light from Fungus growing in the cavities. A similiar organism called Luminous Peridineas (sometimes classed as an animal) is responsible for the phosphorescence of the ocean and the night lights of many flowers.
About three hundred species of Bacteria and fifteen species of Fungus are recognized to be luminous. The dead leaves of the tropical Banibusa, Nephelium and Aglaia often glow at night with the light of these tiny creatures. Ordinary dead Oak and Beech leaves are luminous, sometimes shining in spots, but frequently glowing throughout with a soft, white, steady light. These miniature incandescent lights often shine for days, weeks and months, and with abundant nutriment at hand, sometimes for years. The light is slight in intensity, but uniformly steady and white, green or blue-green in colour. It is strong enough to enable the plants on which the Fungus grows to photograph themselves by long exposure to sensitized plates. The fungus light has also been used to influence the heliotropic movements of plant seedlings. In fact, a colony of Fungus has sometimes been placed in an electric light bulb and made thus to serve as an illuminant.
No matter from what angle we study the plants, we find that they are extremely scientific. They conduct themselves and all their activities in a way to always get the best results. They show knowledge and acquaintance with all of Nature’s laws, and they have learned to apply many of them with startling success.
MODERN NATURE WORSHIPPERS