Nuclear Size and DNA Content of the Embryo and Endosperm During their Initial Stages of Development in Glycine max (Fabaceae)
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The Department of Agronomy seeks to teach the study of the farm-field, its crops, and its science and management. It originally consisted of three sub-departments to do this: Soils, Farm-Crops, and Agricultural Engineering (which became its own department in 1907). Today, the department teaches crop sciences and breeding, soil sciences, meteorology, agroecology, and biotechnology.
History
The Department of Agronomy was formed in 1902. From 1917 to 1935 it was known as the Department of Farm Crops and Soils.
Dates of Existence
1902–present
Historical Names
- Department of Farm Crops and Soils (1917–1935)
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- College of Agriculture and Life Sciences (parent college)
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Abstract
A technique was developed for isolating embryo sacs from ovules of soybean and for separating embryo from endosperm. Image analysis and cytophotometry were used to determine the relative mass of DNA and size of nuclei of endosperm and embryo cells. Analyses were done at the globular through late heart-shaped embryo stages to correlate ploidy level or nuclear size, and differentiation in these tissues. Mean size of embryo nuclei was fairly constant through all stages studied. Ploidy condition of the embryo was stable, 950/o99% of the nuclei were distributed in a bipolar pattern by relative mass at 2C and 4C. Few embryo nuclei (3%) had ploidy levels above 4C at the late heart-shaped embryo stage. Variability in size ofendosperm nuclei seemed correlated with the morphological state of these nuclei (free-nuclear vs. cellular). Most endosperm cells did not show significant polyploidy with 840/o-92% of nuclei in the expected 3C-6C range, but some nuclei with elevated ploidy levels were noted during endosperm cellularization. Endosperm senescence was correlated with nuclear DNA loss over time. Polyploidy seems to have no direct role in the early differentiation of the soybean embryo and endosperm, but these stable conditions may be necessary for the early establishment of the embryo.
Comments
This article is from American Journal of Botany 80 (1993): 1209.