Degree Type

Dissertation

Date of Award

1987

Degree Name

Doctor of Philosophy

Department

Agronomy

Abstract

The effect of selected nutrients on the dry weight and chemical composition of soybean and corn seedlings was studied in the preemergence stage under growth chamber conditions. The first of four experiments was designed to choose the appropriate rooting medium. The sand method proved the best way to show the treatment effects on the dry weight of roots and shoots;The second and third experiments studied the effect of mineral nutrients on dry weight and chemical composition of seedling parts at three stages of growth. One used Harcor soybean with Ca, Mn, and a mixture of other nutrients. The other experiment used a corn hybrid, B73 x Mo17, with Ca, K, P, N, and micronutrients. In both species, Ca increased root and shoot dry weight. To a lesser degree, the nutrient mixture increased the dry weight of soybean roots and shoots. In corn, K increased the shoot weight and micronutrients decreased the dry weight of corn roots and shoots. Application of Ca had a greater effect than any of the other nutrients on the chemical content and concentration of the nutrients in the seedlings. Also, changes in the concentration and content of a particular element depended on its presence or absence in the nutrient solution;Since Ca was the factor that most influenced growth, the final experiment was designed to measure the effect of different levels of Ca with A2 and Pride B216 soybean and with the corn MBS 484 x B73. It was found that 1 mM of Ca was sufficient to obtain the maximum increase in the dry weight of roots and shoots of soybean and corn;A direct relationship was found between increasing Ca levels and concentration of Ca, and Ca content in roots and shoots of corn and soybean. With corn, an inverse relationship was found between Ca levels and N, P, K, Zn, and Mn concentration in roots and shoots. In soybean, an inverse relationship between Ca levels and concentration of Zn and Mn in roots and shoots was observed;The Ca present in roots and shoots of corn and soybean seedlings was supplied by the nutrient solution, since no Ca depletion from the cotyledons was observed.

DOI

https://doi.org/10.31274/rtd-180813-8609

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Jaime Daza-Baquen

Language

en

Proquest ID

AAI8716758

File Format

application/pdf

File Size

169 pages

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