Invasiva växtarter är ett globalt problem som hotar inhemska ekosystem. Blomsterlupinen (Lupinus polyphyllis) är en invasiv flerårig växt som erhåller flera egenskaper som bidrar till dess framgångsrika etablering och spridning. Vägkanter agerar som landskapskorridorer för exotiska arter samtidigt som det är en viktig habitatrefug för många ängsväxter. För att effektivisera bevarandeåtgärder behövs en gedigen kunskap om målarten och dess egenskaper. Syftet med den här studien var att utvärdera två potentiella hanteringsmetoder av blomsterlupin i vägkanter. Slåtter är en redan etablerad strategi, men för att ta reda på om olika skördintensiteter påverkar återväxten av biomassa på olika sätt jämfördes en kontrollgrupp (ej skörd) och tre skördgrupper (1–3 skördar) med avseende på bladbiomassa, stambiomassa, blomställningsbiomassa och plantans totala biomassa. En annan potentiell hanteringsmetod utvärderades med fokus på fröbanken. Frön från blomsterlupin värmebehandlades i 40°C, 50°C och 70°C, och jämfördes mot frön utsatta för kontrolltemperatur (20°C). Varaktigheten för värmebehandlingar var 1, 5 och 15 minuter. Några frön utsattes för vattenbehandling innan värmebehandlingen för att bryta den fysiska vilan. Blomsterlupinfrön jämfördes mot tre andra arter i familjen ärtväxter (Fabaceae); blodklöver (Trifolium incarnatum), blålusern (Medicago sativa) och (Louts corniculatus). Det fanns en signifikant effekt beroende av skördintensitet på återväxt av stambiomassa, blomställningsbiomassa och plantans totala biomassa. Gällande bladbiomassa fanns ingen skillnad mellan grupperna. Faktumet att blomsterlupinen primärt investerar mer resurser på produktion av bladbiomassa kan anses positivt ur ett åtgärdsperspektiv. Återväxten av biomassa var emellertid beroende av plantans ursprungliga storlek, således skulle effekten av slåtter kunna skilja sig mellan individer i en population. Vattenbehandlingen bröt inte den fysiska vilan hos blomsterlupinfrön. Men en ökad temperatur under värmebehandlingen verkade ha en hämmande effekt för antalet grodda frön och MGT. Trots det återfanns ett relativt stort antal levande blomsterlupinfrön efter den sista observationsdagen. Det kan indikera att många frön skulle överleva en värmebehandling av fröbanken om behandlingen skulle implementeras som åtgärdsmetod. Metoden skulle förmodligen vara tidskrävande och dyr i förhållande till den önskade reducerande effekten på levande blomsterlupinfrön. För att utveckla resurseffektiva åtgärder för artens fröbank krävs mer kunskap. Slåtter verkar vara en bättre åtgärdsmetod om det genomförs vid rätt tidpunkt två gånger om året. / Invasive plant species are a global problem that threaten native ecosystems. The garden lupin (Lupinus polyphyllus) is an invasive perennial herb and possesses several traits, which enables successful establishment and dispersal. Road verges serve as landscape corridors for exotic species, as well as being an important refuge habitat for many grassland species. To make conservation managements more efficient, an extensive knowledge of the target species and it’s traits is required. The aim of this study was to evaluate two potential management strategies for garden lupin in road verges. Mowing is an established strategy already, but to find out if different cutting intensities will affect biomass regrowth differently, one control group (no cut) and three harvest groups (1-3 cuts) were compared regarding leaf biomass, stem biomass, inflorescence biomass and total plant biomass. Another potential management strategy was evaluated focusing on the seed bank. Seeds of garden lupin were heat treated at 40 °C, 50 °C, and 70 °C and compared to control seeds (20 °C). Duration of treatments was 1, 5, and 15 minutes. Some seeds were watered before the heat treatment to break physical dormancy. Seeds of garden lupin were compared to three other species in the Fabaceae family: Trifolium incarnatum, Medicago sativa, and Lotus corniculatus. I found a significant effect of cutting frequency on regrowth of stem biomass, inflorescence biomass, and total plant biomass. Regarding leaf biomass, there was no difference between harvest groups. The fact that garden lupin plants primarily invest more resources in leaf biomass regrowth can be regarded as positive from a management point of view. However, biomass regrowth was depended on initial plant size, and the mowing response might differ between individual plants in populations. The water treatment did not break the physical dormancy of garden lupin seeds. Increased temperatures during heat treatments seemed to have an inhibiting effect on both seed germination and mean germination time. However, a high number of vital garden lupin seeds were remaining after the last observation. This might indicate that many seeds would remain vital if seed bank heat treatments were implemented as a management strategy. The strategy would probably be time consuming and expensive in relation to the desired reducing effect on vital garden lupin seeds. To develop resource efficient management actions on the species’ seed bank, more knowledge is needed. Mowing seems like a better management option if it is implemented at the right time twice a year.

