. Introduction to botany. Botany. FOODS IN PLAJSfTS 39 some of the compounds of nitrogen, potassium, phosphorus, or other substances, these thmgs may be made into more complex foods known as proteins. INIany stages of the process n a cr of making these more com- plex foods are not known, and these are too intricate for ex- tended discussion at this time. The leaf or other parts of the plant may be used as the place ^^-here proteins are made. They may be made im- mediately after the carbohydrates, or later, but sooner or later some protein food is as necessary to the continued life of plants as
. Introduction to botany. Botany. FOODS IN PLAJSfTS 39 some of the compounds of nitrogen, potassium, phosphorus, or other substances, these thmgs may be made into more complex foods known as proteins. INIany stages of the process n a cr of making these more com- plex foods are not known, and these are too intricate for ex- tended discussion at this time. The leaf or other parts of the plant may be used as the place ^^-here proteins are made. They may be made im- mediately after the carbohydrates, or later, but sooner or later some protein food is as necessary to the continued life of plants as of animals. The soil is the usual source of the nitrogen, potassium, phosphorus, and other substances that are used iij. addition to the carbohydrates in making proteins. Although the air is 78 per cent nitrogen, this atmos- pheric nitrogen is not available to plants, except to certain bacteria which are to be discussed later. From the soil, compounds contain- ing nitrogen and other substances may be dissolved in water and then carried into the plants. Fertile soils are those which contain in available form large quantities of the tibiings which plants use for food-making. Replenishment and growth of new parts can take place only by means of foods, and since the plant makes its own supply, the importance of the process is Aery Fig. 27. Apparatus for collect- ing oxygen from "working plants Water plants are submerged with one end in the mouth of the grad- uate. Bubbles of oxygen pass upward from the cut ends of the stems and crowd out some water from the previously filled grad- uate. The ordinary test for oxy- gen—with a burning stick—wUl determine whether it is present. In such an experiment care must be taken to see that there is plenty of space about the collect- ing tube, to permit free passage of the gases that are in the water. After Ganong. Please note that these images are extracted from scanned page images that may have been digitally enhanced for read
Size: 1019px × 2451px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisher, booksubjectbotany
