<p>Speciation is a constantly ongoing process whereby reproductive isolating baririer build up over time until groups of organisms can no longer exchange genes with each other. Adaptation is thought to play a major role in the formation of these barriers, although the genetic mechanisms and geographic mode underlying the spread of barriers due to adaptive evolution is poorly understood. Critically, speciation may occur in stages through the formation of intermediate partially reproductively isolated groups. The idea of such widespread ecotypes has been the subject of great controversy over the last century. Even so, we have relatively little understanding about whether widespread ecotypes exist, wheather they are reproductively isolated, and how adaptive alleles are distributed among partially isolated groups. In this dissertation, I examined these issues in widespread coastal perennial and inland annual ecotypes of the yellow monkeyflower, Mimulus guttatus. First, I determined that coastal and inland populations comprise distinct ecotypic groups. I then determined that these ecotypes are adapted to their respective habitats through genetically based flowering time and salt tolerance differences. I assessed the genetic architecture of these adaptations through quantitative trait loci (QTL) analysis and determined the geographic distribution of the underlying alleles through latitudinally replicated mapping populations. I quantified the contribution of these loci to adaptation in the field through the incorporation of advance generation hybrids in reciprocal transplant experiments. In the process, I discovered a widespread chromosomal inversion to be involved in the adaptive flowering time and annual/perennial life-history shift among the ecotypes. Overall, the results of this study suggest that widespread reproductively isolated ecotypes can form through the spread adaptive standing genetic variation between habitats and that chromosomal rearrangements can integral to this process.</p> / Dissertation

Influence of absicisic acid on flowering in Phalaenopsis hybrida Abscisic acid (ABA) in the buds (or flowering shoots) , leaves and roots of Phalaenopsis hybrida (cv. TS 340) was identified and quantified by gas chromatography-mass spectrometry- selected ion monitoring using hexadeuterated ABA as an internal standard. Leaves contained much lower levels of both free and bound ABA than did roots. Dormant buds contained a relatively higher level of free ABA, whereas no detectable free or bound ABA was found in flowering shoots either at a length of 2 to 3 cm or 7 to 10 cm. Dormant stage P. hybrida ( grown at 28¢J ), levels of free ABA in the roots were higher than those in plants with flowering shoots, the levels of bound ABA in roots exhibited opposite tendency. Free and bound ABA in leaves was slightly increased in plants with flowering shoots as compared to those in the dormant stage. In addition, exogenous ABA application at 0.1 or 1 &#x00B5;g per plant inhibited initiation of flowering shoots, especially at 1&#x00B5;g per plant. These results suggest the decrease in the free ABA contents in the roots and buds, but not in the leaves, is correlated with bud activation and development of flowering shoots. Protein synthesis and flowering in Doritis pulcherrima in relation to daylength Mature doritis plants (Doritis pulcherrima Lindley cv. S84 -3345) were cultured in plastic pots with 9-h (short-day, SD) and 16-h (long-day, LD) photoperiods, respectively. The main 9-h light period was under field conditions (30 ¢J day/20 ¢J night on average). The supplemental 7-h light conditions for the LD was in chambers with 14 £gmol. m-2 s-1 photosynthetic photon flux. When transferred to SD for 30 or 40 days the plants initiated flower spikes (90 % of the total plants) between 2.0 to 3.0 cm and 7.0 to 10.0 cm in length, respectively. In contrast, only 10 % of the plants producing flowering shoots were observed under LD conditions. Unique 21 and 103 kDa proteins were evident in one-dimensional electrophoresis of proteins from mature leaves under SD conditions. Two-dimensional gel electrophoresis confirmed that clear polypeptide spots with a molecular mass of 21 kDa at isoelectric point of 5.2 and 103 kDa at isoelectric point of 5.6 accumulated in leaves when flowering shoot reached 7.0 to 10.0 cm (4 to 5 flowe4 primordia apparent). Possibly, the 21 and 103 kDa proteins play the important role during initiation of flowering shoot in doritis. Polypeptide sequencing of P21 suggested a possible relationship to the product of cell division-like protein in Arabidopsis thaliana. It is clear that doritis is a facultative SD plant, and photoperiodic induction of its flowering is closely associated with changes of protein synthesis in its leaves.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(農学) / 甲第19051号 / 農博第2129号 / 新制||農||1033 / 32002 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 准教授 中﨑 鉄也 / 学位規則第4条第1項該当

