Vegetative system

“ As every plant, whether small or great, is only an aggregate of a great number of cells, so, also, the life of a plant is nothing else but the sum of the activities of all the cells of which it is composed. The special province of the cells is to receive from the soil or atmosphere the water necessary for the various vegetative purposes, together with the nutritious materials dissolved in the watery and aerial fluids, and to circulate them through the whole body of the plant. ”

“ These vessels, when the warmth of the vernal sun hatches the young bud, serve it with a saccharine nutriment, till it acquires leaves of its own, and shoots a new system of absorbents down the bark and root of the tree, just as the farinaceous or oily matter in seeds, and the saccharine matter in fruits, serve their embryons with nutriment, till they acquire leaves and roots. This analogy is as forceable in so obscure a subject, as it is curious, and may in large buds, as of the horse-chesnut, be almost seen by the naked eye ”

“ The vegetable and the sensitive animal have been formed parallel to each other, yet in such a manner that the former being the lowest, contains only the dispositions unto the highest. There are consequently vegetative and animal organs, which take a parallel range. The animal grows upon a vegetable body. It may be aptly said, that the root of the plant becomes the mouth or head of the animal, the stem the trunk or visceral body, the blossom the sexual parts. ”

“ The organs of plants is almost the largest subject in the vegetable kingdom, but I have no time to mention more than one or two organs to-day. The root descends into the soil, the stems rise aloft, and the flowers bud out at the ends of them. ”

“ Light, heat, moisture, and soil are therefore to be considered as the agents required to exist in a certain balance, or proportion, in reference to the health or power of vitality of the plant. Within a certain amount of variation, health may persist in virtue of the power of selection, which appertains to the spongioles of the root in absorbing nutriment; and also as regards light, from the tendency which most plants have to accommodate themselves to any deficiency of this element, by presenting their leafy expansion in that direction where the most of its influence may be obtained. ”

“ Take the evolution of a seed into a plant, and what do you find? A tiny germ surrounded by a mass of nutrient matter; and before that tiny germ will show itself in root, and stem, and leaf above the ground and become visible to the eye of the observer on the earth, that nutrient material must be absorbed by the growing germ, and changed into the exquisite tissues of the plant that is to be. ”

“ Plants do not require a stomach,—the humus or soil to which they are fixed is the laboratory, where the nutritive matter is prepared in a state fit for absorption by the spongioles of their roots, and these correspond to the lymphatics of animals; after being taken up by the spongioles, this new fluid mingles with the sap, and passes to the leaves or breathing apparatus of plants, where carbonic acid gas combines with the crude vital liquid, and converts it into a condition fit for all the offices to be performed by the plant: viz. the growth of tissues, and the elaboration of secretions. ”

“ Such, then, is the laboratory of the leaf, the place where certain inorganic, lifeless substances such as water, lime, sulphur, potash, and phosphorus are transformed and converted into living and organic vegetable matter, and from which this is sent forth to build up every part of the tree from deepest root to topmost sprig. It is in the leaves also that all the food of man and all other animals is prepared, for if any do not feed upon vegetable substances directly but upon flesh, that flesh nevertheless has been made only as vegetable food has been eaten to form it. ”

“ So scanty was the stock of knowledge which the founders of vegetable physiology in the latter half of the 17th century found ready to their hand. While the physiological significance of the different organs of the human body and of most animals were known to every one, at least in their more obvious features, the study of vegetable life had to begin with laborious enquiries, whether the different parts of plants are generally necessary to their maintenance and propagation, and what functions must be ascribed to individual parts for the good of the whole. ”

“ When we consider to what an extent the time and power of work of the most eminent botanists was devoted after 1840 to long and difficult observations on the minute anatomy of plants, on cell-formation, embryology and the history of the development of organs, we cannot wonder if other parts of vegetable physiology, which require experiments on vegetation in plants, were cultivated but little and by the way only ”

“ Another essential factor is the nature and quantity of organic materials in the soil, whether leaf-mould and decomposing vegetable remains, stable manures, or other animal matters, all of which affect different species very differently, and produce very different results in different soils. ”

“ While the power of absorption in the roots and barks of vegetables is excited into action by the fluids applied to their mouths like the lacteals and lymphatics of animals.
2. The individuals of the vegetable world may be considered as inferior or less perfect animals; a tree is a congeries of many living buds, and in this respect resembles the branches of coralline, which are a congeries of a multitude of animals. Each of these buds of a tree has its proper leaves or petals for lungs, produces its viviparous or its oviparous offspring in buds or seeds ”

“ But when we attempt to consider how the particular secretions of different species and tribes of plants are formed; how the same soil, the same atmosphere, should in a leaf of the vine or sorrel produce a wholesome acid, and in that of a spurge or manchineel a most virulent poison; how sweet and nutritious herbage should grow among the acrid crowfoot and aconite, we find ourselves totally unable to comprehend the existence of such wonderful powers in so small and seemingly simple an organ as the leaf of a plant. ”

“ The deviations from the ordinary direction of organs partake for the most part more of the nature of variations than of absolute malposition or displacement. It must also be borne in mind how frequently the direction of the leaves, or of the flower, varies according to the [Pg 202] stage of development which it has arrived at, to unequal or disproportionate growth of some parts, or to the presence of some impediment either accidental or resulting from the natural growth of the plant. These and other causes tend to alter the direction of parts very materially. ”

