Several wheat characters have been shown to exhibit rather complicated inheritance. Examples are such characters as cola length, spike density, and awn classes. This paper reports a study of the inheritance and of the correlated inheritance of these and some other plant characters in a cross between a hybrid of Dicklow X Sevier (III C 18) with Federation.

Throughout much of western United States the soils contain considerable calcium carbonate. This lime is either distributed throughout the soils profile or it occurs in a zone of accumulation at varying depths. On many of these soils certain plants exhibit a chlorosis in varying intensity. This chlorotic condition is not stable as it varies from year to year and even day to day with changing conditions of climate and soil. this chlorosis has been reported from the wine and fruit regions of Europe, from the pineapple and sugar cane areas of Puerto Rico and Florida, from the sorghum and bean areas of the Great Plains and Southwest. The variety of plants subject to lime-induced chlorosis is great and varied. It includes such diverse species as citrus fruits, deciduous fruits, conifers, grapes, strawberries, raspberries, pineapple, sugar cane, sorghum, peas and beans. Also many flowers, shrubs and ornamental tress are affected. The economic importance of the disease is evident. Because addition of iron salts to the diseased foliage is known to correct the chlorosis, and because analysis of diseased tissue has failed to prove iron to be deficient, it will be the purpose of this study to investigate the iron content of plants in relation to the disease. An explanation for the observed relationships of iron to the disease will be sought.

No description available.

"June 2002" / Bibliography: leaves 172-198. / viii, 198 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Proposes that the overall outcome of plant interactions along a temporal gradient of resource availability changes from positive during interpulses to negative during pulses. Examines negative interactions between 4 co-dominant chenopod scrubs in arid Acacia papyrocarpa woodlands. Negative interactions were more intense when conditions were least productive. Positive interactions between seedlings also changed over time, depending on the facilitation mechanism. Plant interactions seem to be most intense at the beginning of interpulses when plants are competing for diminishing water, or survivorship is enhanced in the favorable microsites provided by other plants. Later in the interpulse, interactions become less intense as conditions become more stressful and therefore survivorship and growth are affected more by abiotic conditions than plant interactions. / Thesis (Ph.D.)--University of Adelaide, Dept. of Environmental Biology, 2002

<p>Six methods are used for clustering data containing two different objects: sugar-beet plants </p><p>and weed. These objects are described by 19 different features, i.e. shape and color features. </p><p>There is also information about the distance between sugar-beet plants that is used for </p><p>labeling clusters. The methods that are evaluated: k-means, k-medoids, hierarchical clustering, </p><p>competitive learning, self-organizing maps and fuzzy c-means. After using the methods on </p><p>plant data, clusters are formed. The clusters are labeled with three different proposed </p><p>methods: expert, database and context method. Expert method is using a human for giving </p><p>initial cluster centers that are labeled. The database method is using a database as an expert </p><p>that provides initial cluster centers. The context method is using information about the </p><p>environment, which is the distance between sugar-beet plants, for labeling the clusters. </p><p> </p><p>The algorithms that were tested, with the lowest achieved corresponding error, are: k-means </p><p>(3.3%), k-medoids (3.8%), hierarchical clustering (5.3%), competitive learning (6.8%), self- </p><p>organizing maps (4.9%) and fuzzy c-means (7.9%). Three different datasets were used and the </p><p>lowest error on dataset0 is 3.3%, compared to supervised learning methods where it is 3%. </p><p>For dataset1 the error is 18.7% and for dataset2 it is 5.8%. Compared to supervised methods, </p><p>the error on dataset1 is 11% and for dataset2 it is 5.1%. The high error rate on dataset1 is due </p><p>to the samples are not very well separated in different clusters. The features from dataset1 are </p><p>extracted from lower resolution on images than the other datasets, and another difference </p><p>between the datasets are the sugar-beet plants that are in different growth stages. </p><p> </p><p>The performance of the three methods for labeling clusters is: expert method (6.8% as the </p><p>lowest error achieved), database method (3.7%) and context method (6.8%). These results </p><p>show the clustering results by competitive learning where the real error is 6.8%. </p><p> </p><p>Unsupervised-learning methods for clustering can very well be used for plant identification. </p><p>Because the samples are not classified, an automatic labeling technique must be used if plants </p><p>are to be identified. The three proposed techniques can be used for automatic labeling of </p><p>plants.</p>

