Thu, Aug 18, 2022: 2:15 PM-2:30 PM
513A
Background/Question/Methods
The majority of terrestrial primary production is performed by plants, the ontogenetic growthtrends of which greatly influence biomass and carbon dynamics. We study ontogenetictrends of primary (apical) and secondary (stem thickening) growth in the Arctic (Svalbard,Norway) and alpine (Krkonoše, Czechia) populations of black crowberry (Empetrum nigrum),the dominant plant species of certain tundra communities. The environmental conditions inalpine areas are more favourable for plant growth than those in the High Arctic, wheretemperatures are lower, there is less precipitation and soils are shallower, among otherdifferences. Using dendrochronological methods we sampled two populations from the distinct regions in order to understand the growth ecology (i.e. ontogeny) of this species under diverse environmental conditions.
Results/Conclusions
The differences in the environmental conditions were clearly reflected in significant differences in absolutegrowth rates and shrub age between the populations under study. However, we found almostno differences in ontogenetic growth trends between the populations. In both populations,primary growth and secondary (stem base) growth decrease over the course of ontogenywhereas secondary (stem top) growth and basal area increment increase. No significantdifferences in the slope of the trends were found in either primary or secondary (stem base)growth. Trends of the ratio between basal area increment and primary growth revealed neitherabsolute nor relative differences between the populations. Ontogenetic trends in the shrubsanalysed were surprisingly stable despite the prominently different environmental conditions.Empetrum plants have adapted to the different environments by altering their absolute growthrate only. This adaptation has probably also resulted in the different longevity of plantsconstituting the study populations, confirming the theory that slower-growing plants livelonger. Primary growth and secondary (diameter) growth at the stem base seems to be morebasic characteristics of plant growth compared to basal area increment and secondary(diameter) growth at the apex because the latter two seem to be dependent on the absolutegrowth rate.
The majority of terrestrial primary production is performed by plants, the ontogenetic growthtrends of which greatly influence biomass and carbon dynamics. We study ontogenetictrends of primary (apical) and secondary (stem thickening) growth in the Arctic (Svalbard,Norway) and alpine (Krkonoše, Czechia) populations of black crowberry (Empetrum nigrum),the dominant plant species of certain tundra communities. The environmental conditions inalpine areas are more favourable for plant growth than those in the High Arctic, wheretemperatures are lower, there is less precipitation and soils are shallower, among otherdifferences. Using dendrochronological methods we sampled two populations from the distinct regions in order to understand the growth ecology (i.e. ontogeny) of this species under diverse environmental conditions.
Results/Conclusions
The differences in the environmental conditions were clearly reflected in significant differences in absolutegrowth rates and shrub age between the populations under study. However, we found almostno differences in ontogenetic growth trends between the populations. In both populations,primary growth and secondary (stem base) growth decrease over the course of ontogenywhereas secondary (stem top) growth and basal area increment increase. No significantdifferences in the slope of the trends were found in either primary or secondary (stem base)growth. Trends of the ratio between basal area increment and primary growth revealed neitherabsolute nor relative differences between the populations. Ontogenetic trends in the shrubsanalysed were surprisingly stable despite the prominently different environmental conditions.Empetrum plants have adapted to the different environments by altering their absolute growthrate only. This adaptation has probably also resulted in the different longevity of plantsconstituting the study populations, confirming the theory that slower-growing plants livelonger. Primary growth and secondary (diameter) growth at the stem base seems to be morebasic characteristics of plant growth compared to basal area increment and secondary(diameter) growth at the apex because the latter two seem to be dependent on the absolutegrowth rate.