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Posts by Zenobia

    The simplest carbohydrates known to occur commonly in plant tissues are the hexoses (see Chapter IV) having the formula C6H12O6 , which is just six times that of formaldehyde, CH2O. Also, it is known that formaldehyde easily, and even spontaneously, polymerizes into more complex forms having the general formula (CH2O)n; trioxymethylene, C3H6O3 , being a well-known example. Further, both trioxymethylene and formaldehyde itself can easily be condensed into hexoses, by simple treatment with lime water as a catalytic agent. Hence, it is commonly believed that formaldehyde is the first synthetic product resulting from photosynthesis, that this is immediately condensed into hexose sugars, and that these in turn are united into the more complex carbohydrate groups which are commonly found in plants.

    In the Pacific, off the coast of Oregon and British Columbia, a seaweed is commonly found with stalks over 500 feet long, and in India the rattan palm climbs over the tree tops for great distances, a single stem not much thicker than a broomstick measuring over 700 feet long. The search by leaves for light and air results in the stems of some plants performing almost incredible feats.


    Whether it is one of the Big Trees with a great massive trunk, or the rattan palm with its sinuous winding through the topmost heights of the tropical forests of India, the result is always upward to a “place in the sun.”

    The use which a plant makes of the elements which come to it from the soil has been studied with great persistency and care by many plant physiologists and chemists. Many of the reactions which take place in a plant cell are extremely complicated, and the relation of the different chemical elements to these is not easily ascertained. It is probable that the same element may play a somewhat different rôle in different species of plants, in different organs of the same plant, or at different stages of the plant's development. But the usual and most important offices of each element are now fairly well understood, and are briefly summarized in the following paragraphs. It should be understood that a thorough and detailed discussion of these matters, such as would be included in an advanced study of plant nutrition, would reveal other functions than those which are presented here and would require a more careful and more exact method of statement than is suitable here. However, the general principles of the utilization of soil elements by plants for their nutrition and growth may be fairly well understood from the following statements.