. Lessons in botany. Botany. MOVEMENT IN PLANTS DUE TO IRRITABILITY. IOQ of the shoots will soon turn upward again. Young bean plants growing in a pot began within two hours to turn the ends of the shoots upward. Horizontal leaves and shoots can be shown to be subject to the same in- fluence, and are therefore diageolropic. 189. Influence of light. — Not. Pumpkin seedling showing apogeotropism. Seedling at the left placed hori zontally. In twenty-four hours the stem has become erect. only is light a very important factor for plants during starch formation, it exerts great influence on plant gr
. Lessons in botany. Botany. MOVEMENT IN PLANTS DUE TO IRRITABILITY. IOQ of the shoots will soon turn upward again. Young bean plants growing in a pot began within two hours to turn the ends of the shoots upward. Horizontal leaves and shoots can be shown to be subject to the same in- fluence, and are therefore diageolropic. 189. Influence of light. — Not. Pumpkin seedling showing apogeotropism. Seedling at the left placed hori zontally. In twenty-four hours the stem has become erect. only is light a very important factor for plants during starch formation, it exerts great influence on plant growth and movement. Demonstration 29. 190. To prepare plants grown in the dark —Three or four weeks be- fore these plants are wanted for study the teacher may plant a sufficient number of seeds (radish or other seeds) in small pots for the class to study. Several different kinds of seeds may be used for comparison if desired. Place one lot of the pots in a warm but very dark place. They may be put in a box, and the box can be then covered with two or three layers of black cloth, sufficient to shut out all light. Keep the box in a warm room, and oc- casionally open it to water the plants if necessary. The lot kept in the light should have the same temperature conditions. If preferred the pupils can plant the seeds, and place those to be grown in the dark in a common box. This is preferable if it is convenient for the pupils to do it. Exercise 41. 191. Influence of light on the growth of plants.—When the plants have grown for about two weeks they will be ready for study. Compare the plants grown in the dark with those grown in the light. Which lot have the longer stems? What influence then does light have on growth in. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Atkinson, George Francis, 1854-1918. Ne
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