The objectives of this study were to determine the effects of two forms of polyacrylamide (PAM) conditioners (Cross-linked and Non-cross-linked PAM) on evaporation, saturated hydraulic conductivity, water retention, crust and crack formation of soils, seed germination, and seedling and tubeling growth. The two PAM conditioners, 0.2% concentration by weight, were mixed with seven soils of different textures (sandy loam, silt, silty clay loam, silt loam, fine sand, medium sand, and coarse sand) to investigate the effects on evaporation, saturated hydraulic conductivity, and water retention. Soil samples of different textures were brought to field capacity and placed in a growth chamber for two weeks to measure evaporation under a controlled environment. A second experiment was carried out in the field to determine the effects of the two PAM conditioners on seedling emergence of crested wheatgrass, Agropyron desertorum, as well as on soil cracking, penetrometer resistance, and soil moisture. The two PAMs were mixed with a silt loam Xerollic Calciorthid at 0.2% concentration by weight. Seedling emergence was monitored directly for two weeks. Soil moisture was measured by TDR. Cracking was described by photographic means. Penetrometer resistance was measured by a hand-held. penetrometer. The third experiment was also carried out in the field, using the same soil texture as in experiment 2, to investigate the effects of the two PAMs on soil moisture at depths between 25 to 45 cm and on sagebrush (Artemisia tridentata) growth. Evaporation was found to be significantly lower in the fine-textured controls than under the two PAM treatments. The sandy loam and sandy soils experienced significantly higher evaporation from the controls. The two PAM conditioners significantly reduced saturated hydraulic conductivity on all soil textures. Water retention increased in the PAM-treated textures at the matric potential range used (0.0, 0.05, 0.1, 1.5 MPa) • The PAM application also did not improve grass seedling emergence or improve soil moisture, and did not have any significant affects on sagebrush growth. Larger cracks were found in the two plots treated with PAM than the controls. Lower penetrometer resistance occurred in the two PAM treatments compared to the untreated control. From this study, it can be concluded that the application of PAM conditioners, at relatively high concentrations used, could be more viable on sandy textures. Other researchers are advised to try lower application rates than used here, particularly with finer textured soils.

Drought is the major environmental factor affecting crop growth, yield and quality. Two experiments were conducted to understand rice genotypic variability responses to drought stress conditions during seed germination and early-seedling growth. In Experiment I, the influence of wide range of osmotic stress on seed germination properties of 15 rice cultivars were studied using polyethylene glycol media. In Experiment II, seedling morph-physiological parameters including root traits were quantified by subjecting rice seedlings to three different soil moisture treatments, 100, 66 and 33% field capacity. Rice cultivars differed in their response to drought at both the stages. Cultivars were classified into different drought tolerant groups based cumulative drought response indices. Based on seed- and early-season growth and developmental responses, RU1104122, Rex, CL111 and RU1304154 were identified as drought tolerant among the rice cultivars tested. The identified tolerant cultivars will be a source for rice breeders to develop new drought tolerant cultivars.

