The role of pollen in the changing environmental conditions of Scots pine
Varis S. (2010). The role of pollen in the changing environmental conditions of Scots pine. https://doi.org/10.14214/df.105
Abstract
In order to examine the long distance pollen flow in Scots pine (Pinus sylvestris L.), we measured the amount and viability of airborne pollen and flowering phenology in central, northern, and northernmost Finland during four years. Viable airborne pollen grains were detected during female flowering and before local pollen shedding in all study sites. The situation when there was nonlocal pollen in the air lasted from one to four days depending on the year and study site. The amount of nonlocal airborne pollen varied also between years and study sites, the total amount of nonlocal viable pollen in the air was 2.3% from all detected viable pollen grains. The effect of pollen origin on seeds siring ability was studied with artificial pollination experiments. Pollen genotypes originating from southern Finland sired 76% and 48 % of the analysed seeds in competition studies where both pollen origin were introduced simultaneously into the female strobili. We examined the importance of arrival order of pollen grains in to the strobili in a study where pollen genotypes of different origin were introduced in two hours interval. Northern genotypes sired 76% of the analysed seeds when it was injected first, but in the "southern first" experiment both pollen types sired equal amount of seeds. The first pollen grain in the pollen chamber do not always fertilizes the ovum, instead there likely is more complex way of competition between pollen grains. To examine chemically mediated pollen-pollen interactions we conducted in vitro germination experiment where different pollen genotypes had chemical but not physical contact. Both positive and negative effects of interactions were found. We found highly negative effects in germinability of northern pollen grains when they were germinating with southern pollen, and increase in the germinability of southern pollen. There were no variation in the size of the dry pollen grains between pollen origins, and minor variation between different genotypes. After hydration and germination northern pollen grains were larger than southern pollen. Long distance pollen movements and good competition ability of southern pollen makes gene flow possible, although rising temperature and timing of pollen movements may affect pollen competition and the amount of gene flow.
Keywords
long distance pollen movements;
gene flow;
pollen competition
Published 14 May 2010
Views 3360
Available at https://doi.org/10.14214/df.105 | Download PDF
Original articles
Varis, S., Pakkanen, A., Galofre, A. & Pulkkinen, P. 2009. The extent of south-north pollen transfer in Finnish Scots pine. Silva Fennica 43: 717-726.
https://doi.org/10.14214/sf.168
Pulkkinen, P., Varis, S., Pakkanen, A., Koivuranta, L., Vakkari, P. and Parantainen, A. 2009 Southern pollen sires more seeds than northern pollen in southern seed orchards established with northern clones of Pinus sylvestris. Scandinavian Journal of Forest Research 24: 8-14.
https://doi.org/10.1080/02827580802592467
Varis, S., Santanen, A., Pakkanen, A. and Pulkkinen, P. 2008. The importance of being the first pollen in the strobili of Scots pine. Canadian Journal of Forest Research 38: 2976 - 2980. https://doi.org/10.1139/X08-13
Varis, S., Reininharju, J., Santanen, A., Ranta, H. and Pulkkinen, P. 2010. Interactions during in vitro germination of Scots pine pollen. Trees - Structure and Function 24: 99-104.
https://doi.org/10.1007/s00468-009-0382-4
Varis, S., Reininharju, J., Santanen, A., Ranta, H. and Pulkkinen, P. The size and pollen germinability in different temperatures. Manuscript.