Experiments with plants
Winthrop John Van Leuven Osterhout
Paperback
(RareBooksClub.com, March 6, 2012)
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...of the tip of the stem by the overlapping bud-scales and young leaves is due to the fact that these organs grow faster on the lower side than on the upper, thus causing them to curve inward. When the bud opens, the reverse process occurs, growth becoming more rapid on the upper side. In some leaves this condition persists, giving them a permanently curved appearance or causing them to flatten themselves out on the ground as in the Dandelion (experiment by placing a Dandelion upside down with its root wrapped in moist cotton). Study the unrolling of Fern leaves. In this connection let us consider the general conditions of growth. Every one is familiar with the expression " growing weather," which clearly indicates that growth depends on certain conditions. We may experiment on three of these--namely, warmth, moisture and light. For this purpose obtain a lot of seedling plants (of the same kind) as similar as possible in respect to vigor and general condition. They must be grown in pots or boxes. (a) Temperature.--Select three pots, and mark the stem of each plant with ink two inches from the tip. Cover each pot with an opaque cover (a pasteboard cylinder or box will answer), to exclude the light. Insert a thermometer, if possible, in each, so that it may be conveniently observed. Place one pot in the warmest spot about the building, another in the coolest, and the remaining one in a place of medium temperature. After forty-eight hours, measure the growth of each. (b) Moisture.--Use two potted plants, provided with opaque covers to exclude light, keeping them all together in a spot where the temperature is most favorable to growth. Before commencing the experiment, allow one of them to suffer from lack of water, keeping the other well watered. Then ...