Phacelia purshii Buckley and P. fimbriata Micheaux are two species that are nearly morphologically indistinguishable. Seed germination experiments showed that the high elevation endemic, P. fimbriata requires lower temperatures to trigger germination. Following interspecific crosses, pollen tubes enter ovules and maternal tissue of the gynoecium matures but hybrid diploid and triploid organs fail to develop. DNA sequences from the ribosomal DNA internal transcribed region showed that P. fimbriata and P. purshii comprise a monophyletic clade but that P. fimbriata is more differentiated from related species. In contrast, P. purshii supported significantly higher levels of intraspecific polymorphism. Phacelia fimbriata and P. purshii are sister species with similar morphology but they are unable to hybridize, they are differentiated in physiological characteristics related to environment, and they inhabit different elevations. This pattern of relationship and differentiation suggests P. fimbriata may be the product of ecological speciation.

Penstemon gibbensii and Penstemon haydenii are two rare, perennial forbs inhabiting remote areas of the western United States. P. gibbensii is listed as a sensitive species by the Bureau of Land Management (BLM) in Colorado, Utah, and Wyoming (Heidel, 2009). P. haydenii was designated as Endangered by the U.S. Fish and Wildlife Service in 1987 (Heidel, 2012). This thesis research was geared toward helping land managers in their efforts to protect and rehabilitate these species by providing understanding on different aspects of their seed ecology. My first study was a laboratory experiment performed on P. gibbensii and P. haydenii seed germination response to moist chilling and dry after-ripening. Wild harvested seeds were subjected to moist chilling at 2-4 °C for 0, 4, 8, 12, and 16 weeks and held in dry storage for approximately 2 years to determine effective methods for breaking primary dormancy. P. gibbensii seed germination increased consistently with increased length of chilling up to 16 weeks and exhibited habitat-correlated variation in this response. P. haydenii seed germination increased from 1 to 100% germination with 4 weeks of chilling. P. haydenii germination was greatest (96%) when incubated under a cool, diurnally-fluctuating temperature regime (10-20 °C) and responded positively to dry storage, increasing germination from 0 to 15%. My second study was an in situ field study designed to characterize the active seed bank of P. haydenii. We set up a transect line across a P. haydenii population and measured the number of seeds entering the seed bank, lost to predation post-dispersal, and persisting in the seed bank. P. haydenii does not appear to form an ecologically significant seed bank. Approximately 140 seeds/ 10m2 could potentially enter the seed bank but only 1 seed in the upper 10cm of sand persisted. Heavy post-dispersal insect predation resulted in a decrease in viability of nearly 30% in exposed P. haydenii seeds after just 12 hours. My third study explored the effects of burial by sand on P. haydenii. Wild-harvested seeds were planted in pots at 1, 2, 4, 6, 8, and 10cm deep in sand and incubated at 10-20 °C. Seed germination and mortality and seedling emergence were measured. The response of dormant seeds to post-burial incubation was determined. Burial depth decreased seedling emergence and seed germination. Shallow burial appears to induce secondary dormancy for seeds that don't germinate quickly, whereas deep burial appears to impose enforced dormancy in burial.

