The vast majority of flowering plants rely on pollinators for outcrossed reproduction. Unfortunately, many species of pollinators are in decline. Pollinators face a number of challenges, including shifting land use, climate change and pesticides. In addition, pollinator habitat may be altered or eliminated through urbanization. Fragmented urban landscapes may lengthen the distances among foraging patches, limit resources in a given patch, and reduce the availability of pollinator nesting sites. Here, I examine the effects of urbanization on pollination services by addressing the following questions: (1) Does bee species richness and/or abundance change along an urbanization gradient?; (2) Does the pollen limitation of a focal species vary along the same gradient?; (3) Do plants with a mixed mating system produce more selfed seeds in more urban environments? Using the percentage of impervious land cover in the space immediately surrounding the site as a proxy for site urbanization, 15 study sites were set up across the city of Ottawa to span a range from minimal percent impervious surface (mostly green space) to mostly impervious surface (little green space) at a range of spatial scales. At each site I set up an array of 20 potted Impatiens capensis plants as well as six pan traps in order to collect data on pollen limitation, seed production, and the number of selfed progeny, in addition to information about local pollinator species richness and abundance. Plants in the arrays were randomly assigned to either a hand or open pollination treatment in order to assess the level of pollen limitation. Surprisingly, pollinator species richness and abundance were not correlated with urbanization. Pollen limitation declined with urbanization, however, so did overall seed set, making it difficult to detangle the effects of resource limitation and hand pollination treatments. The number of selfed seeds produced by a plant was also significantly correlated with site urbanization. Further investigation is required to better understand the dynamics of pollination services in urban environments. I recommend that future studies explore how the presence of individual bee species in rural and urban habitats could be influencing pollen limitation and selfing in I. capensis.

In mixed stands of the annual Impatiens capensis and I. pallida, bumblebees visit I. pallida almost exclusively even when the nutritional reward of I. pallida is removed. This phenomenon contradicts certain models proposed for foraging behavior in simultaneously flowering species and those dealing with optimal foraging. Such foraging behavior could have potentially devastating effects on the nonpreferred species, especially if the plant is an annual. Both Impatiens species share the same primary pollinators when they grow allopatrically, but when they grow sympatrically I. pallida continues to attract bumblebees while I. capensis depends on hummingbirds and small bees for pollination. Thus competition for pollinators between these Impatiens represents an important plant-plant and plant·pollinator interaction with potential consequences. When I. capensis is less frequented by bumblebees when sympatric with I. pallida, I. capensis exhibits reduced fecundity. Mechanisms of interference through improper pollen transfer are described for the Impatiens species. Pollen of I. pallida adheres to and germinates on the stigmas of I. capensis and the pollen tubes reach the ovules. In contrast, pollen of I. capensis adheres poorly to I. pallida stigmas and fails to germinate. No hybridization occurs between the species. Scanning electron micrographs of pollen and stigma surfaces of the two species revealed no morphological differences. Among the floral characteristics examined, only flower color appeared to influence bumblebee preference for I. pallida. Differences between the species in ultraviolet absorbance patterns, perianth size and shape, odor, and nectar quantity and quality did not affect the pollinator preference of bumblebees. Differences in nectar characteristics and production rate were found among Impatiens populations. However, nectar quantity, quality, and production rates did not differ within allopatric or sympatric populations, but both species had higher nectar volumes with lower solute concentrations in the morning, and lower nectar volumes with higher solute concentrations in the late afternoon. Differences in nectar volumes among populations appeared to be associated with environmental factors affecting population sites. I. capensis avoids competition and maintains itself in sympatric populations with I. pallida by depending on hummingbirds and insects other than bumblebees as pollinators, and has the ability to produce cleistogamous flowers and their subsequent progeny to ensure sexual reproduction. However, inbred progeny of I. capensis are competitively inferior to outcrossed stock. Nevertheless, I. capensis does persist in mixed stands of I. pallida despite the absence of bumblebee pollination and the presence of lower seed set. / Ph. D. / incomplete_metadata

