The changes of colouring and content of photosynthetic pigments in unevenaged needles of Picea pungens Engelm. in conditions of urban plantings

Abstract

Objective – is to analyze the content of chlorophylls and carotenoids in the 1–4-year-old blue-coloured needles of Picea pungens Engelm. trees in street plantings of Kryvyi Rih city exposed to emissions of large metallurgical combine as well growing in non-polluted dwelling blocks of the city. Material and methods. We divided the trees into three groups at the age of less than 30 years, depending on the needle colouring: I – grey-blue, II – blue-green, III – weakly blue. The pigments of the needles were extracted by dimethyl sulfoxide, and the quantity of chlorophyll and carotenoids was defined using the spectrophotometer SF-2000. Results. In all three groups, the highest content of chlorophylls a and b as well their sum was revealed in one-yearold needles (the maximum value was in the trees of the first group), the lowest one was in four-year-old needles. Blue colouring of the needles decreases with age, especially in 3–4-year-old needles of the trees from the second and the third groups. The content of carotenoids increases with the age of the needles, the maximum is in four-year-old ones. Emissions of the metallurgical combine influence blue colouring of 2–4-year-old needles, decreasing its intensity; but this characteristics, firstly, depends on genotype peculiarities of the plants. Conclusions. P. pungens with blue-coloured needles is stable and highly decorative in conditions of a large industrial city of the steppe zone, therefore it has good perspectives to be used widely for greening of settlements in this zone.

Keywords

• Picea pungens
• needles
• blue colouring
• content of chlorophylls and carotenoids
• decorativeness
• Kryvyi Rih area