Blomsterlupin (Lupinus polyphyllus) är en iögonfallande invasiv växtart som i nuläget är spridd över större delen av Sverige utom nordvästra delen av Norrbotten. Framtagande av effektiva bekämpningsmetoder är av stor betydelse eftersom spridning av blomsterlupin hotar känsliga naturhabitat, exempelvis så kallade artrika vägkanter. Detta arbete fokuserar på värmebehandling, en metod som potentiellt kan användas för desinfektion av lösa jordmassor, som anses vara en av de största spridningsvektorerna för blomsterlupin. Arbetets syfte är att med hjälp av uppsamlade data undersöka om det finns en optimal temperatur och exponeringstid för effektiv minskning av antalet grodda blomsterlupinfrö. Utöver detta, utvärderas effekterna av förbehandling i form av rispning och blötläggning av frön. Inom experimentet behandlades blomsterlupinfrö med olika temperatur under olika exponeringstid. Hälften av fröna fick förbehandling i form av blötläggning efter rispning av skalet inför uppvärmningen. Frön värmebehandlades i 88˚C, 93˚C, 98˚C och 103˚C under 1, 3, 5 och 10 minuters tid. Efter värmebehandlingen fick fröna gro i ett odlingskåp. Resultatet visar att förbehandling, ökad temperatur och ökad exponeringstid bidrar till signifikant minskning av andel grodda blomsterlupinfrö. Ju högre temperaturen var, desto större var effekten av längre exponeringstid. Effekten av hög temperatur och lång exponeringstid var starkare om fröna var förbehandlade. Resultatet tyder på att värmebehandling potentiellt är en effektiv metod för bekämpning av blomsterlupinfrö. Vidare experiment krävs för att undersöka hur denna metod kan effektiviseras och tillämpas i praktiken, i synnerhet vid uppvärmning av stora volymer av jordmassor. / Garden lupine (Lupinus polyphyllus) is an eye-catching invasive herb that is currently spread over the major part of Sweden except for the northwestern part of Norrbotten county. The development of effective control methods is of great importance because the spread of Garden lupine threatens sensitive natural habitats, for example species rich road verges. This work focuses on heat treatment, a method that can potentially be used for the disinfection of soil masses, which is considered one of the major dispersal vectors for Garden lupine. The purpose of this work is to use the collected data to investigate whether there is an optimal temperature and duration of exposure for effective reduction of the number of germinated Garden lupine seeds. In addition, this work evaluates the effects of pre-treatment in the form of scarifying and soaking of seeds. Within the experiment, Garden lupine seeds were treated with different temperatures and different duration of exposure. Half of the seeds received pre-treatment in the form of soaking after scarifying the seed coat before heating. After that, seeds were heat treated at 88˚C, 93˚C, 98˚C and 103˚C for 1, 3, 5 and 10 minutes. After the heat treatment, the seeds were allowed to germinate in a growth chamber. The result shows that pre-treatment, increased temperature and increased exposure time contribute to a significant reduction in the percentage of germinated Garden lupine seeds. The higher the temperature, the stronger was the effect of a longer exposure time. The effect of high temperature and long exposure time was stronger if the seeds were pre-treated. The result suggests that the heat treatment is potentially an effective control method for Garden lupine seed. Further experiments are required to investigate if this method could be made more efficient and applied in practice, particularly when heating large volumes of soil masses.

No description available.

Soil salinity and the arid climate in Libya are major constraints in agriculture and predominantly in foodstuff production which are limiting wheat production and yield. The effect of pre-sowing seed treatments with 50 mM of KCl, NaCl, CaCl2, and distilled water as hydropriming on germination and early seedling growth in two wheat (Triticum aestivum L.) cultivars S-24 (tolerant) and Slambo (untested before) under 0, 100, 200 and 300 mM NaCl concentrations was examined. CaCl2 was the only priming treatment that significantly improved the germination percentage, germination rate, and mean germination time in both cultivars under almost all NaCl concentrations. Thus, priming with CaCl2 was selected for further experiments. In the greenhouse, seeds primed with 50 mM of CaCl2 also improved the emergence percentage, emergence rate, shoot and root length, and fresh and dry weight of shoots and roots of both cultivars under all NaCl concentration except at 300 mM where the emergence was completely inhibited. The response of wheat cultivars to three compost treatments including cow manure compost (CC), greenwaste compost (GC) and 50:50 mixture (mix) between them and sand at percentage inclusions of 10 and 30 % by weight under 0, 100, 200, and 300 mM of NaCl was also investigated. Among all compost treatments, 30% GC and 30% mix were the best treatment and improved almost all growth parameters under salt stress, and 30% GC was also the only treatment that had any emergence at 300 mM NaCl. 30% GC and 30% mix were selected for further experiments. The effect of the combination of the selected priming agent (CaCl2) and the best two compost treatments (30% GC and 30% mix) on the emergence and early seedling growth of both cultivars was tested. The results showed that all the treatments enhanced plant growth parameters including seedling ion uptake in both cultivars, with preference to primed seeds sown in 30% GC. The treatments had the following order of the performance of both cultivars under salt stress. Primed seeds sown in 30% GC > unprimed seeds sown in 30% GC > primed seeds sown in 30% mix > unprimed seeds sown in 30% mix. This enhancement is possibly due to the provision of Ca2+ and / or the improvement in the availability of water as both of them were improved by the application of priming and compost.