Studies of demography and population structure give insight into important evolutionary processes such as speciation and diversification. In the present work I perform such studies in the genus Capsella, which has three species: C. grandiflora, an outcrossing diploid, C. rubella a selfing diploid, and C. bursa-pastoris a selfing tetraploid. These three species make a good model system for evolutionary studies because they encompass two major plant evolutionary processes: mating system shifts and polyploidization. To conduct my studies I have gathered a large number of samples across the distributions of each species and scored them both phenotypically and genotypically: more specifically we measured flowering time and collected DNA sequence data. In the tetraploid C. bursa-pastoris we applied an association mapping approach which takes population structure into account to search for genetic variation associated with variation in flowering time. Flowering time is an important and highly adaptive trait which is frequently subject to natural selection. We found evidence of association between flowering time and several single nucleotide polymorphisms (SNPs) within the flowering locus C (FLC) and cryptochrome 1 (CRY1). In the case of FLC these SNPs code for nonconsensus splice site variation in one of the two copies of the gene. The SNPs could potentially have functional consequences and our results imply that non-functionalization of duplicate genes could be an important source of phenotypic variation. Using a novel coalescent based approach, we investigated the polyploid origin of C. bursa-pastoris and find evidence supporting a recent autopolyploid origin of this species. In the two diploid species, I use sequence data to investigate population structure and demographic history and to assess the effects of selfing on C. rubella. Observed patterns of population structure and genetic diversity in C. rubella can be explained by a combination of both demographic history and mating system. Observed patterns in C. grandiflora suggest that the investigated populations do not deviate strongly from the SNM, which has rarely been found in modern demographic studies. Finally, we investigate the effect of sampling strategy on demographic inference. Extensive sampling both within and across our populations allow us to empirically test the effect of sampling strategy on demographic inference. We complement the empirical analysis with simulations and conclude that the effect of sampling strategy is in many cases weak compared with that of demographic events. Nevertheless, these effects are real and have the potential to lead to false inference and therefore sampling strategy should be carefully considered in demographic studies. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 725

A study of factors contributing to successful controlled pollinations of Pinus patula Scheide et Deppe was undertaken. The pollen morphology of P. patula, P. oocarpa, P. greggii, P. elliottii, P. tecunumanii, P. caribaea and P. radiata was studied and the mean size of pollen grains was determined for these species. Clonal differences in pollen size within P. patula were also determined. The impact of pollen management practices on pollen viability was highlighted and a protocol for in vitro pollen viability testing of P. patula and other pine species was determined. A one percent agar solidified distilled water medium gave the best germination results after 72 hours incubation at 30 °C for a number of different Pinus species and P. patula clones. The addition of boric acid increase germination, although not significantly. The addition of sucrose to the pollen germination medium had a negative effect on pollen germination of P. patula, P. greggii and P. caribaea. Re-hydration of pollen for two hours prior to in vitro germination testing improved germination significantly. Incubation temperatures of above 38 °C were detrimental to germinating pollen grains. Stored pollen with low humidity (less than 10 %) of P. patula, P. greggii and P. caribaea could tolerate temperatures of up to 70 °C while still retaining some level of viability. The initiation and growth of the pollen tube was also studied and differences in pollen tube-lengths germinated at 30 °C for 72 hours were found between species studied. Flowering of different P. patula clones was monitored over seven seasons. Flowering periods varied in length between 4 and 14 days amongst five clones over the different seasons. The best cone-survival after controlled pollination was achieved with breathable micro-fibre material. Seed yields were also highest when breathable material was used for controlled pollination. The role of pollen viability in controlled pollination was also determined in pollination studies with low viability resulting in low cone survival and low seed yields. The temperature and relative humidity inside isolation bags were monitored and temperatures above 40 °C were reached inside bags constructed of nonbreathable material. These temperatures were lethal to pollen germinating in vitro. Relative humidity of between 80 and 100 % was maintained in non-breathable bagging material, constituting a risk of diseases causing cone-mortality. The application of fungicide before, during and after controlled pollination was ineffective in improving cone survival. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2002.

