Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 95-99). Also available on the Internet.

Canola (Brassica napus) is a $19.3 billion industry for the Canadian economy annually, largely because of the demand for the oil derived from the seeds of this crop plant. Seed development and accumulation of important nutrients requires coordinated interactions between all seed regions, including the funiculus. The funiculus is a structure of the seed that serves as the only connection between the filial seed and the parent plant, yet its development and underlying transcriptional programs have not been explored. Using light and transmission electron microscopy, I completed an anatomical study of the funiculus over the course of development, from the mature ovule to the post-mature green seed stage. My results show that all three plant tissue systems of the funiculus undergo profound changes at the histological and ultrastructural level. To understand the programs that orchestrate these changes in the globular stage funiculus, I used laser microdissection coupled with RNA-sequencing. This produced a high-resolution dataset of the mRNAs present in each of the three tissue systems of the funiculus. Various clustering analyses and gene ontology term enrichment analysis identified several important biological processes associated with each tissue system. My data show that cell wall growth occurs in the epidermis, photosynthesis occurs in the cortex, and tissue proliferation and differentiation occurs in the vasculature. The importance of these processes in supporting overall seed growth and development is discussed, which can have profound implications in the genetic modification of the canola seed through manipulating the transcriptional activity of the funiculus.

This work helps increasing our general understanding of how plants behave under altered hydrological conditions which occur along rivers regulated by hydropower dams. Usually, natural-real environments are highly unpredictable. Consequently, research based on field data becomes challenging and results may contain uncertainty. Here, an experimental design in a greenhouse is developed. Several measured attributes of selected plant species related to germinability, performance and survival were used as indicators of the impact of watering treatments which mimic hydrological regime spilled through hydropower dams. Specifically, direct effect<img src="https://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png" /><img src="https://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png" /> of water availability changes, water fluctuation and water flooding, and indirect effect<img src="https://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png" /> through derived erosion, were tested. Results benefitted from indoors controlled conditions. They showed significant different responses depending on species and hydrological changes. In general, Helianthus annuus was slightly affected. It deal well flooding conditions, and was comparatively more affected by water fluctuation and stress. Carex and Filipendula species showed the highest sensitivities to flow. They hardly germinated under any water treatment (few germinations under flooding for Carex and few under water fluctuation for Filipendula) and performance was very low for germinates. Betula pubescens was in between. Contrarily to Helianthus, it was severely affected by flooding, and also for water fluctuation. It survived water stress better than Helianthus, but looked unhealthy. All species seeds but Helianthus were highly eroded. However, erosion resulting<img src="https://cdncache-a.akamaihd.net/items/it/img/arrow-10x10.png" /> from water fluctuation was relatively higher than from prolonged flooding. Differing responses are the result of morphological and physiological characteristics of the species which enable them to success under certain stressful conditions, such as water scarcity and anoxia. These results objectively inform about tolerance limits of selected species to key hydrological conditions and are useful for riparian areas management and environmental flows designs.

Research was undertaken to optimize propagation of the southern China native Camptotheca acuminata Decaisne, source of the medicinal compound camptothecin that is used in the treatment of multiple forms of cancer and other diseases. The study focused on cutting propagation, micropropagation, and seed storage. Softwood cuttings of C. acuminata rooted readily in intermittent mist (4 sec on every 6 min.) in coarse vermiculite when treated with K-IBA (indolebutyric acid, potassium salt) quick dips ranging from 4.14 mM to 37.3 mM, with a 29.0 mM quick dip (5 sec.) promoting 82% rooting with little foliar damage. Actively growing shoot tip explants were tissue cultured on media containing Murashige and Skoog, Gamborg's B5, and Woody Plant Medium (WPM) salts in factorial combinations with BA (benzyladenine). WPM containing 4.44 μM BA promoted excellent shoot proliferation; microcuttings were rooted, acclimated, and grown in the greenhouse. Seeds stored in polyethylene bags in a refrigerator (4°C) or freezer (-20°C) maintained good germination (81% and 80%, respectively) while seeds stored at room temperature (25°C) in polyethylene bags lost germination ability quickly (58%) after one year of storage. C. acuminata is readily adaptable to modern nursery techniques for either vegetative or seed propagation.

