0000000000273614
AUTHOR
Markku Käpylä
Pollen‐tube growth rate and seed‐siring success among Betula pendula clones
The aim of this study was to investigate whether genetically different pollen donors (Betula pendula clones) differed in pollen-tube growth rate across 11 maternal plants and in vitro, and whether the differences between the donors were consistent across the recipients. To compare the seed-siring success of competing pollen donors, a two-donor hand-pollination experiment with six donors and six recipients was conducted. The experiments were performed at a plastic-house seed orchard. The donors showed significant variation in pollen-tube growth rate on all the 11 recipients. The rankings of the pollen donors were statistically consistent across different maternal plants. A significant positi…
Diurnal Variation of Non-Arboreal Pollen in the Air in Finland
Abstract This study was carried out in Jyvaskyla and Turku, in central and southern Finland, with Burkard spore traps. The average diurnal variation of all non-arboreal pollen types found in sufficient quantities is presented. A high concentration of Artemisia pollen lasting 4–8 hours was found mainly in the morning. The highest concentrations of Brassicaceae, Calluna, Cyperaceae and Rosaceae occurred during the daylight hours, often with no definite peaks. The peak occurrence of Chenopodiaceae, Compositae and Plantago pollen was around 12.00 and of Rumex from 06.00 to 10.00. The diurnal variation of Poaceae pollen varies considerably depending on the species flowering at the time. Peaks oc…
Diurnal variation of tree pollen in the air in finland
Abstract The pollen was collected with Burkard spore traps in Turku and Jyvaskyla, in southern and central Finland. Selected days of high concentration were analysed for hour to hour concentrations. The diurnal variation of pollen concentration was variable in Alnus, Betula, Juniperus and Pinus, while Picea, Populus, Quercus, Salix and Ulmus had regular daytime maxima och nightly minima. The pollen concentrations were closely correlated with increasing temperatures and decreasing relative humidities. A significant relationship with wind speed was also found, except in Alnuts and Betula. The most significant relationships with wind speed were found in Salix and Quercus, the pollen of which t…
Do pollen donors with fastest-growing pollen tubes sire the best offspring in an anemophilous tree,Betula pendula(Betulaceae)?
The relationship between pollen and progeny performance has been a subject of many studies but the evidence for pollen-tube growth rate as an indicator of progeny fitness is equivocal. We used an anemophilous tree, Betula pendula, to examine the relationship between pollen-tube growth rate and seed and seedling performance. We crossed nine maternal plants with pollen from six pollen donors in a clonal B. pendula seed orchard, measured the pollen-tube growth rates for every cross, and analyzed the performance of the resulting seeds and seedlings. The only significant positive correlation was found between pollen-tube growth rate and seed mass when we controlled for seed number per infloresce…
Effects of temperature and pollination site on pollen performance in Betula pendula Roth – evidence for genotype-environment interactions
We studied whether the differences between genetically different pollen donors (Betula pendula Roth clones) with respect to pollen-tube growth rate were consistent under different thermal conditions during pollen germination in vivo and in vitro. We conducted a single-donor hand-pollination experiment with same pollen donors and recipients in a plastic house seed orchard and at an outdoor clone collection. The prevailing daily mean temperature during pollen germination was 13°C higher in the plastic house than outdoors. The pollen-tube growth rate of each pollen donor was additionally determined in vitro on agar medium at five temperatures (10°, 15°, 22°, 30° and 35°C). A significant intera…
An evaluation of the microscopical counting methods of the tape in hirst-burkard pollen and spore trap
Abstract Three different sampling units in current use and different sampling strategies were tested. Randomly placed microscope fields are good in estimating the daily mean concentration, but very big sample size is needed. Traverses across the slide in systematic order are best to estimate the shortterm concentrations and diurnal variation. A formula for the estimation of the error in one transverse traverse is given. Twelve transverse traverses in systematic order is also enough to estimate the daily mean concentration. One or two traverses along the length of the slide give often unreliable estimates because of the irregularities in the transverse variation of the particle concentration…
Influence of Content Knowledge on Pedagogical Content Knowledge: The case of teaching photosynthesis and plant growth
International audience; Abstract The aim of the research was to investigate the effect of the amount and quality of content knowledge on pedagogical content knowledge (PCK). The biological content photosynthesis and plant growth was used as an example. The research sample consisted of 10 primary and 10 secondary (biology) teacher students. Questionnaires, lesson preparation task and an interview were used to collect data. Primary student teachers' were not aware of students' conceptual difficulties and had problems in choosing the most important content. Neither of the groups had knowledge on suitable experiments and demonstrations, which indicates that PCK should be explicitly taught. The …
Adhesives and mounting media in aerobiological sampling
Abstract Because microscopical identification and counting is vital in most aerobiological studies, pollen and spores are usually collected on some adhesive. The adhesives should not be water-soluble. For optically best results water-soluble mounting media with refractive indices about 1.40–1.45 are used. There are compatibility problems between water insoluble adhesives and watery mounting media. The former tend to move to stripes or droplets, distorting the image and moving the spores from their original positions. To solve this problem several adhesives based on silicone oils, silicone greases and vaseline or their mixtures were tested. The usual watery mounting media, glycerine gelatine…
A phenomenological view of pictures in teaching and a novel method for analysing them
In this paper a novel method for analysing the content and teaching potential of pictures is presented. It is the four-field method, which is based on phenomenological thoughts about human experience, which combines factual knowledge with emotions and personal and social meanings. A biological example is given. Around this idea a course unit for using pictures in science teaching was organized. It was used in the training of both primary and secondary level teachers. From picture analysis the course unit proceeds to planning the use of pictures in teaching. A classification of the teaching functions of pictures is presented.