“ There are undoubted animals which produce the essential material of vegetable fabric, or build up a part of their structure of it, or elaborate the characteristic leaf-green which, under solar light, assimilates inorganic into organic matter, the most distinguishing function of vegetation. On the other hand, there are plants—microscopic, indeed, but unquestionable—which move spontaneously and freely around and among animals that are fixed and rooted. ”

“ In addition, all animals manifest those transitory changes of form which we class under irritability and contractility; and it is more than probable, that when the vegetable world is thoroughly explored, we shall find all plants in possession of the same powers, at one time or other of their existence. I am not now alluding to such phenomena, at once rare and conspicuous, as those exhibited by the leaflets of the sensitive plant, or the stamens of the barberry, but to much more widely-spread, and, at the same time, more subtle and hidden, manifestations of vegetable contractility. ”

“ The essential difference between plant and animal is a physiological one, a difference in the method of nutrition. A typical green plant is able to live independently of other organisms and to build up its substance from simple gases in the air and inorganic salts in the soil or water, provided that certain conditions of light and moisture be present in its environment; this is the so-called holophytic method of nutrition. ”

“ That the Roots increase their Fibres every time the Earth is stirr’d about them.
That the stirring the Earth makes the Plants grow the faster.
Leaves are the Parts or Bowels of a Plant, which perform the same Office to Sap, as the Lungs of an Animal do to Blood; that is, they purify or cleanse it of the Recrements, or fuliginous Steams, received in the Circulation, being the unfit Parts of the Food; and perhaps some decay’d Particles, which fly off the [14] Vessels, through which Blood and Sap do pass respectively. ”

“ True, we cannot instance the automatic performances of the vegetable as identical with the similar endowments of animal life, but still they indicate a sympathy, a harmony existing between the two organizations, and show us how closely the great principles of animal and vegetable life converge. Indeed, as they approach the common centre, the little cell that is the habitation of both, it is perhaps impossible to say, here begins animal and there vegetable life. ”

“ Among the phenomena of vegetation in woody plants, there is scarcely one so striking as the outflow of watery sap from wounded vines and from some tree-stems in the spring. This phenomenon, like the outflow of milky juice, gum, resin and the like, could not fail to be regarded with lively interest by those who occupied themselves with vegetable physiology in the 17th century. ”

“ In the first place, the enormous holdfast, ensured by the millions of points of adherence, enables the plant to withstand even powerful lever actions from above, and provides fixed points against which the root-tips can work as they drive deeper into the soil. In the second place, the intimate contact of the root-hairs and particles of soil, ensures that the films of water held by surface-action on the soil-particles and root-hairs shall be in continuity with the water saturating the cell-walls of the latter, and therefore with the protoplasm and cell-sap in their interior. ”

“ Henceforward, perhaps for a thousand years, this life goes on, active in summer and dormant in winter, absorbing the sunlight as a motive power which it controls and guides. Its instruments are the discriminating cells at the extremities of the root-fibrils, which search for, select, and absorb the crude aliment adapted to the needs of the plant to which they belong, and the chlorophyl cells--the lungs and stomach of the tree--in the leaves. ”

“ It has been again and again pointed out that the phyletic development of the vegetable kingdom proceeds with regularity and according to law, as we see in the preponderance and constancy of so-called purely ‘morphological’ characters in plants. The formation of natural groups in the animal and vegetable kingdoms compels us to admit that organic evolution has frequently proceeded for longer or shorter periods along certain developmental lines. ”

“ Like all other sciences, plant physiology has developed in response to the demands of life. As physics and chemistry had their basis in the industries, so plant physiology grew by each experience gathered from agriculture, horticulture, and sylviculture. Even if the origin of plant physiology be not historically demonstrable as a result of the demands of practical life, still a portion of our terminology would bear witness to the correctness of the assumption. ”

“ When we reflect that the constant removal of water in the leaf, both as such, and as the only carrier of food supplies from the roots, depends in such large measure upon the functioning of these guard cells, then we come to some realization of their importance to the plant. ”

“ The saline matter may not be taken up, even when the soil is rich in such ingredients, from the functional derangement into which the roots or digestive organs have been thrown by the unnatural circumstances in which it has been placed. A plant is composed, like all organized bodies, of a certain number of proximate principles, which are more or less numerous in different kinds. ”

“ Vegetation is, however, tolerably abundant—tamarisks, oleanders, kafas, euphorbias, the milk bush, rhamnus and acacias being the most common and most characteristic forms of vegetable life, and pools of water are frequent. ”

“ These buds of plants, which are thus each an individual vegetable, in many circumstances resemble individual animals, but as animal bodies are detached from the earth, and move from place to place in search of food, and take that food at considerable intervals of time, and prepare it for their nourishiment within their own bodies after it is taken, it is evident they must require many organs and powers which are not necessary to a stationary bud. ”

“ Sterility from the excessive development of the Organs of Growth or Vegetation.—Plants which from any cause grow too luxuriantly, and produce leaves, stems, runners, suckers, tubers, bulbs, &c., in excess, sometimes do not flower, or if they flower do not yield seed. To make European vegetables under the hot climate of India yield seed, it is necessary to check their growth; and, when one-third grown, they are taken up, and their stems and tap-roots are cut or mutilated. ”

“ The animal grinds down the fibre and the tissue of the plant, or the nutritious store that has been laid up within its cells, and converts these into the substance of which its own organs are composed. The plant acquires the organs and nutritious store thus yielded up as food to the animal, from the invulnerable air surrounding it.”
“But animals are furnished with the means of locomotion and of seizure — they can approach their food, and lay hold of and swallow it; plants must wait till their food comes to them. ”