An Ultrastructural Study of Fresh and Ensiled Alfalfa Using the Light and Transmission Electron Microscope

<p>Late bud alfalfa was sampled prior to cutting and after 17 and 51 days of ensiling. Leaf and stem tissue were separated and immediately placed in 2.5% glutaraldehyde followed by 1% osmium textroxide for fixation. Following acetone dehydration, samples were embedded in Spurr plastic for examination under the light (LM) and transmission electron (TEM) microscopes. Light microscopy was used to differentiate cell types and tissues, e.g. epidermis, chlorenchyma, phloem, xylem, and pith. Iodine staining (LM) showed starch localization in chlorenchyma cells. Transmission electron microscopy analysis showed starch localized in chloroplasts of chlorenchyma. Leaf cells averaged nine chloroplasts per cell section and eight starch granules per chloroplast section. Stem eel.ls averaged four chloroplasts per cell section and three starch granules per chloroplast section. After ensiling, only remnants of starch were observed. Lipid was visible as coalesced droplet in ensiled tissue, but was incorporated in the intracellular structures of fresh tissue e.g. membranes. Intracellular material of fresh tissue was localized on the inside periphery of the cell. Vacuoles occupied the central portion. This integrity was lost in the ensiled samples. Light microscopy and TEM showed cell wall breakage in chlorenchyma and pith cells, but cell walls from vascular bundle and epidermal cells remained intact. Some midele lamella disintegration occurred in all cellular regions. Results indicate the LM and TEM could be useful as tools in forage research.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - Open Access

Discipline thesis:degree_discipline

Dairy Science

Year dc:date.available

1979

Author dc:creator

• Lazo-Davis, Janet Louise

• Dairy Science

Statement dc:rights

• <p>In Copyright - Non-Commercial Use Permitted<br /><a href="http://rightsstatements.org/vocab/InC-NC/1.0/">http://rightsstatements.org/vocab/InC-NC/1.0/</a></p>

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/1296

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-2297