CENTRE ON THE PROBLEMS OF ECOLOGY AND PRODUCTIVITY OF FORESTS

RUSSIAN ACADEMY OF SCIENCES

Vasfilov S.P. Age variability of needles in Scots pine crown // Forest Science (Lesovedenie). 2014. No 6. С.41-48.

Variability of morpho-physiological traits in needles of all ages in the pine crown is studied. On the tip (full natural light exposure) the larger needles with smaller longevity is produced compared to a bottom part of the crown. Water content, dry weight, organic acid and sugar contents per unit length of a needle are controlled by the size and position in the crown. However these factors do not affect water content per unit dry weight, which decreases with age in all of a crown. pH is not affected by size of aged needles. pH is controlled by age of a needle and a season, varying during vegetation and staying rather constant during winter dormancy. The less the organic acid contents the more the рН of needles during vegetation, with more pronounced difference in the upper crown. Water and organic acid contents decrease, while tissue pH and sugar contents increase during vegetation with ageing of needles. pH increase correlates with sugar content and reduction in organic acid content. Sugars are accumulated in needles of all ages during winter dormancy, with the least capacity in aged needles. High luminance speeds up the aging decreasing longevity of needles. Based on the data we suggest that environmental factors favorable to photosynthesis speed up the aging, decreasing the longevity of needles.

Pine, variability, needle longevity, aging, length, dry weight, water, pH, organic acid, sugar..

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