<p>This work describes the regulation of drought stress responses in <i>Arabidopsis thaliana</i> and adresses the roles of the homeodomain-leucine zipper (HD-Zip) transcription factors in this regulation. The characteristics of <i>ATHB6</i> and <i>ATHB7</i>, two genes encoding class I HD-Zip transcription factors were analysed. </p><p>Expression of <i>ATHB6</i> and <i>ATHB7</i> was transcriptionally activated in plants subjected to water deficit or exogenous treatment with abscisic acid (ABA).</p><p>Transgenic plants constitutively expressing the <i>ATHB7</i> gene displayed a delayed elongation growth of the main inflorescence stem after transition to reproductive development. This phenotype is consistent with ATHB7 acting as a negative regulator of growth and development of the elongating stem in response to water availability.</p><p>Transgenic <i>abi1-1</i> mutant plants constitutively expressing the <i>ATHB7</i> gene displayed a reduced wiltiness as compared to monogenic <i>abi1-1</i> mutants. These data are consistent with the ATHB7 protein having a central role in the drought stress response, regulating the water balance of the plant, and acting downstream to <i>ABI1</i>. Furthermore, the data is consistent with ATHB7 acting as a positive regulator of the drought stress response.</p><p>The ABA-induced expression of the <i>ATHB7</i> gene displayed a dependence on the phytochrome system, suggesting an interplay between light and osmotic stress signaling in the regulation of the <i>ATHB7</i> gene.</p>

<p>The evolutionary relationships between the angiosperm floral organs and the reproductive organs of other seed plants is not known. Flower organ development requires transcription factors encoded by the MADS-box genes. Since the evolution of novel morphology likely involve changes in developmental regulators, I have analysed MADS-box genes from the conifer Norway spruce, <i>Picea abies</i>, a representative of the gymnosperm group of seed plants.</p><p>The results show that the MADS-box gene family has evolved via gene duplications and subsequent diversifications in correlation in time with the evolution of morphological novelties along the seed-plant lineage.</p><p>Angiosperm MADS-box genes that determine petal and stamen development have homologues in the conifers, that are specifically active in pollen cones. It is, therefore, likely that the common ancestor of these genes controlled the development of the pollen-bearing organs in the early seed plants, and later were recruited for petal development in the angiosperms.</p><p>Norway spruce set cones at an age of 15-20 years. One of the spruce MADS-box genes analysed may have a function in the control of the transition to reproductive phase, supported by expression data and the effect of the gene on development of transgenic <i>Arabidopsis</i> plants.</p><p>Two of the spruce genes identified are not closely related to any known angiosperm gene. These may have roles in gymnosperm-specific developmental processes, possibly in the patterning of the conifer cones, as suggested by their expression patterns.</p><p>The molecular regulation of cone- and flower development in fundamental aspects is highly conserved between conifers and angiosperms, however, differences detected may be informative regarding the origin of morphological complexity.</p>

The purpose of this study was to examine the molecular evolution of floral developmental MADS-box genes in diploid and allotetraploid cotton (Gossypium, Malvaceae). We isolated and characterized both cDNA and genomic DNA sequences of four MADS-box genes, B-sister, APETALA3 (AP3), PISTILLATA (PI, two copies) and AGAMOUS (AG), in seven Gossypium species (2 A-genome species, 2 D-genome species, 1 C-genome species and 2 AD-genome species) as well as an outgroup species, Gossypioides kirkii. We then studied the expression patterns of each gene by reverse-transcriptase PCR (RT-PCR) in each flower part for different flower stages of G. arboreum (A-genome), G. raimondii (D-genome) and G. hirsutum (AD-genome). We found that these MADS-box genes are evolving independently at the DNA sequence level but exhibit highly variable expression patterns in allotetraploid G. hirsutum. These MADS-box genes contain highly conserved exon lengths and exon/intron structures, high nucleotide identity with homologs in Arabidopsis thaliana and Antirrhinum majus, and conserved gene phylogeny within the genus Gossypium. All the genes exhibit evidence of codon bias. The AP3 gene in Gossypium appears to be subject to positive selection, while the PI-small copy of the PI gene appears to be subject to strong functional constraints together with a very low mutation rate. Within G. hirsutum, the B-sister gene exhibits gene silencing of the A-subgenomic homoeolog and the PI-big copy of the PI gene has experienced pseudogenization by insertion of a copia-like retroelement. The AP3, PI-small and AG genes show biased expression patterns in G. hirsutum. These MADS-box genes also demonstrated developmentally regulated expression patterns in G. arboreum, G. raimondii and G. hirsutum.

Thesis (Ph. D.)--University of Chicago, Dept. of Ecology and Evolution, August 1999. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.