Conversations on Vegetable Physiology

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: ON ROOTS. Mrs. B.?We are now to examine the structure of those organs, whose office it is to nourish and preserve the plant. In the nutrition of plants, six periods are to be distinguished: ? 1. The absorption of nourishment by the roots. 2. The transmission of nourishment from the roots to the different...
More Description

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: ON ROOTS. Mrs. B.?We are now to examine the structure of those organs, whose office it is to nourish and preserve the plant. In the nutrition of plants, six periods are to be distinguished: ? 1. The absorption of nourishment by the roots. 2. The transmission of nourishment from the roots to the different parts of the plant. 3. The developement of the nourishment. 4. The action of the air on plants. 5. The conversion of nourishment into returning sap or cambium. 6. The secretion of various juices from the sap. Plants being deprived of locomotion, as we have observed, cannot go in search of food: it is necessary, therefore, that nature should provide it for them in their immediate vicinity. Those simple elements, which are almost every where to be met with, water and air, constitute this food. Water not only forms the principal part of it, but serves, also, as a vehicle to convey what solid food the plant requires; and as a vegetable is unfurnished either with a mouth to masticate, or a stomach to digest, solid food can be received only when dissolved in water. In this state it is absorbed by the roots; for the root not only supports the plant by fixing it in the soil, but affords a channel for the conveyance of nourishment. If it does not fulfil this double office, it is not a root, but a subterraneous branch. Caroline.?But will not a branch, if placed under ground, become a root, and absorb nourishment ? I have seen the gardener fasten down branches of laurel and other shrubs, leaving only the extremity above ground; and these layers strike root, and become, in the course of time, separate plants. Mrs. B.?Striking root implies, that roots will (under certain circumstances) grow from a branch, but the branch itself cannot be converted into a roo...