Understanding the mechanisms plants utilize for seed storage protein (SSP) synthesis, transport and deposition have the potential rewards of enabling high yields of modified or foreign proteins. Hayashi et al. (1999) indicated that the machinery devoted to the synthesis of protein storage vacuoles in cotyledon cells can be induced in vegetative tissue by the constitutive expression of a pumpkin 2S albumin phosphinothricin-acetyl-transferase gene fusion (pumpkin 2S-PAT) resulting in the biogenesis of precursor-accumulating (PAC) vesicles in Arabidopsis leaves. This discovery was the impetus behind the work described which sought to examine this phenomenon further by ectopically evoking SSP trafficking and vesicle biogenesis machinery in leaves. With the aim of elucidating the mechanisms necessary to evoke PAC vesicle biogenesis, a suite of constructs including the pumpkin 2S-PAT and analogous napin-PAT and napin-GFP variants were synthesized. Analysis of these transgenes in Arabidopsis revealed that the pumpkin 2S albumin has a capacity unique from napin peptides to result in fusion protein accumulation. Further, the truncated pumpkin 2S albumin peptide and the pumpkin 2S albumin C-terminus were found to direct deposition to vesicles; however, the C-terminus alone was not enough to direct deposition to vesicles unless combined with a significantly shortened napin peptide. An increased ER protein throughput was correlated to trafficking of the fusion protein by Golgi-independent mechanisms resulting in stable accumulation of the unprocessed protein whereas less ER throughput indicated passage through the Golgi-dependent pathway resulting in accumulation of a processed variant. At the level of gene expression, as examined by a microarray study, both inducible and constitutive ectopic expression of pumpkin 2S-PAT resulted in substantial perturbations of the endomembrane system affecting protein folding, flowering time and ER-associated biosynthetic functions which indicated that modulation of flowering time and photoperiodism are highly dependent on protein trafficking and vacuolar biogenesis mechanisms and that high ER protein throughput occurs at the expense of biosynthesis and cessation of ER functioning.

3 pp. / The influence of crop species, seed size, seed viability, seed depth,irrigation practices,stand establishment and uniformity, seeding equipment, planting date, crop variety, and planting configuration on optimum seeding rate for small grains is discussed.

Chickpea (Cicer arietinum L.) seed is a potential source of protein ingredients with desirable nutritional and functional properties. Knowledge of molecular characteristics of a food protein is essential before a protein can gain widespread use as a food ingredient. The objectives of this study were to prepare chickpea proteins using different extraction methods and precipitation methods and to investigate molecular characteristics using polyacrylamide gel electrophoresis (PAGE; Native and SDS), reversed phase high performance liquid chromatography (RP-HPLC) and electrospray ionization mass spectrometry (ESI-MS) techniques. Proteins of ground chickpea seed were extracted with sodium hydroxide (NaOH) and with citric acid solutions and precipitated with addition of acid and by cryoprecipitation. The protein contents of the protein preparation ranged from 49% to 97%. The microstructures of chickpea protein isolates examined by scanning electron microscope (SEM) revealed the presence of starch grains in the cryoprecipitates from citric acid extraction but not in isoelectric precipitates. The globulins (legumins and vicilins), glutelins, and albumins from both citric acid and NaOH isolates were characterized by Native-PAGE. The cryoprecipitates contained mainly the globulin-rich proteins. With SDS-PAGE characterization, protein subunits were identified as follows: (i) legumin subunits: MW 40, 39, 26, 23, and 22 kDa, (ii) vicilin subunits: MW 50, 37, 33, 19, and 15 kDa, (iii) glutelin subunits: 58, 55, and 54 kDa, and (iv) albumin subunits: 10 kDa. Separation of fractions of isolated chickpea proteins by RP-HPLC showed that early eluting fractions (Rt 20-30 min) consisted of subunits of MW 6.5-31 kDa (SDS-PAGE). At elution time 30-36 min, the fractions obtained were composed mainly of mixtures of legumin and vicilin subunits (MW 14-45 kDa). The major subunits of chickpea protein fractions from both cryoprecipitates and isoelectric precipitates are legumin basic subunit (MW&sim;23 kDa) and vicilin-rich proteins (MW&sim;19, 17, 15 kDa). ESI-MS analysis of fractions separated by RP-HPLC showed MW ranging between 5.1 and 53.5 kDa. The subunits of MW 35366, 27626, 22864, 20531, 16092, and 15626 Da of fractions from ESI-MS corresponded to MW 35.3, 28.0, 24.1, 20.5, 16.1, and 15.3 kDa identified in SDS-PAGE. These fractions were identified as legumin-rich and vicilin-rich proteins.

