© 2000 Heron Publishing—Victoria, Canada
Genetic and environmental control of seasonal carbohydrate dynamics in trees of diverse Pinus sylvestris populations
J. Oleksyn (1, 2), R. Zytkowiak (1), P. Karolewski (1), P. B. Reich (2) and M. G. Tjoelker (2)
1. Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62-035 Kórnik, Poland / 2. University of Minnesota, Department of Forest Resources, 115 Green Hall, 1530 Cleveland Avenue N., St. Paul, MN 55108-6112,
USA / Received September 28, 1999
Summary
We explored environmental and genetic factors affecting seasonal dynamics of starch and soluble nonstructural carbohydrates
in needle and twig cohorts and roots of Scots pine (Pinus sylvestris L.) trees of six populations originating between 49° and 60° N, and grown under common garden conditions in western Poland.
Trees of each population were sampled once or twice per month over a 3-year period from age 15 to 17 years. Based on similarity
in starch concentration patterns in needles, two distinct groups of populations were identified; one comprised northern populations
from Sweden and Russia (59–60° N), and another comprised central European populations from Latvia, Poland, Germany and France
(49–56° N). Needle starch concentrations of northern populations started to decline in late spring and reached minimum values
earlier than those of central populations. For all populations, starch accumulation in spring started when minimum air temperature
permanently exceeded 0 °C. Starch accumulation peaked before bud break and was highest in 1-year-old needles, averaging 9–13%
of dry mass. Soluble carbohydrate concentrations were lowest in spring and summer and highest in autumn and winter. There
were no differences among populations in seasonal pattern of soluble carbohydrate concentrations. Averaged across all populations,
needle soluble carbohydrate concentrations increased from about 4% of needle dry mass in developing current-year needles,
to about 9% in 1- and 2-year-old needles. Root carbohydrate concentration exhibited a bimodal pattern with peaks in spring
and autumn. Northern populations had higher concentrations of fine-root starch in spring and autumn than central populations.
Late-summer carbohydrate accumulation in roots started only after depletion of starch in needles and woody shoots. We conclude
that Scots pine carbohydrate dynamics depend partially on inherited properties that are probably related to phenology of root
and shoot growth.
Keywords:
defoliation, needle, phenology, provenance, root, soluble carbohydrates, starch, shoot.
