Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 83-92).

The onset of reproduction is an important trait and is controlled by the FT1 locus in poplar (Populus sp.). Sequence variation in this locus is not well-understood. This study's aim is to identify sequence variation in the FT1 locus in a small population of Populus deltoides with varying reproductive onset. Gene specific primers were designed to amplify FT from 14 genotypes. The sequence analysis showed 12 single nucleotide polymorphisms and four insertion-deletion sites located in introns of FT1. No connection was observed between the identified polymorphisms and variation in reproductive onset. Further DNA sequencing of the genotypes needs to be done on the promoter region of FT1 to conduct an association study to statistically assess the connection between polymorphisms and phenotypic variation in a larger population. This information is expected to help us understand the genetic basis of phenotypic variation in reproductive onset.

Darbo objektas – Populus genties medžiai: Populus alba × Populus tremula (Nr. 20), Populus tremula x Populus alba ( Nr.21), P. tremuloides x P. tremula (Nr.8), P. tremuloides x P. tremula (Nr.3), P. tremuloides x P. tremula (Nr.9), Populus alba (Š16), P. berolinensis. Darbo tikslas – nustatyti tuopų genties medžių hibridų mikrodauginimo in vitro sąlygas, bei augalų- regenerantų išauginimą. Išskirti genominę DNR iš drebulių, naudojant genominės DNR išskyrimo rinkinį NucleoSpin Plant. Darbo metodai - Eksplantų paruošimas sterilinimui ir sterilinimas. Augalų regenerantų kultivavimo sąlygos. Maitinamosios terpės ruošimas, sterilinimas ir sudėtis. Mikroūglių perkėlimas į nesterilias sąlygas. DNR išskyrimas. Darbo rezultatai. Tuopų medžių eksplantų sterilinimui tikslinga naudoti aseptinių tirpalų kombinaciją be „ACE“, kad užtikrinti gyvybingų ir be užkrato eksplantų išlikimą. Grybine infekcija labiausiai užkrėsti berlyninės tuopos eksplantai: užkratas sudarė nuo 72 proc. iki 80 proc. priklausomai nuo eksplantų prigimties. Tuopų genties medžių genotipas turi įtakos morfogenezei audinių kultūroje. Geriausia maitinamoji terpė mikroūglų susidarymui yra Murashige Scoog (MS) su citokininu BA- 0,5 mg/l. Kaliaus susidarymas ir spalva priklauso nuo genotipo. Iš visų tuopų hibridų sparčiausiai augo hibridas Nr. 8 P.( tremuloides x P. tremula). Vidutinis jo augimo greitis- 8,3 mm per 10 dienų. Atlikti DNR tyrimai APPD metodu parodo, kad motinmedžiai ir išauginti augalai in vitro yra... [toliau žr. visą tekstą] / Aim of the work: Genus Populus trees: Populus alba × Populus tremula (Nr. 20), Populus tremula x Populus alba (Nr.21), P. tremuloides x P. tremula (Nr.8), P. tremuloides x P. tremula (Nr.3), P. tremuloides x P. tremula (Nr.9), Populus alba (Š16), P. berolinensis. Object of the work: Investigate poplar genus hybrids in vitro micro reproduction conditions and regenerate plants growth. Investigate poplar genomic DNA using NucleoSpin Plant Kit. Methods: Preparation of explants culture for sterile manner. Plants regenerate rear conditions. Growth media preparation and sterilization. Micro sprout input into unsterile conditions. DNA isolation. Results: For poplar trees explants sterilization is purposeful using aseptic solution combination without “ACE”, to vouch vital and half explants survival. Fungous infection found in berolinensis poplar explants: infections reach from 72 to 80 % depending from explants nature. Poplar genus genotype has impact on morphogenesis in tissue culture. The best growth media is Murashige Scoog (MS) with citotoksine BA- 0,5 mg/l. Callus formation and colaration depends on genotipe. Fastest growth had hybrid No. 8 ( tremuloides x P. tremula) from all poplar hybrids. His mean growth was 8.3 mm per 10 days. RAPD analysis shown that the parent trees and trees race in vitro are the similar (the same).