Invasive alien species are recognized as a major problem worldwide. They affect native flora and fauna negatively, resulting in loss of biodiversity and increased economic costs of the species’ themselves and management efforts. One of the most widely distributed invasive plant species – the Himalayan balsam (Impatiens glandulifera) – is inflicting damage to native plants in Sweden by overshadowing due to its tall stature and capacity to increase population numbers quickly over long distances. The purpose of this study was to examine the distribution of Himalayan balsam in urban versus rural areas in south, central, and northern Sweden. Five land cover classes were also compared to investigate potential differences in where Himalayan balsam is frequently observed. Species observations from Species Observation System (Artportalen by SLU Swedish Species Information Centre) were combined with land cover data from the Swedish Environmental Protection Agency to assess the distribution of Himalayan balsam over different cover classes. The results showed no significant differences for urban versus rural areas nor latitude, but some of the land cover classes were significantly different from one another. Himalayan balsam observations in forests on wetlands are significantly more reported compared to all other classes, and exploited lands and open lands had more reported observations than forests outside wetlands. Observations by the public are often characterised by opportunistic reporting behaviour, ultimately leading to bias in which species are reported. In conclusion, this study tested means to assess the distribution of Himalayan balsam among land cover classes and its results are consistent with other studies showing Himalayan balsam favours in moist habitats over other land cover classes. / Invasiva främmande arter ses som ett stort hot runt om i världen. Inhemsk flora och fauna blir kontinuerligt negativt påverkad av invasiva arter vilket resulterar i förlust av biodiversitet och ökade ekonomiska kostnader. En av de mest utspridda invasiva växtarterna – jättebalsamin (Impatiens glandulifera) – skadar inhemska växtarter i Sverige genom att överskugga dem samt skapa stora bestånd genom sin kapacitet att spridas långa distanser. Denna studies syfte var att undersöka jättebalsaminens utbredning i stads- och lantliga miljöer, samt geografiska områden i södra, centrala och nordliga delar av Sverige. Fem marktäckeskategorier undersöktes också för att se potentiella skillnader på habitat där jättebalsamin har rapporterats befinnas sig. Data från Artportalen (SLU Artdatabanken) användes i kombination med marktäckesdata från Naturvårdsverket. Studiens resultat fann inga signifikanta skillnader mellan stadsmiljöer och lantliga miljöer. Inga signifikanta skillnader kunde hittas för geografiska områden i södra, centrala och nordliga Sverige. Studien fann däremot signifikanta skillnader i rapporterade observationer bland marktäckesklasserna där skogar på våtmarker hade fler observationer per km2 jämfört med skogar utanför våtmarker, exploaterade marker och öppna marker. Observationer från allmänheten är ofta präglad av opportunistiska beteenden gällande rapporteringar, vilket kan leda till partiska data där vissa arter rapporteras medan andra ignoreras. Sammanfattningsvis testade denna studie utbredningen av jättebalsamin på marktäckesklasser och var förenlig med tidigare studier som visar att jättebalsamin är vanligare förekommande i fuktiga habitat jämfört med andra marktäckesklasser.

Investigations were carried out into the allelopathic potential of the invasive alien annual Himalayan Balsam (Impatiens glandulifera Royle) using a series of bioassays, including ones developed or adapted for this study. They were evaluated for their suitability to detect three of the four main modes of allelochemical release, namely leaching, exudation and decomposition. Assays which involved the measurement of lettuce radicles and hypocotyls gave reliable results and allowed a range of different Impatiens material, both living and dead, to be assessed and ranked according to the allelopathic effects demonstrated. Attempts were made to isolate resource competition from allelopathy using separately grown but connected donor and receiver plants and a density dependent design where single I. glandulifera plants were grown in pots with variable numbers of receiver plants. Results proved inconclusive. Initial experiments showed that the allelopathic potential of I. glandulifera varied according to the organ from which the material was derived. Pods, leaves and stems produced the greatest inhibition of lettuce seedlings. Effects on germination were not significant at most of the concentrations tested. Live roots of I. glandulifera plants produced pronounced orange staining of the agar into which they were placed and showed clear evidence of distance dependent inhibition of lettuce radicles. Effects were limited to growth rather than germination of the test plants. Germinating I. glandulifera seeds caused a significant inhibition of lettuce radicle elongation when the two species were grown together in an agar medium. The inhibitory effects increased significantly with increasing exposure time. Increasing I. glandulifera seedling number also produced significant reductions in lettuce radicle length. Dormant seeds, by contrast, stimulated growth. Dead seeds did not produce significant changes to the growth of the test plants. When rhizosphere soil was gathered from pot grown I. glandulifera plants, the results were mixed. Initial samples inhibited growth, whereas those collected from dying plants over a period of weeks stimulated growth. Further experimentation is required before the indications of allelopathic interactions demonstrated here can be applied to the behaviour of wild populations of I. glandulifera.

