Search results for "yhteyttäminen"
showing 8 items of 8 documents
Chlorophyll a fluorescence illuminates a path connecting plant molecular biology to Earth-system science
2021
Remote sensing methods enable detection of solar-induced chlorophyll a fluorescence. However, to unleash the full potential of this signal, intensive cross-disciplinary work is required to harmonize biophysical and ecophysiological studies. For decades, the dynamic nature of chlorophyll a fluorescence (ChlaF) has provided insight into the biophysics and ecophysiology of the light reactions of photosynthesis from the subcellular to leaf scales. Recent advances in remote sensing methods enable detection of ChlaF induced by sunlight across a range of larger scales, from using instruments mounted on towers above plant canopies to Earth-orbiting satellites. This signal is referred to as solar-in…
Ultrafast structural changes within a photosynthetic reaction centre
2021
Nature <London> / Physical science 589, 310 - 314 (2021). doi:10.1038/s41586-020-3000-7
Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae
2015
The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly…
Simultaneous non-invasive gas analysis in artificial photosynthesis reactions using rotational Raman spectroscopy
2022
Optimising reactions in artificial photosynthesis research requires screening of many reaction and operation parameters, which is often resource-intense and time-consuming. In this paper, we demonstrate the use of a rotational Raman-based spectrometer for non-invasive quantification of several gases (H2, O2, N2, CO, CO2) with short analysis times (15 s), enabling high throughput screening. Furthermore, with this device, reaction progress can be monitored in situ, by real-time simultaneous quantification of multiple gases. We have applied this instrument and developed a method to study the O2 dependency of a prototypic light-driven hydrogen evolution reaction, showcasing the value of this ap…
Structural basis for light control of cell development revealed by crystal structures of a myxobacterial phytochrome
2018
Phytochromes are red-light photoreceptors that were first characterized in plants, with homologs in photosynthetic and non-photosynthetic bacteria known as bacteriophytochromes (BphPs). Upon absorption of light, BphPs interconvert between two states denoted Pr and Pfr with distinct absorption spectra in the red and far-red. They have recently been engineered as enzymatic photoswitches for fluorescent-marker applications in non-invasive tissue imaging of mammals. This article presents cryo- and room-temperature crystal structures of the unusual phytochrome from the non-photosynthetic myxobacterium Stigmatella aurantiaca (SaBphP1) and reveals its role in the fruiting-body formation of this ph…
Peruskoulun 8-luokkalaisten ymmärrys yhteyttämisestä ja opetuksen vaikutus ymmärrykseen
2010
Peruskoulun kahdeksasluokkalaisten ymmärrystä yhteyttämisestä ja opetuksen vaikutusta ymmärrykseen tutkittiin konstruktivistiseen oppimiskäsitykseen pohjautuen. Tutkimuskysymyksiä olivat: miten kahdeksasluokkalaiset ymmärtävät yhteyttämisen biologisena ilmiönä ja kemiallisena prosessina, millainen vaikutus opetuksella on oppilaiden ymmärrykseen ja sen muuttumiseen yhteyttämisestä sekä onko saman opetusryhmän sisällä ja opetusryhmien välillä eroa yhteyttämisen ymmärtämisessä. Tutkimuskohteena oli kaikkiaan 45 kahdeksasluokkalaista Jyväskylän Normaalikoulusta ja Mikkelin Urheilupuiston koulusta. Tutkimus toteutettiin lukuvuonna 2009–2010, jolloin aineistoa kerättiin avoimella kysymyksellä enn…
"Tärkeintä kasvin kasvamiselle on, että se kastuu" : 2., 4. ja 6. -luokkalaisten käsityksiä kasvien kasvamisesta ja ravitsemuksesta
2002
Sexes in gynodioecious Geranium sylvaticum do not differ in their isotopic signature or photosynthetic capacity
2017
In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductance, transpiration rate, WUE and isotopic signatures were measured in plants growing in two habitats differing in light availability. Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference in seed output between …