Nutritional Factors in Plant Growth and Development - Paper Presented at the Fifty-Sixth Annual Meeting

The large number of recent publications on the physiology of plant development reflects a widespread, contemporary interest in this subject. Researches in this area deal chiefly with the effects of specific growth substances and mineral nutrients on functional and structural ontogeny. The major contributions on the physiology of growth substances have already been conveniently assembled in certain excellent monographs (36, 53, 283, 339, 424) and reviews (37, 422, 192). Recent researches on nutrition in relation to plant development have not as yet been comprehensively reviewed. Data in this field as a whole are extremely diverse, especially as they relate to the nutritional cycle of biennial and perennial crops (20, 259, 411). In typical annuals, however, certain common relationships seem to characterize the mineral, carbohydrate and protein metabolism such that a number o

Effects of Soil Aeration on Plant Growth and Root Development

Considerable is known concerning the immediate effect on root growth of excess carbon dioxide and shortage of oxygen in the soil. The ecologic importance of soil atmosphere in relation to root growth has also been studied. Very little work has been done on the formative and metabolic effects of continuous liberal soil aeration on plants so grown. A preliminary report is herewith presented of the formative effects of optimal air supply upon root and top growth in several types of plants whose roots differ in their oxygen requirements

The Effect of Light Intensity on Tissue Fluids in Wheat

Foliar chlorosis was observed to occur frequently during periods of strong insolation in grain plants growing humus soils to which lime had been added to correct acidity. An experiment was undertaken to determine the reasons for the increasing prevalence of chlorosis during periods of clear, sunny weather

The Teaching of Botany - Appraisal and Forecast

In undertaking a discussion of biology in education it is highly desirable to view the subject against the general background of American education as a whole. Among the nations of the world, the United States possesses the unique distinction of having mass education. We owe this policy to the shrewd foresight of the fathers of the American Revolution, to their recognition of the fact that the success of representative government depends upon an enlightened electorate. As an object of primary importance, George Washington enjoined the new nation to promote institutions for the general diffusion of knowledge. In his first inaugural address he stated that as government gives force to public opinion, it is essential that public opinion should be enlightened. Though we as individuals commonly regard education as a means of improving our economic status, American statesmen have never lost sight of its greater importance in making democracy feasible. Because the civic value of education far transcends its benefits to the individual student, a system of free public was established and the education made compulsory

Nutritional Physiology of Certain Dioecious Plants

Further study has been made of the metabolic expression of sex in shoots of typical dioecious hemp plants. Results obtained show significant differences in metabolism of corresponding shoot regions of the two sexes before as well as after the development of sexual dimorphism

Current Developments in Science and Biology Teaching

Though science and education as a whole are currently and properly geared to the war effort, it is commendable that teachers and administrators are, nevertheless, already giving foresighted attention to desirable patterns of postwar instruction and matters of permanent curricular policy. While perhaps no one can as yet predict the exact social pattern of a world at peace nor fully foretell its demands upon education, certain emergent trends already delineate the scope of the problem and the probable areas of major change. Science is destined to play an important role in peace as it has in war but with notable shifts in emphasis. It consequently becomes the moral obligation of scientists to inventory the situation, and to pool information with a view to formulation of a program of action which embodies the best professional judgment bearing upon science education in the postwar world. The ensuing discussion deals with certain important factors which seem destined to have a great influence on the teaching of science and biology