Kiekvienais metais, augalams žydint, išbyra žiedadulkių. Augalai skirtingu metu subrandina žiedadulkes, tačiau ir tos paties rūšies žiedadulkėms būdingi fiksavimo kitimai. Žiedadulkių sklaidos tyrimams yra svarbūs ir fitofenologiniai duomenys, todėl detali šių duomenų analizė yra būtina atliekant žiedadulkių kiekių, sezonų trukmės įvertinimus. / Every year, when plants bloom some pollen is spread. Plants mature a different quantity of pollen in different time, though fixing changes are typical even to the pollen of the same species. Phytophenological data is also important to the investigation of the pollen dispersion., thus the detailed analysis of this data is essential for the evaluation of the pollen quantity and duration of the seasons.

No description available.

In this thesis, I combine molecular analyses, common-garden and field experiments to examine how evolutionary and ecological processes influence patterns of genetic variation among and within populations of the declining, insect-pollinated, self-incompatible, perennial herb Primula farinosa. More specifically I examined 1) whether genetic diversity at neutral marker loci was related to habitat fragmentation and habitat stability, 2) whether floral display and flowering time were more strongly differentiated among populations than were putatively neutral marker loci, 3) whether adaptive population differentiation could be detected on a local spatial scale, and 4) whether floral display differentially affected male and female reproductive success. Genetic diversity at neutral marker loci was lower within fragmented populations on the Swedish mainland than within the more densely occurring populations on the island Öland, SE Sweden. On Öland, fluctuations in population size were more pronounced on thin than on deep soils, but genetic diversity was not related to soil depth. Among-population genetic differentiation in scape length and flowering time was stronger than that of neutral marker loci, which is consistent with divergent selection acting on these traits. Water availability should influence the length of the growing season and thus the time available for fruit maturation, but flowering time in a common-garden experiment was not related to estimates of water availability at sites of origin. In a reciprocal transplant experiment conducted among four populations separated by up to a few kilometres and growing in environment differing in water availability and grazing intensity, no evidence of local adaption was observed. Finally, in a field experiment, interactions with pollinators and antagonists differentially affected selection on floral display through male and female function. Taken together, the results indicate that habitat connectivity and environmental heterogeneity contribute to high neutral and adaptive genetic variation in Primula farinosa on the island Öland, SE Sweden, and illustrate that effects on both male and female reproductive success need to be considered to understand fully the evolution of floral display.

Flowering in Arabidopsis thalina is controlled by multiple pathways and is repressed by cold. To understand how A. thalina molecularly responds to cold stress temperatures, we subjected seedlings to different temperatures of cold stress for four days. Specifically, we conducted quantitative PCR of CONSTANS (CO) and the F-Box protein FKF1 to observe specifically how cold temperatures might affect the flowering time of a plant. We found a 16°C cold stress temperature increased both CO and FKF1 transcription when compared to a 24°C control. The increased expression of both CO and FKF1 may serve as a priming pathway that enables plants to be ready to flower at the precise moment when spring arrives.

Copies of author's previously published articles inserted. / Bibliography: leaves 143-167. / xvi, 176 leaves, [17] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Temperature may affect fruit-set in grapevines through its effect on the development of the flowers up to flower opening and on pollination, be it on the germination of the pollen and the growth of the pollen tube, or on the post-fertilisation growth of the ovule. / Thesis (Ph.D.)--University of Adelaide, Dept. of Horticulture, Viticulture and Oenology, 1996