To investigate vascular-plant phylogeny at deep levels of relationship, I collected and analyzed a large set of plastid-DNA data comprising multiple protein-coding genes and associated noncoding regions. I addressed questions relating to overall tracheophyte phylogeny, including relationships among the five living lineages of seed plants, and within two of the largest living gymnosperm clades (conifers and cycads). I also examined relationships within and among the major lineages of monilophytes (ferns and relatives), including their relationship to the remaining vascular plants. Overall, I recovered three well-supported lineages of vascular plants: lycophytes, monilophytes, and seed plants. I inferred strong support for most of the phylogenetic backbones of cycads and conifers. My results suggest that the cycad family Stangeriaceae (Stangeria and Bowenia) is not monophyletic, and that Stangeria is instead more closely related to Zamia and Ceratozamia. Within the conifers, I found Pinaceae to be the sister-group of all other conifers, and I argue that two conifer genera, Cephalotaxus and Phyllocladus (often treated as monogeneric families) should be recognized under Taxaceae and Podocarpaceae, respectively. Systematic error likely affects inference of the placement of Gnetales within seed-plant phylogeny. As a result, the question of the relationships among the five living seed-plant groups still remains largely unresolved, even though removal of the most rapidly evolving characters appears to reduce systematic error. Phylogenetic analyses that included these rapidly evolving characters often led to the misinference of the “Gnetales-sister” hypothesis (Gnetales as the sister-group of all other seed plants), especially when maximum parsimony was the inference method. Filtering of rapidly evolving characters had little effect on inference of higher-order relationships within conifers and monilophytes, and generally resulted in reduced support for backbone relationships. Within the monilophytes, I found strong support for the majority of relationships along the backbone. These were generally congruent with other recent studies. Equisetaceae and Marattiaceae may be, respectively, the sister-groups of the remaining monilophytes and of the leptosporangiate ferns, but relationships among the major monilophyte lineages are sensitive to the outgroups used, and to long branches in lycophytes.

INDETERMINATE DOMAIN (IDD) genes encode a large family of putative transcription factors characterized by four different zinc finger motifs in a conserved arrangement. In Arabidopsis thaliana there are 16 IDD genes designated AtIDD1-AtIDD16. Microarray database expression resources show that AtIDD1 transcripts are present at high levels in dry seed and in response to abscisic acid. Transcripts present in dry seed at high levels have previously been shown to play roles in later stages of seed development or as provisions necessary for the resumption of metabolic activity following seed dormancy. Here I show that lines with constitutive expression of AtIDD1 have decreased and increased sensitivity to the phytohormones abscisic acid and gibberellic acid, respectively, when applied exogenously. Additionally, plants overexpressing AtIDD1 have altered mucilage extrusion and seed coat morphology. Altered seed coat morphology was also observed In constitutive AtIDD1 knock down lines. Therefore, these phenotypes could indicate that AtIDD1 plays a regulatory role in seeds during seed development and/or germination.

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