This research is an analysis of the explosive seed dispersal of Impatiens pallida fruit. Data was taken using high-speed video and analyzed using LoggerPro video analysis software. From the videos we discerned a qualitative model for dehiscence, a description of how the process unfolds, and from our data we deduced quantitative values for the velocity, momentum, and energy of the system. We were also able to glean a lower bound of Young’s modulus E of the fruit tissue. These results and the tools of analysis that generate them are the foundation for the development of a theoretical model of the plants motion. Our results also provide insights into Impatiens pallida’s evolutionary history by explaining its seed dispersal mechanism. A secondary benefit of this research is providing ecologist’s with new tools to analyze ultra-rapid movements in plants and fungi. These tools of analysis will assist in defining a plant’s or fungi’s evolutionary context and the ecological significance rapid motion plays.

No description available.

Impatiens glandulifera is an invasive species throughout Europe. It was introduced to the wild in 1918 by escape from private gardens as well as the transport of garden soil and waste. Impatiens glandulifera prefers moist soils with moderate shade and commonly grows in riparian environments. In the Umeå municipality in northern Sweden, where this study is focused, the number of Himalayan balsam observations has dramatically increased over the last few years. This study aimed to determine habitat and anthropogenic land-use factors that may have contributed to the spread of Himalayan balsam in the Umeå municipality. This was done by using data on recorded observations of the species in a database called Artportalen. In order to determine how abundant and in which habitats Himalayan balsam occurs in the Umeå municipality, data on recorded observations in Artportalen from the Umeå municipality region for the period 01-01-2021 to 31-12-2021 was used along with maps from Google Earth Pro and Google maps. It was found that Himalayan balsam is now common in the region and does not show a definitive preference for riparian habitats or for forest or open areas in the Umeå municipality. Human activities seemed to be the main contributor to the spread of Himalayan balsam in the Umeå municipality.

Impatiens walleriana, commonly grown as a herbaceous annual, is susceptible to Impatiens Necrotic Spot Virus (INSV). A lack of resistant cultivars leaves growers with the sole option of destroying infected plants before INSV spreads throughout their entire crop. Therefore, the introduction of INSV resistant cultivars would have the potential to save Impatiens growers a substantial amount of money. Virus resistance has been successfully conveyed in several crops by insertion of pathogen DNA into the host plant. One method of generating transgenic plants involves the use of Agrobacterium-mediated gene transfer. A commonly used technique involves transformation of explant tissue and subsequent regeneration in vitro under aseptic conditions. However, prior to our research there was no regeneration protocol suitable for Agrobacterium-mediated transformation of Impatiens walleriana available. Herein we report the development of a new method for regeneration of Impatiens walleriana using cotyledonary node culture. Using this technique, four regeneration media amended with 1, 3, 5, or 7µM of thidiazuron were evaluated for their ability to induce de novo shoot production in cotyledonary node explants, and evaluated for number of shoots produced per explant. Results showed a significantly greater frequency of regeneration and number of shoots per explant using media amended with 1µM of thidiazuron. This technique has shown to be repeatable and is not susceptible to ploidy instability. Unfortunately, damage to the cotyledonary node explants during Agrobacterium inoculation and transfection prevented regeneration of transformed shoots in several attempts. However, transient GFP expression after transfection of shoot pads derived from cotyledonary nodes with Agrobacterium strain LBA 4404 containing plasmid pHB2829 with nptII and S-GFP was obtained, indicating the possibility for this regeneration protocol to derive stably transformed Impatiens with INSV resistance. / Master of Science

The aim of the study was to study the invasion ecology and the to study the invasion of two species of the genus Impatiens, namely I. glandulifera and I. parviflora. I then chose the right bank of the Želivka river in the Czech-Bohemian highlands to study and survey the plant association and population of two mentioned species. Consequently I focused my study on the river biotope and the role of invasive species in it. Further I have worked up a research summary on the ecology of the invasion and the role of the above mentioned species in the riparian biotopes.

Three of Impatiens species are widespread in the Czech republic, one is native, two of them invasive. Because all species occur in relatively similar habitats, the question is, whether the invasive species can negatively affect the native species, or even the original can can be displaced. The aim of the thesis was: (i) to compare habitat requirments of the Impatiens species, (ii) to determine if the coexistence of species is possible, (iii) to assess the impact of invasive species to the original species. The investigation was carried out using two sets of permanent plots in 5 localities. In the first set with a total of 84 plots (combinations of occurrence of the three species) site characteristics as tree cover, soil humidity, slope and bare land cover were directly measured and nutrient, light, humidity and soil reaction characteristic assessed using Ellenberg indicator values. The second set contained a total of 45 plots with one of the native-invasive congener pair being removed and the intact controls. Number, cover and height of the plants were assesed. The key enviromental factors determining distribution of the species were soil moisture for I. noli-tangere and I. parviflora, and tree cover for I. glandulifera and I. parviflora. Ellenberg indicator values had poor explanation value;...