Elevated atmospheric CO2 has been implicated as a driver of increased liana abundance worldwide. Known as disturbance creators and beneficiaries, lianas possess the potential to significantly influence forest ecosystems. I investigated the early-invasion dynamics of Euonymus fortunei (wintercreeper), an evergreen liana that is invading forests in eastern North America, disrupting native plant communities and ecosystem functions. Wintercreeper is widely cultivated as an ornamental groundcover, frequently invading natural areas via asexual stem growth. Invasion of remote natural areas is dependent upon seed transport and may occur less frequently. I examined the mechanisms of seed dormancy by conducting a ‘move-along’ experiment using fresh and after-ripened seeds. Additionally, I sought to characterize the nature of seed dispersal by birds by deploying seed traps within an invaded forest in central Kentucky. Wintercreeper seeds displayed conditional nondeep physiological dormancy. Although germination occurs at high velocity following cold stratification, a cold period was only facultative to break dormancy. While fresh seeds had greater germination rates (98.6%) compared to after-ripened seeds (85.7%), after-ripened seeds experienced earlier germination (41 days across all treatments). My findings also indicate that bird-mediated seed dispersal occurs throughout the winter from seeds that after-ripen on maternal liana phanerophytes. Overall, these data suggest wintercreeper seeds are capable of dispersing and recruiting in areas with mild to non-existent winters. The invasion of natural areas by exotic invaders is regulated by biotic and abiotic processes, which influence the invader’s success or failure. I studied the vegetation and soil effects of paired invaded (INV), uninvaded (NAT), and ‘restored’ (RES) sites on the germination and survival of wintercreeper seeds and seedlings. The effect of aril (with vs. without) was also tested, both in the field and in vitro. In the field, total germination and first year survival were 55.6% and 24.2%, respectively, across treatments. Total germination was unaffected by treatments, yet vegetation (P = 0.0016) and aril (P = 0.001) treatments significantly influenced germination rates over time, including delayed germination of seeds with arils. The proportion of germinated seedlings that survived was significantly different based on vegetation (P = 0.054) and aril (P = 0.071) treatments after the first winter of growth, but not prior to the first winter. The proportion of seedling survival was significantly lower among seeds dispersed with an aril and seeds sown within INV treatments; there were no interactive effects. Finally, I examined how seedling density and growth habit (horizontal vs. vertical) influenced plant survival, growth, and allometry. I also tested extractable soil C, N, P, K, Ca, and Mg prior to planting and after 17 months of soil conditioning. I found evidence that increased planting density negatively influenced growth among individual plants (lower survival, basal diameter, shoot mass, root mass). At the plot level, high-density plantings yielded greater stem length, and shoot, root, and combined biomass, indicating positive frequency dependence for this species. Soil analyses indicated C, N, P, Ca, and Mg significantly increased (P < 0.05) over the course of the experiment. I conclude that in wintercreeper, prominent asexual propagation leads to aggregate populations whose total contributions to above- and belowground biomass are positively correlated with density, even though individual plant fitness is not. Altogether, this work provides insight into how wintercreeper invasions occur at broad and fine scales. This information will provide a foundation for future wintercreeper studies and aid land managers in their prevention and control strategies.

