Pertti Pulkkinen

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Oaks have been one of the classic model systems in elucidating the role of polyphenols in plant–herbivore interactions. This study provides a comprehensive description of seasonal variation in the phenolic content of the English oak (Quercus robur). Seven different trees were followed over the full course of the growing season, and their foliage repeatedly(More)
Recent work has shown a potential role for both host plant genotype and spatial context in structuring insect communities. In this study, we use three separate data sets on herbivorous insects on oak (Quercus robur) to estimate the relative effects of host plant genotype (G), location (E), and the G x E interaction on herbivore community structure: a common(More)
From the perspective of a specialist herbivore, how homogenous are individual tree crowns as patches of habitat? We partitioned variation in physical and chemical host leaf traits and in the abundance and performance of a specialist oak leaf miner, Tischeria ekebladella , into variation at different hierarchical levels. For the phenolic contents of the(More)
Restoration of polluted sites via in situ bioremediation relies heavily on the indigenous microbes and their activities. Spatial heterogeneity of microbial populations, contaminants and soil chemical parameters on such sites is a major hurdle in optimizing and implementing an appropriate bioremediation regime. We performed a grid-based sampling of an aged(More)
This study aimed to understand the interaction between temperature and genotype in terms of the effect on early seedling development of European aspen (Populus tremula) and various F2-aspen hybrids. We evaluated the response of 16 different European aspen and F2-hybrid families on seed germination, survival rate and seedling height in one- and two-family(More)
A cost-benefit analysis of orchard seed versus seed from existing natural stands is presented for the scenario of direct sowing of Scots pine (Pinus sylvestris L.). The differential benefits of orchard seed are seed quality and improved yield due to genetic gain. These benefits are expected to further reduce the total cost of orchard seed. Seedlings from(More)
Poplars have widely been used for rhizoremediation of a broad range of organic contaminants for the past two decades. Still, there is a knowledge gap regarding the rhizosphere-associated bacterial communities of poplars and their dynamics during the remediation process. It is envisaged that a detailed understanding of rhizosphere-associated microbial(More)
pine (Pinus sylvestris L.) pollen were studied during the spring of 1993 at Turku in southern Finland (60°32′ N, 22°28′ E) and at Utsjoki in northern Finland (69°45′ N, 27°01′ E). Pollen was trapped from the beginning of May to the end of June in a high-volume air sampler. Germination tests were performed to determine the in vitro pollen viability of the(More)
In forest breeding, stem volume has typically taken as the most important selection trait, whereas less attention has been given to wood density traits. In this work, we investigated the effects of spacing and genetic entry on the growth, yield and wood density traits in 20 year old Scots pines (Pinus sylvestris L.) based on 10 genetic entries harvested(More)
The interactive effects of water and nitrogen (N) on frost hardiness are not well known in broad-leaved trees. Furthermore, new environmental conditions may favour naturally generated hybrids between native and introduced tree species over native species. A greenhouse experiment with freezing tests was carried out to study how water (low, medium, high) and(More)