First principles of agriculture. By Edward V. Voorhees

Abstract

another series of experiments, one of the mineral elements; the crop secured in each experiment is found to be imperfect. Perfect growth is only reached when all the elements named are present. Pood obtained from the Atmosphere.-The leaves and roots are called organs of nutrition; the leaves take material from the air, the roots from the soil. The dry substance of a plant is made up chiefly of carbon, and the proper absorption of this element depends upon the activity of the leaves. The leaf is made up of rows of cells, placed side by side, which in the under portion are loosely held together, forming "air spaces" between them, and over the whole leaf there is a thin, transparent skin. This skin, called the " epidermis,'^is not entire, but is dotted with little holes called " stomata ; through these the atmospheric air passes freely into the cellular spaces in the leaf, and through the porous walls of the leaf cells, which contain a green substance called " chlorophyll." In these cells, containing chlorophyll, the carbonic acid of the air is broken up through the influence of light and warmth, and the oxygen set free and the carbon retained. This process is called "assimilation," and is active only during the daytime ; during the night the food, formed by day, undergoes a change, whereby it can be transferred in solution to the places where it is needed. Daylight, as also the presence of iron in the plant, is necessary for the formation of chlorophyll. In the daytime, growing plants purify the air by consuming the carbon ; in the night, the process is reversed, THE CONSTITUENTS OF PLANTS. 13 oxygen being then consumed. The quantity of oxygen set free by young plants is, however, greatly in excess of that consumed. The food directly supplied by the atmosphere is, therefore, chiefly carbon. The carbon absorbed by the plant, in connection with the hydrogen and oxygen of the water, forms starch, dextrine, sugar, fat, cellulose, substances serviceable in the growing plant, and to be stored away for future use in seeds, roots, and stems ; and the same elements, together with nitrogen and a little sulphur, form the albuminoids. All of these are vegetable substances with which we are familiar, and which are termed "organic.'' Pood obtained from the Soil.-Eoots are of two kinds,the " tap root,'' the chief use of which is to sustain the plant in an upright position; and the "fibrous root," which is engaged mainly in absorbing food from the soil. These roots are made up of cells, through the walls of which solid matter cannot pass ; all food absorbed by the root must be in solution. The surface membrane of the root, unlike that of the leaf, is not full of holes the absorption of solids is, therefore, impossible. The absorption of the solution by the root is obtained by means of what is called "diffusion." By this means water is absorbed, and, with the water, the dissolved food elements usually contained in the ash of plants. The absorption of food is, however, not confined to the taking up of ready formed solutions. The roo...

Prenatal exposure to alcohol, caffeine, tobacco, and aspirin: Effects on fine and gross motor performance in 4-year-old children.

“…Poorer balance in children of social drinking mothers is of particular interest because a recent report indicates kinetic tremor, axial ataxia, and other clinically significant motor deficits in children with FAS whose mothers were alcohol abusers (Marcus, 1987). The principles of behavioral teratology would predict larger magnitude effects (such as those reported by Marcus) to be associated with higher levels of exposure, whereas more subtle effects (such as those reported in the present study) would be predicted with lower levels of exposure (Voorhees, 1986). Riley and colleagues (Hannigan & Riley, 1989) produced gait abnormalities in a dose-dependent fashion in prenatally exposed rats and postulated that the effects were associated with hippocampal damage, noting that the same type of gait abnormalities had been produced by prenatal disruption of hippocampal development.…”

Metal Oxide Laser Ionization Mass Spectrometry Imaging (MOLI MSI) Using Cerium(IV) Oxide

“…17,18 One promising MOLI MS application using CeO 2 involves microbial identification using fatty acid profiling. 19 While conventional MALDI TOF MS has revolutionized the clinical laboratory workflow through the identification of bacterial isolates by their proteomic profile, differentiation and speciation of certain bacteria, including Acinetobacter, Listeria and Enterobacteraciae, have proven challenging due to intra-species similarities. 20,21 Fatty acid profiling using MOLI MS has been shown to not only improve genus and species level identification of these organisms, but has the granularity for even strain level identification 22 and differentiation of antimicrobial resistant and susceptible isolates, 23 a considerable improvement to current approaches utilized in clinical microbiology.…”

Cyclic Amp Level in Different Layers of Psoriatic Epidermis

“…In fact, there have been some attempts to determine cyclic AMP levels in normal epidermis, uninvolved and involved epidermis of psoriatic skin, which have resulted in conflicting data (7,10,11). This is probably due not only to differences in methodology but also difficulties in comparing two heterogenous tissues such as uninvolved and involved of involved skin had a significantly higher DNA content per tissue weight (50-100%) than upper half epidermis of involved skin.…”

“…Voorhees, et al (7,8) have cited a number of reports from the literature, suggesting that the increase in cyclic GMP levels is associated with increased proliferation while the increase in cyclic AMP levels is often associated with decreased proliferation.…”