Proanthocyanidins (PAs), also known as condensed tannins (CTs), are oligomers or polymers of flavan-3-ols. They have a very important role in plant-environment interactions, such as defense against herbivory and pathogens. They may also be important for light stress tolerance. In poplar, PAs can make up as much as 30% of the leaf dry weight. The synthesis of PAs in poplar was demonstrated to be inducible by both abiotic and biotic stresses. The B-ring hydroxylation pattern of flavan-3-ols directly affects the structure of PAs, and many studies have shown that B-ring hydroxylation of PAs is associated with their biological functions, including effects on leaf litter decomposition rate and anti-herbivore activity. Anthocyanins are very important colour pigments in plants, and share the intermediate leucoanthocyanidin with PAs. The role of anthocyanins in plant pollination, light stress tolerance, and seed dispersal has been well studied. A change in B-ring hydroxylation pattern can modify the colour of anthocyanins dramatically and also change their biological function. Flavonoid 3’-hydroxylase and flavonoid 3’, 5’-hydroxylase (F3’H and F3’5’H) are the two enzymes involved in determining the B-ring hydroxylation pattern of both PAs and anthocyanins. The objective of this study is to characterize the possible role of flavonoid 3’, 5’-hydroxylase in PA and anthocyanin biosynthesis in poplar. A candidate F3’5’H was identified in the Populus trichocarpa genome database based on previous expression profile experiments, and called PtF3’5’H1. The predicted protein shares high sequence similarity with previously characterized F3’5’H proteins from other plants. To test the function of PtF3’5’H1 directly, transgenic hybrid poplar plants overexpressing PtF3’5’H1 were generated. Preliminary LC-MS analysis showed that the hydroxylation pattern of the PA in the transgenic poplars was not significantly modified. Likewise, overexpression of PtF3’5’H1 in poplar did not change the overall amount of PAs. These results suggest that overexpression of PtF3’5’H1 in poplar is not sufficient to modify the B-ring hydroxylation pattern of PA, and that additional factors may be required. By contrast, the transgenic PtF3’5’H1 overexpressing poplar did show an alteration in anthocyanin profile. In leaves of transgenic poplars, several putative delphinidin derivatives were observed at greater levels than in the wild type, indicating that PtF3’5’H1 participates in the anthocyanin production in poplar. However, transiently introducing PtF3’5’H1 into Nicotiana benthamiana had no effect on the anthocyanin profile in this plant. I conclude that PtF3’5’H1 is very likely to be involved in the anthocyanin synthesis in poplar, while the function of PtF3’5’H1 in poplar PA synthesis has yet to be demonstrated. / Graduate

Revegetation of riparian tree species along the lower Colorado River is currently a major activity for federal and state agencies. Revegetation methods for Fremont cottonwood (Populus fremontii), Goodding's willow (Salix gooddingii), and coyote willow (S. exigua) have historically consisted of cutting collection and vegetative propagation. If direct seeding could be implemented, large cost-savings could be realized while enhancing restoration results due to increased genetic and structural diversity. The following documents laboratory, greenhouse, and field studies conducted to establish seed storage practices, irrigation techniques, and seeding methods and rates which maximize germination and growth rates of these riparian tree species. Experimental seed storage study results indicated that seed viability was maintained for at least a two-year window by freezing, during which seed can be utilized for direct seeding or seedling production. Greenhouse study results include: (1) seed cleaning resulted in higher tree establishment; (2) adverse soil conditions reduced growth rates; (3) organic fertilizer amendment mitigated negative effects of sandy soil for Fremont cottonwood but not for willow; (4) mixed seeding resulted in cottonwood dominance, indicating that reduced rates or separate seeding of this species might be required to improve success of willow species seeding. Small-scale field study results include the following: (1) Fremont cottonwood establishment averaged 7% of pure live seed rates, whereas willow species establishment was less than 1%; (2) sprinkler irrigation did not affect establishment, and decreased tree growth rates; (3) hydroseeding resulted in higher canopy cover, establishment, and above-ground biomass compared to broadcast seeding for all three species; (4) furrow or border irrigation did not affect Fremont cottonwood or coyote willow establishment, but furrow irrigation resulted in higher Goodding's willow establishment. Volunteer species were abundant, with grasses dominating cover and biomass after one growing season despite application of grass specific herbicide. Saltcedar (Tamarix ramosissima) also established in abundance, but grew slower than Fremont cottonwood during the first growing season. Monitoring after three growing seasons indicated higher growth rates and survival of Fremont cottonwood compared to volunteer species. Larger-scale seeding studies are required to refine establishment rates and determine the cost-effectiveness of direct seeding for large-scale Salicaceae species revegetation.

