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Most diurnal birds have cone-dominated retinae and tetrachromatic colour vision based on ultra-violet/violet-sensitive UV/V cones expressing short wavelength-sensitive opsin 1 (SWS1), S cones expressing short wavelength-sensitive opsin 2 (SWS2), M cones expressing medium wavelength-sensitive opsin (RH2) and L cones expressing long wavelength-sensitive opsin (LWS). Double cones (D) express LWS but do not contribute to colour vision. Each cone is equipped with an oil droplet, transparent in UV/V cones, but pigmented by carotenoids: galloxanthin in S, zeaxanthin in M, astaxanthin in L and a mixture in D cones. Owls (Strigiformes) are crepuscular or nocturnal birds with rod-dominated retinae and optical adaptations for high sensitivity. For eight species, the absence of functional SWS1 opsin has recently been documented, functional RH2 opsin was absent in three of these. Here we confirm the absence of SWS1 transcripts for the Long-eared owl (Asio otus) and demonstrate its absence for the Short-eared owl (Asio flammeus), Tawny owl (Strix aluco) and Boreal owl (Aegolius funereus). All four species had transcripts of RH2, albeit with low expression. All four species express all enzymes needed to produce galloxanthin, but lack CYP2J19 expression required to produce astaxanthin from dietary precursors. We also present ocular media transmittance of the Eurasian eagle owl (Bubo bubo) and Short-eared owl and predict spectral sensitivities of all photoreceptors of the Tawny owl. We conclude that owls, despite lacking UV/V cones, can detect UV light. This increases the sensitivity of their rod vision allowing them, for instance, to see UV-reflecting feathers as brighter signals at night.

Today, there is good knowledge of the physiological basis of bird colour vision and how mathematical models can be used to predict visual thresholds. However, we still know only little about how colour vision changes between different viewing conditions. This limits the understanding of how colour signalling is configured in habitats where the light of the illumination and the background may shift dramatically. I examined how colour discrimination in zebra finch (Taeniopygia guttata) is affected by adaptation to different backgrounds. I trained finches in a two-alternative choice task, to choose between red discs displayed on backgrounds with di fferent colours. I found that discrimination thresholds correlate with stimulus contrast to the background. Thresholds are low, and in agreement with model predictions, for a background with a red colour similar to the discs. For the most contrasting green background, thresholds are about five times higher than this. Subsequently, I trained the finches for the detection of single discs on a grey background. Detection thresholds are about 2.5 to 3 times higher than discrimination thresholds. This study demonstrates close similarities in human and bird colour vision, and the quantitative data offer a new possibility to account for shifting viewing conditions in colour vision models.

The leachate obtained from bokashi fermentation household vessels, are among proponents of the bokashi method believed to be useful as a biofertilizer. The bokashi fermentation method does not lead to foul odours as it is anaerobically fermented in air-­tight bins with lactic acid bacteria, among other groups of microorganisms, and is therefore interesting in the light of an increasing interest of urban farming and unexploited resources of plant mineral nutrients within the urban area. To examine the potential use of bokashi fermentation leachate as a biofertilizer in an urban farming context, leachate obtained from fermentation of food waste from four different sources in Malmö and Lund, Sweden, was tested on pak choi. The leachate was tested in a sand substrate, a garden waste compost substrate and a peat substrate, in order to give a general idea on how the leachate could be applied in actual situations in urban farming projects, with varying use and availability of substrates and soil. The plant mineral content of the leachates varied depending on food source, although the leachates were generally low in nitrogen, supposedly as a result of denitrification during the fermentation process. Thus, substrates low in nitrogen gave poor growth for all leachate treatments, although significant difference between different leachate treatments, were found in all substrates. All leachates were relatively high in potassium and phosphorous. The plants were fertilized with two concentrations of leachates diluted in water. Treatments with higher concentration of leachate gave different shoot weight depending on the food waste source of the leachate. The content of sodium and chloride in the leachates varied remarkably depending on food waste source, and it was concluded that avoidable food waste contained higher amounts than unavoidable food waste, making unavoidable food waste a more appropriate source for production of bokashi leachate fertilizer.