As jabuticabeiras são árvores tipicamente brasileiras, de origem subtropical e tem como principal distribuição o centro sul do país. Dentre elas está a Sabará, a qual é a mais cultivada em todo o país. Sua propagação é realizada basicamente através de sementes, pois métodos de propagação vegetativa ainda são pouco utilizados. Contudo, a enxertia tem se mostrado promissora e a necessidade de porta enxertos bem formados torna-se essencial para o sucesso desta técnica. As sementes de jabuticaba são classificadas com recalcitrantes por serem sensíveis à dessecação o que dificulta seu armazenamento. As jabuticabeiras Sabará (Myrciaria jaboticaba Berg) são frutas nativas do Brasil, cuja distribuição concentra-se no centro sul do país. Trata-se de uma espécie subtropical com frutos pequenos, de coloração escura e muito doces, sendo utilizados principalmente para a confecção de geleias, licores e vinhos, pois o fruto in natura possui vida de prateleira muito curta, de até dois dias. Fatores externos e de cultivo limitam a produção de frutos e um deles poderia ser a presença de luz solar na maturação do fruto. O objetivo deste trabalho foi avaliar a influencia da luz solar na maturação do fruto de jabuticaba, através da divisão da planta em quadrantes e se a germinação da semente diminui durante o armazenamento em dois ambientes, geladeira e temperatura ambiente. Para a primeira etapa dividiu-se cinco plantas em quadrantes Norte, Sul, Leste e Oeste, onde foram coletados frutos para a análise físico-química e os parâmetros avaliados foram: o diâmetro, peso do fruto, Brix, acidez titulável, o índice de maturação e pH. Foi observado que apenas para o parâmetro Brix e, consequentemente para o índice de maturação, houve diferença estatística entre o quadrante Sul dos demais. A partir disso pode-se concluir que há influência da luz solar sobre alguns parâmetros de qualidade do fruto de jabuticabeira. Para o armazenamento sementes de jabuticaba Sabará foram coletadas e armazenadas em geladeira (5°C) e temperatura ambiente (~25°C) durante 105 dias em saquinhos de polietileno. Foram postas para germinar aos 7, 14, 21, 28, 42, 56, 70 e 105 dias e foram feitas avaliações semanais. Foi possível perceber que não houve diferença estatística entre os dois ambientes, mostrando que se trata de uma semente tolerante a temperaturas baixas para o armazenamento. A partir do teste de secagem foi possível observar o comportamento recalcitrante da semente, pois esta perdeu o poder germinativo com a perda gradual de umidade. Conclui-se, então, que a semente de jabuticaba é recalcitrante, porém classificada como minimamente recalcitrante já que tolerou armazenamento em temperaturas baixas. / Jabuticaba trees are typical Brazilian trees and are mainly distributed in the country\'s center- south. Among them there is Sabará, which is the most spread specie through Brazil. Its propagation is basically made with seeds since the vegetative propagation is still less used. However, grafting seems to be efficient and the necessity of good rootstocks becomes essential to the technique\'s success. Jabuticaba seeds are classified as recalcitrant because they are drying sensible turning the storage difficult. Jabuticaba Sabará trees (Myrciaria jaboticaba Berg) are brazilian native fruits, which are mainly distributed in the country\'s center-south. It is subtropical specie with small fruits, dark colored and very sweet, being used to make jellies, liquors and wines, since in natura fruits are very perishable not lasting two days. This work aimed to evaluate the influence of the sun light in jabuticaba\'s maturation and if the germination decrease during the storage in two different environments. It was possible to notice that during jabuticaba\'s development it was possible to notice that TSS, and consequently the TSS/TTA ratio, was influenced by the position of the fruit on the tree. The south side had lower results compared to the other quadrants, showing that there should be a sunlight influence in some quality parameters in jabuticaba\'s fruits. For storage test jabuticaba\'s seeds were collected and stored in fridge (5°C) and in environmental temperature (~25°C) during 105 days in polyethylene bags. Germination tests were taken at 7, 14, 21, 28, 42, 56, 70 e 105 days and weekly evaluations were made. It was possible to notice that there were no differences between both environments, showing that this seed tolerates low storage temperatures. From the drying test it was possible to observe the recalcitrant behavior of the seed, since it lost its germination power with the humidity loss. Therefore, it is possible to conclude that jabuticaba\'s seeds are recalcitrant, however it could be classified as minimally recalcitrant due the fact that it could be stored in low temperatures.