Condensed tannins or proanthocyanidins (CTs) are polymeric flavonoids and common plant secondary metabolites. They are defined by their protein binding capacity, and anti-oxidant and metal chelating properties. Known functions of CTs include anti-herbivore and anti-microbial defenses. Chemical ecology studies, especially on CTs, have focussed almost exclusively on foliar chemistry and above-ground ecological interactions. However, CT concentrations in roots can match and far exceed those found in leaves, particularly in woody plant species. This suggests that CTs are also likely to have important ecological and physiological roles below-ground. A review of the literature suggests three potential roles of root CTs: 1) defense against soil pathogens and root herbivores; 2) facilitating adaptation to toxic soils through heavy metal chelation, and; 3) facilitating or modulating nutrient uptake through the binding of nutrient cations. In this thesis the relationship between root CTs and nutrient uptake will be analysed in P. tremula x alba. Localization of CTs was determined through both quantitative and histochemical techniques. Quantitation of CTs with the 1-butanol:HCl assay clearly showed that CT concentration was higher in the white root zone compared to the brown root zone or cork zone. This is inconsistent with the term ‘condensed tannin zone’ that is commonly used to describe the macroscopic brown zone of the root between the white zone and the cork zone in Pinus. The tissue specific localization of CTs in roots was determined using the CT-specific stain, 4-dimethylaminocinnamaldehyde (4-DMACA), on embedded longitudinal and fresh cross sections. These stained sections showed that CTs were present in cells on the root surface, specifically accumulating in the root cap and epidermal cells. CTs were also sporadically present in the cortical cells of the young, white root zones. CT concentration declined as distance from the root tip increased. The pattern of CT distribution, as indicated by intensity of the staining, corresponded directly to the quantitative assay results. Growing poplars under low nitrogen availability stimulated higher root CT concentrations than when they were grown under high nitrogen availability, suggesting a link between nitrogen and CTs. Since CTs are known to bind cations in vivo, I hypothesized that root CTs may modulate or facilitate nutrient uptake by binding positively charged nutrient ions. The Microelectrode Ion Flux Measurement (MIFE) technique was used to analyse specific fluxes of NH4+, NO3- and Ca2+ at specific root locations in poplar roots, and test for spatial correlation with CT localization. This technique was also used to compare the NH4+, NO3- and Ca2+ fluxes in transgenic high-CT and wild-type lines of Populus tremula x alba to test the impact of CTs on nutrient uptake directly. No correlation was found between fluxes of NH4+, NO3- or Ca2+ and CT distribution. The data indicate that root CTs do not influence nutrient uptake in Populus. This study provides data regarding the pattern of CT distribution as well as fundamental information on nutrient uptake in P. tremula x alba roots. It provides new knowledge that will be used to stimulate investigations on other potential roles of root CTs. / Graduate

Species interactions are recognised as an important evolutionary process, with foundation species in particular being of exceptional importance. Foundation species are those species exhibiting dynamic physical traits, under strong genetic control, that shape the natural processes of habitats and ecosystems. These traits lead to extended consequences for the associated organisms in their community. Therefore, intra-specific variation of a foundation species can have important evolutionary consequences for habitats, communities and entire ecosystems. One such foundation species is aspen (Populus tremula L.), which has important conservation value, particularly for the high diversity of associated species. In Scotland aspen exists in fragmented clonal patches, but has been found to contain a high diversity of associated organisms some of which have a UK Biodiversity Action Plan (BAP). One such group of organisms of high diversity and conservation value in Scotland are the epiphytic cryptogams (i.e. mosses, liverworts, lichens). To date more than 300 species have been recorded on aspen in Scotland, comprising approximately 40% of the epiphyte flora of Europe. The research presented here uses a combination of natural aspen system and two aspen common gardens to test the effects of aspen genetic diversity on physical traits potentially important for epiphyte diversity. The traits investigated were bark texture and bark phenolic chemistry. Bark texture in the wild clones was found vary significantly between clones and under strong genetic control (up to 40%). Bark phenolic chemistry also showed significant genotypic variation, but could not be correlated with patterns of epiphyte species richness and diversity. Nevertheless, epiphytes showed significant patterns related to aspen genotype, particularly along a gradient of bark texture. The results indicate that epiphyte communities are part of the ‘extended phenotype’ of native aspen populations in Scotland are very important for maintaining current levels of epiphyte diversity. A greater diversity and abundance of aspen genotypes in the landscape are essential for increasing epiphyte species richness and diversity, and for ecosystem health as a whole.

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