Variability of photosynthetic parameters of Pinus sibirica Du Tour needles under changing climatic factors

• Main Authors: A.P. Zotikova, T.I. Rudnik
• Format: Article
• Language: English
• Published: ‘Marin Drăcea’ National Research-Development Institute in Forestry 2013-12-01
• Series: Annals of Forest Research
• Subjects: pinus sibirica, ecotype, photosynthetic parameters, chlorophyll, carotinoids, uv radiation, photo-system ii
• Online Access: https://www.afrjournal.org/index.php/afr/article/view/165

<p>The air temperature and relative humidity and the intensity of photosynthetically active radiation are the basic ecological factors determining geographical distribution of a species. Wood plant adaptation depends on the intensity of physiological and biochemical<br />processes of plants as a response to changing environmental factors. Investigations to reveal (detect) the variability of modification and<br />genetic components of the photosynthetic parameters in needles of the Siberian cedar (Pinus sibirica Du Tour) mountain ecotypes, distributed in central part of the Altai Mountains, were carried out. Also, the survey was extended to some experiments with these ecotypes introduced to mild climate and flat regions from south-western of Siberia. The length and thickness of needles, the size of chloroplasts, content of the photosynthetic pigments, and the functional activity of chloroplasts<br />at the level of photo system II were the evaluated traits. Growing under mountainous conditions (at about 2000m elevation), the two-year-old needles were shorter and thicker and contained very large in size chloroplasts while the content of chlorophylls and carotinoids was twice lower than that in the local ecotype growing in the lowlands. On the other hand, more green and yellow pigments were found in needles of mountain ecotypes planted in the lowlands compared to the local lowland ectype trees. A decrease in pool of the photosynthetic pigments in the highlands ecotypes is probably due to decreased biosynthesis and<br />increased photo-destruction caused by severe light and temperature conditions. These parameters are likely to be associated with<br />modifications due to intense insolation, low temperature, ozone concentration, UV radiation, and other negative factors that are more<br />pronounced at high elevation. Despite the large pool of accumulated photosynthetic pigments, the functional activity of chloroplasts in the<br />mountain ecotype at the level of photosystem II was lower than that in the local ecotype. Thus, the increased photosynthetic intensity under favorable conditions follows the path of formation of both a larger number of reaction centers and light-harvesting pigments.</p>