Kimmo Syrjänen

Positive Effects of Pollination on Subsequent Size, Reproduction, and Survival of Primula Veris

We conducted three experiments in which we applied additional hand pol- lination, flower removal, and leaf removal treatments in various combinations to Primula veris, a perennial spring-flowering rosette species. The purpose of the study was to determine whether the seed set of Primula veris was limited by pollen availability or by other resources, and whether there were measurable costs of reproduction. Hand pollination in the beginning of experiments significantly increased current seed set in only one of the three experiments. It also increased the next-year fruiting probability in that first experiment. In the second experiment, hand pollination did not significantly affect current seed set, but we nevertheless observed enhanced leaf growth in the treatment year and the two following years, and increased flowering frequency, fruiting frequency, and survival in the two following years. In the third experiment, after hand pollination we observed a higher net photosynthetic capacity of the leaves and, again, increased leaf growth in the treatment year and a higher flowering probability in the following year. The positive effect of hand pollination was even clearer when the leaves of the plants were removed at the beginning of the experiment. However, the treatment in which all the flowers were removed had effects on subsequent performance similar to those of the hand-pollination treatment, suggesting trade-offs. Thus, we did not observe any costs associated with reproduction after supplemental hand pollination; on the contrary, hand pollination resulted in increased survival, size, and reproduction of the plants in the subsequent years.

Multiple origins of symbioses between ascomycetes and bryophytes suggested by a five-gene phylogeny

Numerous species of microscopic fungi inhabit mosses and hepatics. They are severely overlooked and their identity and nutritional strategies are mostly unknown. Most of these bryosymbiotic fungi belong to the Ascomycota. Their fruit‐bodies are extremely small, often reduced and simply structured, which is why they cannot be reliably identified and classified by their morphological and anatomical characters. A phylogenetic hypothesis of bryosymbiotic ascomycetes is presented. New sequences of 78 samples, including 61 bryosymbionts, were produced, the total amount of terminals being 206. Of these, 202 are Ascomycetes. Sequences from the following five gene loci were used: rDNA SSU, rDNA LSU, RPB2, mitochondrial rDNA SSU, and rDNA 5.8S. The program TNT was used for tree search and support value estimation. We show that bryosymbiotic fungi occur in numerous lineages, one of which represents a newly discovered lineage among the Ascomycota and exhibits a tripartite association with cyanobacteria and sphagna. A new genus Trizodia is proposed for this basal clade. Our results demonstrate that even highly specialized life strategies can be adopted multiple times during evolution, and that in many cases bryosymbionts appear to have evolved from saprobic ancestors.

The cost of reproduction in Primula veris: differences between two adjacent populations

The effect of flower and leaf removal on Primula veris was studied in two populations close to each other. Removal of both flowers and leaves resulted in decreased growth, flowering and reproduction in the next two years in both populations; there was no change in survival. In one population, removal of all flowers increased the flower number, the flower stalk length and the leaf area, and doubled the seed set in the year following the treatment. In the other population flower removal slightly decreased the seed set in the next year, while plant size did not differ from the control group. There were no significant differences in seed germinability between any of the experimental groups