@misc{Robakowski_Piotr_Acclimation_2003,
 author={Robakowski, Piotr and Wyka, Tomasz},
 editor={Polish Academy of Sciences. Institute of Ecology},
 copyright={Licencja Creative Commons Uznanie autorstwa 3.0 Polska},
 address={Dziekanów Leśny},
 howpublished={online},
 year={2003},
 language={eng},
 abstract={To determine the influence of tree canopy composition on growth and physiological performance of silver fir (Abies alba Mill.) in Karkonoski National Park (Sudety Mountains, Southern Poland), three-year-old fir seedlings were planted in five forest stands dominated by Betula pendula, Fagus sylvatica, Larix decidua, Picea abies or Pinus sylvestris. The stands differed in canopy openness such that young fir plants experienced drastically different light environments. After three years of acclimation to site conditions, length of shoots, seasonal changes in chlorophyll a fluorescence parameters, and the contents of chlorophyll, carotenoids and nutrients in the needles were studied to evaluate the seedling performance. Growth and photosynthetic characteristics of the young seedlings responded strongly to local light conditions. The lengths of leader shoot and twigs of the upper whorl reflected variation in canopy openness during the growing season and were highest under Larix. The potential quantum yield of photosystem II (Fv/Fm) showed a strong depression in the spring, especially under the leafless canopies of Betula and Fagus, probably because of the occurrence of low air temperatures. Later in the season Fv/Fm showed substantial recovery in all stands. Effective quantum yield ΦPSII measured under actinic light also showed a growing trend throughout the season with the lowest levels noted in the spring, particularly under Fagus and Betula. Fluorescence quenching revealed complex seasonal behaviour with little obvious relationship with stand illumination, except for consistently low value of photochemical quenching, and immediate or high nonphotochemical quenching under the dark Picea canopy, probably reflecting photoprotective acclimation to sunflecks. Although needle chlorophyll content showed no relationship to ambient light, the ratio of carotenoids to chlorophyll was positively linked to canopy openness suggesting the existence of leaf photoprotection that evaded detection by quenching analysis. Nutrient contents in needles depended on site conditions. In the light-transparent Larix stand, the fir needles were strongly depleted in Mg and Ca. Overall, however, all fir plants from experimental plots had much lower needle nutrient content than nursery-raised plants. Needle chlorosis found in Betula and Pinus stands was, however, not caused by macronutrient deficiencies. Considering all variables, conditions most conducive for fir growth and good vigor were found under larch and pine canopies where light penetration was intermediate to high. In contrast, the poorest conditions were found in the Betula stand, where high light penetration in the spring was followed by shading of firs during the growing season.},
 title={Acclimation of silver fir (Abies alba Mill.) seedlings to irradiance conditions under canopies of different tree species in Sudety Mts. (Southern Poland)},
 type={Tekst},
 URL={http://rcin.org.pl/Content/117557/PDF/WA058_91637_P2840-T51_Eko-Pol-A-Nr-3.pdf},
 volume={51},
 number={3},
 journal={Polish Journal of Ecology},
 publisher={Polish Academy of Sciences. Institute of Ecology. Publishing Office},
 keywords={Abies alba, acclimation to light, reintroduction, canopy density, pigment content, chlorophyll fluorescence, nutrient content},
}