Mechanism of Protein Synthesis

Animal muscle proteins are stated by Rose (10) to contain 21 amino acids of which 10 must be derived directly from the food while 11 can be modified by transamination provided some other primary amino acid is supplied. Although storage and particularly seed proteins are relatively simple in their structural pattern and amino acid content, herbivorous, and eventually all, animals derive their amino acids entirely from plant products. It seems reasonable to assume, therefore, that leaf proteins are comparable in complexity and amino acid distribution to muscle proteins

Effects of Over Liming an Iowa Soil with Gypsum (Abstract)

A sample of Clarion loam soil taken near the U. S. Gypsum Co. plant at Fort Dodge, for which the owner claimed accumulated injury from dust deposits, showed no symptoms of high -Ca injury. Potted crop plants growing in the soil showed marked response to nitrogen and phosphorus added together, little or no response to potassium added alone to balance excess calcium ions, and responded positively to additional applications of gypsum at the rate of 100,000 pounds an acre

Recent Advances of the Forest in Iowa

At the time of settlement Iowa was definitely a prairie state with less than 20 per cent of its area covered by timber. Such a distribution of vegetation, coupled with short time observations, has led to the general assumption that prairie is the climax vegetation of the state. The writers have recently (7) assembled evidence that the present climate of Iowa is capable of supporting a forest climax. Prairie is therefore a subclimax associes maintained by its early establishment and by the marginal nature of the climate, but particularly by a combination of soil factors favoring prairie over woodland. The establishment of our classification depends upon evidence that forest is not only able to survive in Iowa, but that it has been able to invade the prairie at an appreciable rate under undisturbed conditions. Additional evidence of the spread of forest in Iowa, both after and before settlement, is presented here

Boron-Iron Relationships in the Growth of Tomato

7. Boron-iron relationships The work of Sommer and Lipman and of Johnston and Dore indicates that boron is required for the growth of plants representing eight families. Their results suggest that boron in small quantities may be an essential element for all plants. Before such a conclusion can be fully established it will, of course, be necessary to grow all plant species under the exacting conditions required for the elimination of boron from the culture medium. In the meantime any data which indicate that boron has a specific and indispensable function in the growth of any plant should be of value in the solution of this problem. Dr. Lewis Knudson, in a personal communication, suggested to the authors the possibility that boron served to balance other elements present in water cultures and particularly to reduce the toxic action of iron, rather than to function as a specifically essential element. The experiments reported here were performed to check the work of Johnston on the necessity of boron for the tomato and to determine whether any beneficial effects were correlated with the prevention of iron toxicity

Effects of light and soil moisture on forest tree seedling establishment

The present studies were designed to aid in the solution of forest tree seedling establishment problems common to stand conversion practices in Iowa. The primary objectives were: (1) to determine the minimum treatment needed to insure successful survival and growth; (2) to study the relationships of light and soil moisture in plant competition resulting from stand conversion; and (3) to evaluate five species of conifers - European larch, Scotch pine, eastern white pine, Norway spruce and red pine - for adaptability to region, site and underplanting. Field studies were made at the Brayton Forest in northeastern Iowa and consisted of ( 1 ) practical understory treatments to increase survival and growth of five underplanted conifers and (2) controlled experiments to evaluate overstory and understory competition in such plantings. Studies at the State Forest Nursery near Ames were planned to determine the relative growth and photosynthetic characteristics of three of the underplanted conifers (European larch, eastern white pine and Norway spruce) and two shrubby hardwood species ( dogwood and hazel) which offer serious understory competition in the forest