Domestication processes tend to release animals from natural selection and favour traits desired by humans, such as food-production and co-operative behaviour. A side effect of such selective breeding is the alteration of unintended traits. In this paper, we investigate how active selection for egg production in chickens has affected the visual system, in particular the optical sensitivity that relates to the ability of chickens to see in dim light. We measured eye dimensions as well as the pupil diameter at different light intensities (the steady state pupil dynamics), in adult male and female White Leghorns and the closest relatives to their ancestor, the Red Junglefowls. With this information, we calculated the focal length and optical sensitivity (f-number) of the eyes. Males have larger eyes than females in both breeds and White Leghorn eyes are larger than those of Red Junglefowls in both sexes. The steady state pupil dynamics is less variable, however, the combination of pupil dynamics and eye size gives a higher optical sensitivity in Red Junglefowl eyes than in White Leghorns at light intensities below approximately 10 cd/m2. While eye size and focal length match the larger body size in White Leghorns compared to Red Junglefowls, the steady state pupil dynamics do not. The reason for this is likely to be that eye morphology and the neuro-muscular control of the pupil have been affected differently by the strong selection for egg production and the simultaneous release of the selection pressure for high performing vision. This study is the first description of how optical sensitivity has changed in a domesticated species and our results demonstrate important considerations regarding domestication processes and sensory ability.

I detta försök har Calibrachoa ’Callie Bright Red’ odlats i 9 olika behandlingar av LED-belysning underifrån. Samtliga behandlingar utfördes i växthuskammare med ett tredelat dygn på 8 timmar naturligt dagsljus, 8 timmar endast LED-belysning och 8 timmar mörker. Behandlingarna skiljde sig åt med avseende på ljuskvalitet och färgerna vit, röd, blå, gul och grön, samt kombinationer av dessa, användes. Som jämförelse fanns även ett led där vitt ljus gavs ovanifrån på konventionellt sätt. Fotoreceptorerna fytokrom och blåljusreceptorer i växter påverkar morfologisk utveckling vad gäller ur kulturväxtsammanhang intressanta aspekter som sträckningstillväxt och blomning. I detta försök testades hur ljusbehandling kan påverka en representativ krukodlad prydnadsväxt (Calibrachoa), för att eventuellt kunna ersätta eller komplettera kemiska retarderingsmedel i strävan efter att producera kompakta prydnadsväxter med stor biomassa men förhållandevis kort internodielängd. LED-belysning avger förhållandevis lite infraröd strålning. Däremot uppstår en värmeavgång av den energi som ej omvandlas till ljusenergi. Armaturerna placerades direkt på odlingsbordet mellan växtraderna, så att värme från armaturerna på så vis skulle kunna strömma uppåt mot kulturen och komma växterna till godo. På samma gång undveks skuggeffekter av bladverkets övre skikt på blad längre ner, genom att belysningen skedde underifrån. Signifikant skillnad vad gäller internodielängd kunde påvisas i jämförelse mellan plantor som odlats i vitt ljus och plantor som odlats i rött ljus. Ingen signifikant skillnad kunde påvisas vad gäller färsk- och torrvikt i jämförelser mellan behandlingarna, vilket tyder på att röd behandling ledde till välvuxna men kompaktare plantor och vit behandling till mer långsträckta. I övrigt var längsta skottlängden lägst hos plantor i blå behandling under försöket och vid försökets avslutande, dock ej med någon signifikant skillnad. Plantor som fått belysning ovanifrån fick mer uppåtrikta, Different wavelengths of light lead to different morphological responses in plants, and the possibility to control spectral output in LED-lighting opens up new applications of artificial light in greenhouse production. One goal of this study was to examine the possibilities to grow compact plants without application of chemical growth retardants, as chemical growth retardants are considered negative from environmental and workers’ health prespective. In this study Calibrachoa ’Callie Bright Red’ were grown in different wavelengths from light emitting diodes placed below the plants. The idea of placing the light source below the plant was to reduce shade effects from light fixtures, and to benefit from heat delivered from the lamps through convection. As a control, plants were also grown with light from above. LED allows the application of monochromatic light, which is a prerequisite for complete control of spectral composition. The colors used were: white, red, blue, yellow and green. Also treatments with mixed wavelengths were performed. There were significant differences in internodal length between treatments red and white light from below. No other significant differences were detected, however, visual differences in the appearance of the plants were obvious.