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Abstract
Introduction
Most of the data on the population variability of Scots pine refers to the features of productivity. Much less is known about Scots pine resilience. Biometric sizes of needles and theirs anatomical structure are believed to be important characteristics associated with the resistance of pine trees to adverse environmental effects.
Materials and Methods
Eight progenies of Scotch pine from clonal seed orchards from Kharkiv, Kyiv, Rivne and Volyn regions and their population controls were presented in the variety test in Gutyanske Forestry Enterprise in Kharkiv region. As a local control, the local variant Guty-control was used. The samples of needles have been selected from branches of the upper (UP) and lower (LP) part of the crown of trees in each variant and their length were measured. For the needles of the UP shoots, the parameters of the cross-section and the central cylinder were measured. The ratio between the areas of the central cylinder and the rest of the tissues on the needle cross section was calculated. The number of resin canals and their spacing on the convex and flat sides of the needles were assessed. We analyzed degrees of the variability of the investigated features. A point scale was used to compare the variants.
Results
The lengths of the needles from the shoots of upper layer were 26–120 mm and from the lower part, 21–119 mm. Differences between the average lengths of the needles of upper and lower parts were 2.3–23.2 %. The average length of the needles from both parts differed from the control within 14 %. By the length of the needles from the upper shoots, the variants originated from artificial populations had larger differences from their regional control varants than from the local control. The lengths of the needles from the lower shoots differed more significantly from the regional controls only in the next three variants: Prikhilki-1, Prikhilki-2, Lutsk-3. The differences of other variants from regional controls were smaller than from local control variant.
The numbers of resin canals in the needles of upper shoots were from 3 to 20. The average number of resin canals was 11–14 for the variants and 13 for the control. The differences between the control and variants were in the range of ±11.0 %. For the regional controls, the numbers of the resin canals were larger than those for artificial progenies from the corresponding regions, except for Kyiv-control. The largest numbers of submarginal and medial canals were found in the needles of Kharkiv-control and Volyn-control variants, and the least in the needles of representatives of Kiev and Rivne regions.
The cross-sectional area of the needles of the upper shoots was in the range from 0.61 to 2.10 mm2, and the central cylinder area was from 0.19 to 0.75 mm2. The average values of variants differed from the control within ± 25 %. The area of the central cylinder was from 21.5 to 30.4 % of the total cross-sectional area; the remaining area includes assimilation and other tissues.
An increasing variability of all characteristics was noted in the direction from the East (Cv = 11…33 %) to the West (Cv = 27…35 %), and for the linear sizes of the needles, variations were less than for the features of the anatomical structure.
The scoring based on the scale we have developed showed that two variants, local control and Lutsk-3, got the highest score (15 points). For the remaining variants, the score were below the control level and differed from it within 5 points, except for Kyiv-5, Kostopil-PLND and Lutsk-2 (less than 10 points).
Conclusions
The morphometric characteristics of the needles can be used to evaluate and compare Scots pine’s progenies from different parts of the natural range. The proposed integrated scale showed that the remoteness of the habitat of Scots pine parent plantings influences the adaptive capacity of their progenies.
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